Solar Investigation : How many solar panels do you need?
- Filed under: Solar Power and Off-Grid Living
- Date: Apr 11,2008
I’ve already written a few articles about solar power, this one is going to be ONLY about figuring out how many solar panels you need to buy to meet your electrical needs.
If you’re currently living with “regular” power, and are wanting to switch it all over to solar, you’re in for a pretty large investment. (Well over $10000) However, if you just need some power for a weekend cottage, an RV, a garage, etc ; solar power may be a great option !
The first step is figuring out how many WATTS of power you use every day. Basically, Watts = Volts * Amps. I do all my calculations in WATTS. If you don’t know what a WATT is, just think of it as a unit of power. That’s all you REALLY need to know to understand this article.
Most household appliances run on either 120 volts AC (The Americas), or 220 VOLTS. (Most other places) You should atleast know what you’re running before going any further. If you don’t, i’m sorry, I can’t help you. Maybe you can send me an email telling me where you live … 
Make yourself a chart listing everything you NEED to run on solar electricity, how many hours per day you want to run it, and how many AMPS it takes. (Look on the unit, under it or behind it, there should be a sticker that says INPUT 120 volts XXXX amps or something along those lines) Multiply the volts by the amps and you will get how many WATTS that thing takes per hour of run time. Add that to your chart for each item.
Here is a small chart of the approx. watts per hour certain things take (List from EVSOLAR) :
| Appliances | Watts | Appliances | Watts |
| Blender | 300 | Refrigerator (20 cf.) | 150 |
| CB radio | 5 | Satellite dish | 30 |
| CD player | 35 | Sewing machine | 100-500 |
| Ceiling fan | 10-75 | Table fan | 1-25 |
| Clock radio | 1 | Toaster | 800-1500 |
| Coffee maker | 800-1200 | TV: 25″ color | 150 |
| Computer | 80-150 | TV: 19″ color | 70 |
| Dishwasher | 1200-1500 | TV: 12″ B&W | 20 |
| Dryer (elec.) | 4000 | Vacuum cleaner | 200-1200 |
| Dryer (gas) | 300-400 | VCR | 40 |
| Elec. blanket | 200 | Waffle iron | 1200 |
| Elec. clock | 3 | Washing machine | 500 |
| Evap. cooler | 300-1000 | ½” Drill | 900 |
| Frying pan | 1200 | 71/4″ Circ. saw | 750 |
| Furnace blower | 300-1000 | ||
| Garage door opener | 350 | Lights: | |
| Garbage disposal | 450 | 100W Incandescent | 100 |
| Hair dryer | 900-1500 | 60W Incandescent | 60 |
| Iron | 900-1200 | 25W Incandescent | 25 |
| Laptop | 20-50 | 25W Comp. flourescent | 28 |
| Microwave | 600-1500 | 15W Comp. flourescent | 18 |
| Printer: laser | 300-475 | 42W Halogen | 42 |
| Printer: ink jet | 60-75 |
Running a standard fridge on solar power is tricky. I wouldn’t recommend it. You have to get a fancy 12 volt fridge, or a propane fridge. Otherwise you’re looking into a LARGE investment to get the proper inverters to support the start up load and enough solar panels to keep up. That’s not what this article is about though.
So now you should have a chart with all the electrical things you want to run, how many hours per day you will run it, and how many watts per hour it takes while running. Multiply the WATTS by the HOURS for each item, and then add up all your readings. This will tell you how many watts per day you will be using.
At this point in time, you need to decide how often you will be using this amount of power. If it’s for a weekend cottage, you don’t need to recharge the batteries in one day, you have all week to charge the batteries to last a weekend. If you’re using it for an off-grid house however, you need to replenish your battery bank on a daily basis. For this article, we will pretend you need to replenish the battery bank every day.
Lets say you NEED 1500 watts of power per day to run all of your electrical needs, EVERY DAY. This means 
you need your solar panels to add atleast 1500 watts of power into your batteries. (off grid solar systems ALWAYS runs on batteries. Panels charge a bank of batteries, batteries powers inverter, and inverter supplies regular 120 volt electricity) I like to not be too optimistic when sizing systems, so I pretend there’s only 4 hours of useable sun per day. So we need to create 1500 watts total in a day, and we have 4 hours to get it in. 1500 watts divided by 4 hours means we need to make 375 WATTS of power per hour.
Solar Panels are rated in this format as well. (Watts per HOUR). If you research solar panels, and one is advertised as being 100 Watts, it means it creates 100 watts of power per hour of sunlight. We’ve decided above that we need 375 Watts of panels in order to meet our minimum power requirements. In this case, I would buy 4 100 WATT panels to make 400watts per hour of sunlight. (Times 4 hours means 1600 Watts into the batteries every day, enough for all your power needs and to make up for Inverter losses)
THAT’S how I calculate how many solar panels are needed for your solar array.
If you’re looking for LOTS of information on solar power and wind power systems, you might consider buying these sets of e-books that are filled with tips and tricks for solar power.
Stay tuned at TechieNATION.com for my future article about figuring out how many batteries you need for your solar installation!
168 Responses for "Solar Investigation : How many solar panels do you need?"
i am in the process of setting up a solar system and i have the article very informative
i live in jamaica and we have sunlight 12 to 14 hrs all year round yet i find the vast majority of the inhabitants are still pay the utility company
thousands monthly and we have free energy we can tap into
ignore the typographical errors i did not proof read
I would kill to be in a place that got so much sunlight. It will really maximize the power you get from your solar panels !
Good luck with your project, feel free to contact me at digitalmind (AT) techienation (DOT) com if you have any questions or need some help.
(You can also chat with me when i’m online, near the top left sidebar on this site it says LIVE SUPPORT ONLINE or OFFLINE, just click on it to chat when i’m online)
Let us know how your solar install goes, and take pictures if you can !
i plan on using a 2500w inverter , (2) 110w panels (initially ) along with (2) deep cycle batteries rated at 12v and 115amps
the inverter and charge controller would be mounted on a piece of 5/8
ply backboard and the batteries on a stand I think that is a better option than in the pan)
i however am very keen on running everthing in the house ultimately on solar power but i was a bit put off to read that to run a fridge requires a significant outlay
what are your thoughts
i plan on getting some of the items in the coming week
Will you be hooking up the batteries in series to have a 24 volt 115 amp hour system or in parallel to be a 12 volts 230 amp hour system ?
Have you calculated how many watts per day you will be using ?
You seem to have more panels than you do batteries. 220 watts of panels, * 10 hours per day of sun = 2200 Watts Generated per day.
Your battery bank (lets say you hook it up as 12 volts 230 amp hours) can only hold 12 * 230 amps which is 2760 Watts, but you should never use more than half your battery bank so you only have 1380 watts in your batteries to play with. You will be generating more power with your panels in a day than what your batteries can take in. (Which is ok if there’s stuff taking a good chunk of power DURING the day) If you do this, DON’T FORGET TO GET A GOOD CHARGE CONTROLLER ! The charge controller is what will stop your panels from overcharging your batteries.
Since you’re lucky to get so much sun, I wouldn’t be surprised if you can pull of running a fridge on solar power. It will have to be a very energy efficient fridge, and that still depends on what other things you will want to be running on solar. ALSO, (and this is the hardest part) you need a really good inverter that will support the startup of the compressor for your fridge. What brand is your 2500 Watt inverter?
Thanks for the comments, and good luck !
i am getting a little confused .you said in your article that the wattage on an appliance is per hour of run time right?
now my fridge (a 20cf) uses 445w plus maybe a tv and a fan during the day and oh yes the computer making an approximate total of
700w/hr.follow me now if i place that load on the system
the batteries (connected in parallel) should be able to run for awhile until the batteries run low as the panels would only be generating 220w of power per hour so for the 10 hr period i would require 7000 watts am i right or am i totally confused and in the night it gets worse as there would now be maybe two bulbs and two tvs on
so in my mind i need more panels
to answer the other questions i dont know what brand inverter as i plan to do the purchases weekend
by the way what kind of 20cf fridge uses 150watt ( looK at your list)
Yes you are right you would require 7000 Watts for that 10 hour period.
During that 10 hour period if the sun is shining you’ll have added 2300 Watts into the batteries via the solar panels, so technically in that 10 hour period you’re using almost 5000 Watts more than you’re generating. (So you’re taking that power from the batteries)
The way to figure out exactly how many panels and batteries you need is to calculate your daily totals in power consumption. If this place is being used every day, you need enough panels to generate the same amount of power you use in one day. You should have enough batteries to sustain yourself for ATLEAST 24 hours without sun in case of emergency.
So far you’ve told me that you will be USING 7000 WATTS of power in 10 hours time, yet you’re only generating 2300 Watts of power so your power level is ALWAYS going down. Technically in a couple of days you will have NO batteries left and you will only have power WHILE the sun is shining. (And only 230 Watts MAX per hour to use)
Can you give me the TOTAL WATTS you will be using in a day ??
I really, REALLY recommend getting a propane fridge unless you have a big budget for your solar setup.
Here is the chart I made a while back while sizing a “small” solar system for someone :
Item Hours per Day Watts / HR Watts / Day
Small cooler fridge 24 36 864
Ceiling lights (x5) 5 55 275
Lamp 10 11 110
Laptop 10 180 1800
Cell phone charger 1 20 20
Total 3069 Watts
Total Usable Watts with 6 batteries : 3960 Watts
Solar Panels Required to recharge every day : 4 (About 175 Watts Per Panel Per hours of sunlight – 5 hrs calculated per day)
Where did you get the number for the power your fridge takes? (The 445 Watts??) The thing with fridges is that they take LOTS of power to turn on, and then little power to keep going. You should call your fridge manufacturer, and they could probably tell you the average power consumption of your model fridge in a year. Then divide by 365. But again, you need an inverter that will handle that high startup power from the fridge.
I know this is lots of information, hope you’re not going to give up !!! My head was spinning for months while learning this. I met with electricians and a solar specialist so that I can understand it all ..
Good luck, keep me updated !
i think i will keep i simple initially by finding a way to run the other appliances with the solar system because the power generated should be more than sufficient
later i will endeavour to up grade to accommodate the fridge
by the way the label on the fridge is in spanish it reads
limite de consumo de energia(kwh/ano) 484
consumo de energia(kwh/ano) 450
my limited spanish give me the impression that it says that the consumption is 484 or 450 kwh per year
how is your spanish?
i wish as one global nation we would all be more concerned about alternative forms of energy as the price of oil is ridiculous ( and it is being artificially manipulated) maybe you can use your site to start spreading the word that we need to take a more proactive approach to limiting our use of fossil fuel
as we say in jamaica :”we need to do something before something do us” if you understand
2 things :
1 – Great idea to start slowly and migrate your things over to solar power to see how far you can go with what. You can do a lot with 230 Watts of Solar Panels and 10 hours of sun per day !!! (Seriously, i’m so jealous of you right now!)
2 – My spanish is horrible, but it’s obviously saying it takes an average of 450 KiloWattHours per YEAR. That is NOT the same as 450 Watts per hour. Not at all.
That fridge will eat up 450000 Watts in a year. Divided by 365 days = 1232 Watts per day (Average), divided by 24 hours a day means that fridge is using roughly 52 Watts per hour. If you had nothing else running on Solar, you could run this with your 2 panels and 2 batteries assuming your inverter can handle the Start up Current (which is MUCH higher than the average current it’s pulling).
great !!
by next week i will be able to tell you on my progress i will even upload some pictures if possible
That’s great Oral, I look forward to hearing about how it goes !! DON’T FORGET TO INSTALL A CHARGE CONTROLLER !!!!! (It won’t take long for your panels to completely recharge your batteries)
I will send you an email soon so that you can know where to email the pictures too. I’ll write an article about your installation once done !
DigitalMind
Dear(!) DigitalMind,
I buyed a house with NO electricity (grid), there is just a small solar installation with 4 panels 85 w and 2 car batteries of 180 Amph eatch.
The house in the nord of Spain so we have there 8 hours piek sun / day.
Where i live now i consume 6500 Kw/year.
I want make a installation or this amount of electricity over there.
The solarpanels i can buy are 230 wp.
How much panels and houw much deepload betteries and type, and wich converter(s) i need for this installation, let say with a reserve of 500 kw/year what ives us 7000kw/year.
Can you calculated this for me ?
Sorry for the grammatical foalts, because englisch is not my moher language.
how many volts are your 2 X 180amp/hour batteries ? (I’m wondering if you have a 12 volt 180 amp/hour system, or a 12 volt 360 amp/hour system, or a 24 volt 180 amp/hour system)
I am going camping for the weekend, and will give you my estimates as to how many panels and batteries you need to get your 7000kw per year when I return on Monday.
Speak to you soon !
Hello Digimind,
Good article! I have a few questions concerning a solar project I am doing for my school work. Would you know how many volts or watts a small refrigerator of about 1.7 cf carries, and how much solar panels I would need to power it? How much should I estimate for this project? Kindly give advice on anything else I may need to know concerning this project.
Thanks.
Hi Chike,
fridges are kind of complicated. First of all, look at the back of the fridge and look at how many amps it pulls at what voltage. Volts * Amps = Watts used per hour. For a fridge it’s not so accurate. Fridges use a LOT of power for a short period of time, and then uses very little power for a long time. The very BEST way to get the power consumption of your fridge is to call the customer service people of the manufacturers. They will tell you the total Kilowatt hours per year that your model uses, and will probably be also able to give you the startup current.
Sorry this was probably not the simple answer you were looking for.
I tell people to invest in a 12 volt fridge if they plan to run it on solar. Much more efficient and you don’t have to spend a fortune on an inverter to power the fridge. (And inverter’s have power losses too even when nothing is turned on)
hi digitalmind
i have been quiet for a while becuse in addition to other things i have been doing a whole ton of research on alternative energy and what i have come across is the wind alternative
even though i have in hand a 2.5kwatt inverter and charge controller i have not proceeded further as i am really trying to weigh both alternatives when you bear in mind that where i live in jamaica is not only sunny but also windy
what are your thoughts on both as energy sources
Hi Oral ,
It’s nice to hear from you again ! It’s funny that you mention this now since I just finished writing my first blog post about wind power
. ( http://www.techienation.com/understanding-wind-power-wind-generators-turbines/ )
From what I gather, wind power is cheaper as long as you have the wind and the ability to put it all together. The price per Watt generated by wind turbines is always much lower than the cost of solar panels ESPECIALLY, if you learn how to build you own wind turbine, which is what i’m working on now.
Solar is a lot easier though. (unless you’re buying a pre-made wind turbine, and in that case the only “hard part” is putting up a pole or tower to hold up the turbine in less turbulent winds)
I was intimidated with building my own turbine for a long time, but now I feel confident I can do it.
Keep me updated ! Can’t wait to see what your installation will look like !
i am still in the initial stages of indecision as to the best motor to use i am partial to an alternator or if i can find a suitable permanent magnet motor . i guess that the motor would be best as i think an alternator requires a current to run the field coil
the rest is fairly easy .
the proper motor is my problem right now
From what I understand an alternator is not the best solution because it requires a high RPM. You would need to gear it up in a certain way to make it close to efficient.
I would suggest getting a good AMETEK PM motor (Use Ebay), or if you’re able too, make your own and that will really give you the best bang for your buck.
i am checking ebay
Thank you for your information .
Jimmy
Your welcome Jimmy Alan,
If you have any questions, feel free to post them. I’ll answer and maybe it’ll inspire me to write an article about it.
i have a swimming pool that needs the filters to be ran for 8 hours it really hurts my wallet. so i wanted to make it a solor powered pool. i see that its powered between 120/220 volts. i want to know what size solor panel would be good enough for me to run the filters for 8 hours. whats better solor or turbine power.
@Charles : Solar power is easier to setup. you get more bang for your buck with wind. Look at the pump and find out how many AMPS it uses at 110 volts. Let me know, and then i’ll be able to give you some options.
Welcome to techieNATION !
well i looked on the motor and i think its 125 amps. i found a place that sells a 45 watt solor panel kits for $219 do you think that will be enough. or do i need a power inverter 2. thanks
Charles, I’m SURE it doesn’t take 125 Amps. Maybe 125 volts, or 125 Watts, but not Amps. Could you clarify for me please ? A 45 Watt panel won’t do much. You will definitely need an inverter though because your filter doesn’t run on 12 or 24 volts i’m pretty confident.
If you can get a picture of the label with the power specs, you can send it to me at digitalmind (AT) techienation (DOT) com and that’ll help me help you figure out exactly how many panels you would need.
Pls Sir,
How can i calculate the inverter/battery requirment for a load of 200W to take me the whole day?
I live in Nigeria and have bought an inverter of 1000W/600VA made in China with battery bank of 200W which i have not started using.
Thanx
Helen
Hi Helen,
I’ll need a few more details. Are you saying you’ll have a 200 Watt load that will be on all day ? (24 hours per day) Or you need to power something that takes 200 watts in TOTAL in a day ?
Also, please give details on the batteries. Because a 200 Watt Battery bank basically means you’ll only be able to run your 200 watt load for 1 hour and then the battery will be completely dead. Maybe you have a 200 AMP battery bank ?
Lastly, how are you planning on recharging these batteries ? Solar Power ? Generator ? Wind Turbine ?
Take care, I look forward to getting more details …
Dear Sir,
Very happy to have your reply almost immediately.
Actually, i need to power load of 200W in a day. And my battery capacity is 200Amp.
Finally, i am planning to have a 12V battery charger separate because i dont think the inverter has the capacity to charge heavy duty battery of that magnitude.
Also, pls advice me on the charger type and capacity that will charge a 200Amp or more effectively.
What do you think will be the charging time to have a 200Amp battery or more effectievly charged?
All the best!
Helen
Dear Sir,
Very happy to have your reply almost immediately.
Actually, i need to power a load of 200W in a day. And my battery capacity is 200Amp.
Finally, i am planning to have a 12V battery charger separate because i dont think the inverter has the capacity to charge heavy duty battery of that magnitude.
Also, pls advice me on the charger type and capacity that will charge a 200Amp or more effectively.
What do you think will be the charging time to have a 200Amp battery or more effectievly charged?
All the best!
Helen
We are downsizing into a mobile home and hoping to at least have some of our power such as lights, washer,TV’s to be powered by a solar installation and the 220 appliances by the utility company. Can this be done? Kim Long in Texas
Hey just got washed out by hurricane IKE and would like to know if I would need a battery bank if I’m only looking to help reduse the amount of power off the grid I’m going to use. Will the inverter tie into the grid or a’m I just lost? I do plan on rebuilding on the beach.
Kevin
Sorry I’ve neglected to answer a few people, here it goes.
@Helen : I can’t imagine what would take 200 watts per day. That’s really not a lot. Are you sure it’s not 200 watts per hour ? Either way, here are some things to think about :
Your 12 volt 200 amp battery holds 2400 watts of power. (volts x amps = watts)
You shouldn’t discharge your battery more than 50%, so you have 1200 watts of power to use in that (or those) batterie(s). If whatever you’re trying to power really only uses 200 watts TOTAL per day, you can run it for 6 days before needing to recharge your batteries.
An Inverter is not used to charge the batteries. The inverter converts the 12 volt power from the batteries into regular power like you have in your home.
To charge the batteries there are a few options.
Obviously this entire post is about solar power, so solar panels could be used to recharge the batteries. If you really only need 200 watts per day, and I guess that you get 5 hours of sun per day, then you only need 40 watts worth of panels. That would cost around 300$. This would be green renewable energy that has no costs after. (You would need to buy a charge controller, about $50)
You can get a gas powered Generator that would be used every 6 days.
You can hook up jumper cables between your car and the batteries every 6 days and leave the car running. (Although this should not be a permanent solution)
The charging time depends on the power of the generator. I’d go with solar if it’s possible since you need so little. I take it there’s no regular power you can use anywhere ?
Hey Kevin
You dont need a battery bank if you are just wanting to reduce your electric bill. Yes the inverter will tie into the grid. You should have your solar pannels going to a dc shutoff, then going to the inverter, then going to an ac shutoff, then tie into the box on your house that is coming from the grid. I would suggest that you get an electrician to hook up the ac shut off to the grid. The DC shutoff and AC shutoff will allow you to easially shut of power to your pannels to service them or to add new ones. You will also need to be able to shut off your power to the grid if the grid goes out so you dont injure anyone working on the lines.
Doing it this way is probably the best way to start. This way you can use the grid as your battery bank. Just keep adding pannels until you get your meter spinning backwards then start buying batteries.
Digitalmind..
Did you get to work on your wind turbine yet? If you need any help with that I have been working on it myself for a few weeks now. I have some equipment being delivered this week to get it all hooked up. I have some videos on youtube on some vertical axis wind turbines that I have been working on. I am new to this but I have been doing alot of research. Thanks for all your info on this page. It has helped me a great deal on figuring out how much power I will need.
Alan
Alan, you say that you tie the inverter into the grid. I have been looking for a converter to be able to use 220 volts on my house. You have to have 220volts for a stove, dryer and other appliances. I am trying to use both solar and wind for my power and i have been looking for an inverter to be able to do this without any luck. I just do not see how you can tie it into the grid. Do you have any pics depicting this dc shutoff and the ac shutoff in use. I would appreciate your help. I am new to this and i am trying to learn as i go. I am dead set on getting independent from the power company. I live in Kentucky and i just hope that i can get enough power from the wind.
Jody
Hi Jody,
Sorry I never had the time to answer your original question, but Alan pretty much has it on the nose. The simple way of saying what he said : Get a Grid-Tie inverter and get a qualified electrician to install that part. (Just google grid-tie inverter)
DigitalMind
We have a sailboat that will be completely off the grid…need to get solar panels….electricity needs calculated at 1050watts for 10 hours of usage for laptop/lights/cbradio/fan/cell charger all going at the same time. . Does the solar panel generate watts/hr directly into the battery and the battery hooks into the boat’s inverter so I can plug into the outlet?
What is a charge controller? I think that I have it figured that I only need a 12v 200amp battery. I am cruising in florida so plenty of sunny hours to charge in a day.
Any other advice?
thanks
Hallo iam writing from kenya. My question is i have 2 solar panels of 50w and 25w, 600w invertor and 2 12 volt car battery,and plenty of sun 10hrs. I want to run 1000w load for like 6hrs during the night. Is it possible and pliz advice me on the connections.
sir, i want to know is it cheaper for me to get current out of a generator or dc inverters hooked up to a car. lets say i need 3500watts for 8 hours, which will be cheaper for me to start, a generator or a small car? neil
Hello I;m looking at buying 2 Solar panels 210watts so total of 420watts this Monday and was wondering what items I can purchase to go along with it.
This is a link to the two panels I’m getting so you know which ones I”m talking about.
SUN-A-210
http://sunelec.com/index.php?main_page=index&cPath=5&sort=20a&page=3
. I don’t want an off the grid hookup. I want to be able to move this thing with me wherever I go including batteries etc.
Can you tell me what charge controller is best since I have two panels?what batteries deep cycle 12v for more power I believe?. What wires cables..inverters..?Every thing I would need. I would like to get at lease 1500 watts of power per day to run all of my electrical needs if possible I am new to this if I can can get more some other way let me know.
Also I live in Maine where its cloudy 1 min sunny the next then cloudy for hours.
Thanks for your time
Greg
Can someone help me? I need to cover a space of 1 to 2 acres with solar panel, but I don’t know what parts I need, how many, or much this thing would cost. I appreciate any feedback.
Michell
March 9th, 2009 at 4:42 pm
i can be contacted at multiSync25635@gmail.com
Michell,
This question doesn’t really make sense. Unless you’re planning on building your own solar farm, it’s not about how much space you have but how much power you need to generate. You can fill an acre with 10 watt panels, or you can fill it with 200 watt panels…. What is it you’re trying to do ?!?!?! If you are planning on building your own solar farm, I would hope that at this point you would already know what parts you need, otherwise you’re just getting WAY ahead of yourself. Read the pages here on solar power first.
Let me know !
“UPDATE CORRECTION ABOVE ON MY LAST POST, I WANT AN OFF THE GRID HOOKUP”
SORRY ABOUT THAT
Hi Greg,
Ok… so we’re talking about 420 watts of solar power. (As long as you get 4 solid hours of good sunlight per day, you’ll get your 1500 Watts.) 210 Watt Solar panels are probably setup to charge a 24 volt battery bank : So you need a 24 volt battery bank. (Connecting batteries together in series means you add up the voltage but the amps stay the same, connecting them in parallel means you add the Amp’s of the batteries but keep the same voltage.)
For the charge controller, it makes no difference how many panels you have it’s all about how many amps it puts out. So a 24 volt 420 watt panel (again, it makes no difference that it’s really 2 X 210 watt panels) gives you 17.5 amps of charging power. (Amps = Watts / Voltage) So any charge controller that can handle ATLEAST 18 amps will do.
For the batteries : Always get deep cycle batteries. You’ll need to connect together for a 24 volt configuration. (So Lets say you get 6 volt 225 amp hour batteries, you’ll need 4 of them connected in series to get a 24 volt 225 amp hour battery bank. If you get 8 of them, you’ll have 2 strings of 4 batteries connected in series, and those 2 strings will be connected in parallel to give you a 24 volt 450 amp hour battery bank. )
For the inverter : It really depends on the maximum amount of power that you will take in a single shot. You’ve said you’ll need about 1500 watts per day, but haven’t mentioned how much you need simultaneously. Whatever that amount is, that’s the size of the inverter you need to get.
As far as the size of the wiring goes, there are more details I need. What will the distance between the solar panels and the batteries be ? What will the distance between the batteries and the inverter be ? Once I know that, I can answer that question.
Hope this helps !
Sorry for the delay in answering, I’ve been flooded with solar power questions recently !
DigitalMind
Neil : Although you can technically charge a battery bank via a car, a generator is MUCH more fuel efficient.
Jenny : Everything you said is correct. The solar panels fill up the battery bank, which is connected to the inverter. If you already have a battery bank and and inverter on your boat, then all your missing is the solar panels and charge controller. If you have a 12 volt battery bank, make sure the solar panels you buy are made to charge 12 volt battery banks and not 24 volt battery banks. (Most solar panels above 100 watts are meant to charge 24 volt battery banks)
The charge controller goes between the solar panels and the batteries, and basically stops the solar panels from OVER charging your batteries. (Unless you have WAY less panels than what you actually need, you MUST have a charge controller)
Feel free to send more questions this way !
DigitalMind
DigitalMind,
Yes, you are correct, I am try to setup a solar farm. I would like to have as much power as possible.
Thank you.
i love your page and i hope to tap your knowledge at some point soon… i have been trying to figure all the the technicalities of a solar system (confusing)….
i live in rainy washington state, and i want to run the entire cabin on solar… propane cooktop and three-way (ac/lp/dc) r.v. fridge i think….
the most important thing to me is instant hot water due to cabin size (under 200 sq. feet) so i don’t have room to spare for a hot water tank…. i’m only guessing that these things are power monsters… what are any other suggestions for a hot shower for two people a day….
i am willing to go 12v for all lighting, but i need serious power for 42″ lcd tv 3 hours a day and destop computer for my video editing job5 hours a day with a 700 watt power supply… so i’m prepared to put up 10k or a little more… is this even feasable or am i gonna need a 40k setup or something ?
thanks
Hi DigitalMind,
You re doing a great job of sharing your knowledge with so many people. I would like to know, how much cost one could expect, taking into account everything, if I needed 1Kw/hr of solar panels. Thats pretty much all the bare essentials in the house minus a few. And would there be a difference if I just bought solar cells and made the panels myself? If so how much do YOU think?
Thanks.
Aditya
I have a project that needs 2200 watts of continuous power 24 hours a day. 60-70% of the power to be used during daytime, 20-30% at night. The initial start-up will be the most draining as compressors, pumps and motors are involved, however, once started power usage will be at a minimal.
Project will be in Hawaii so sunshine will not be a problem, panels will need to be mobile as well as all other equipment. that’s needed.
My last class on solar was 11 years ago. Things have changed, besides, it was solar for homes.
I would really like to be able to use the new trailer mobile units, or the panels that will roll up……any help you can offer on what I will need would be so great! Thanks!!!
Hello,
What a great learning site!
My wife & I are new to solar energy & just purchased a 9.3 acre piece of rural property with a small 400sq ft cabin in Datil New Mexico. This place is a summer residence that we will be using full time – year round. It is already set up with propane stovetop, new propane fridge, propane 6 gallon water heater & we will be installing propane heaters.
It also has:
(3) 15w solar panels
4 amp 12VDC charge controller
home made volt meter
(4) Optima Yellow-Top Gel Cells – 120 Amp reserve capacity
& 1000 watt inverter
This system will be used to run lights, a radio & an occasional appliance if possible – not much power usage.
We will be adding a small 100-200sq ft shed/building strictly for our internet business/office which will include running our laptops, a laser printer, satellite dish & receiver, an office light & thats about all the essentials…
The laptops will run about 4 hours per day & the 2 combined use about 155 watts per hour – I believe if this is the correct way to put it. The laser printer uses 1032 watts & will be used an hour a day. The satellite we are not sure of as it is not yet installed & also will be used 4 hours per day. Office light rates at 23 watts per hour, to be used 4 hours per day. This is the basic usage…
NOW – being we are both trying to understand what we need for power, we are asking what you might recommend for adequate power. Also would it make more sense to add to the exisitng system as it might be more efficient or if it doesn’t make a difference would 2 systems be fine?…
Thanks for any help as we need to figure this out as we will be moving there sometime soon! Jonathan
Hi Jonathan,
it’s good that you’ve taken the time to calculate what you think you need and to mention what you now have. It makes it much easier for me to answer you questions.
Here’s how we simplify things – You need power for :
155 watts X 4 hours for Laptops : 620 Watts per Day
1032 Watts X 1 hr for Printer : 1032 Watts per Day
23 Watts x 4 hrs for Light (Are you sure about this,
or is it 23 watts per bulb?) : 90 Watts per day
75 Watts (guess) x 4 hrs for Satellite Modem, and Router : 300 Watts day
Which Means you need a total of 2042 Watts per day that you need.
Once we know this number, we figure out how many Solar Panels you need to top off your battery bank.
How much sun do you get per day ? I’m gonna guess 10 hours just to be safe. So 2042 Watts needed divided by 10 hours of sun time to get it, means you must generate about 220 Watts of power per Hour. You currently only generate 45 Watts with what you have.
I need more information to give you more information. Are your (4) Optima Yellow-Top Gel Cells – 120 Amp reserve capacity batteries 12 volts, 6 volts, or 24 volts ? Also, I don’t suppose you know if they’re connected in series or Parallel do you ?? (What does the homemade multimeter usually read ? Close to 12 volts or 24 volts ?)
What are the existing panels being used for right now ?
Feel free to send any more questions this way. There’s also a set of e-books that I placed the link too in the bottom of this blog post that has tons of helpful information that can compliment what I explain to you here.
Thanks for the fast reply DigitalMind!
We are currently in Florida & only moving to the property in July/Aug so I must email the owner any questions we have…
He told me that the batteries are 12 vdc connected in parallel. The meter is lowest in the morning at 12.0 to 12.2 and has maxed out at a high of 13.6.
As far as the sun index I asked him to verify & he gave me his input:: “We’ve only spent time there in the summer months, meaning max sun. Trees haven’t been much of a factor with the high sun and during those months, usually 7 hours, however, probably 4.5 to 5.0 for max charging. Keep in mind that during the hottest summer months it’s called monsoon season, with some rain most every day. Sun is best in the morning on those days.”
Question DM, If the panels are working whenever there is ANY direct sunlight I would imagine that any given day of full sun would create more than 7 hours of sun correct?
We are thinking we may downsize the usage by only using one laptop at a time to start as we want to keep the cost of upgrading the power to a minimum if possible. With this in mind here are the changes…
65 watts X 4 hours for Laptop : 260 Watts per Day
1032 Watts X 1 hr for Printer : 1032 Watts per Day
23 Watts x 4 hrs for Light (this is correct): 90 Watts per day
75 Watts (guess) x 4 hrs for Satellite Modem, and Router : 300 Watts day
This existing system is in the cabin & during the daytime we won’t be using much power as the lights are 12 volt (with cigarette lighter plugs in-wall next to the 110 outlets which is cool) & we really won’t have anything else running. So that allows us to calculate the (3) 45 watt panels into the equation… Is this info sufficient to help come up with a calculation to how many & what type/style of panels we should run? Thanks!
Hi Jonathan. It’s great that you’re able to get these details, they’re very important !
The Rating of the Solar Panels are usually based on having DIRECT sunlight. Even a single branch in the way, the slightest bit of shade on just one part of the panel, will drastically bring down the charging power. You should use the numbers he gave you: 5-7 hours of PEEK sunlight per day. (although that does seem low for Mexico, I always thought there would be LOTS more sun there)
If you have 4 12 volt 120 Amp batteries connected in Parallel, it means you have a battery bank of 480 amps which is (480amps x 12 volts) 5700 Watts of power in your battery. Since you should only use the top 40% (lots of people suggest never discharging more than 20% !) you have a total of 2280 Watts to play with. (in order to keep your batteries alive as long as possible)
From what you’ve told me, you need 1800 Watts of power per day. So, your battery bank is basically perfectly sized for that load as long as you are able to recharge your battery bank everyday with enough solar panels.
SO, once again, you need atleast 1800 Watts of power to go into the battery bank everyday. 1800 Watts / 6 hours of sun means you need a total of 300 Watts of Solar Panels. (You currently have 45 – so you need 250 watts of MORE power)
If I were you, I’d try and find a way of not using the printer so much. That’s the big power hog here.
You WILL need a new charge controller to support all these extra panels.
You WILL need a new inverter to support the load of the printer. (You said you had a 1000 watt inverter, but the printer alone will pull 1032 Watts. If you didn’t have the printer, your existing inverter would do the trick)
You MIGHT need to change the wiring between the 45 Watt panels and the battery bank once you add panels. (Hopefully they’re close together – if they are close the cost is not important, if they’re 50 feet apart just the wiring can cost quiet a bit)
Here’s one last REALLY important detail you need to know. Most solar panels are built to charge a 12 volt battery bank (they usually output between 13-19 volts) and others are setup to charge a 24 Volt Battery Bank. (They output roughly 25-33 Volts) You CAN NOT use 24 volt panels to charge your 12 volt batter bank. HOWEVER, most panels over 100 Watts are ALWAYS 24 volt panels. I’m telling you this because if you find a great deal on a single 250 Watt Solar Panel, it’s probably a 24 volt panel and is no good for you. Instead, you’d need a few solar panels that ARE 12 volts. (Like 3 more 85 Watt 12 volt panels) You CAN switch your system over to 24 volts, but then you’ll need to double up the batteries you have (4 more batteries) OR you’ll need to re-wire the existing batteries but then you only have half the power that you do with a 12 volt setup.
Hope this isn’t discouraging you, it sounds much harder than it really is when you’re first learning it. Feel free to send more questions this way, and I’d love to see pictures of your setup once you move there !
Well we are researching laser printers that are energy star to hopefully get less of a power hog! If we do need an upgraded inverter, what would you recommend – size, brand? As far as panels do you have any to recommend? We don’t care if it is one panel or more, doesn’t matter – just most reasonably priced & good quality… I will contact the seller about the distance from panels to bank.
Thanks!
I want to run a device that is 230 volt, 18 amps, 8 hours a day, with a 8000 watt inverter, how many panels would I need?
Hi…I just read all your posts regarding solar panel set up and I am fascinated. My husband and I just purchased a travel trailer. While we are always planning to camp with hookups, I want to be prepared for emergencies. I don’t care about the lights, water pump, a/c, etc. but it would be a MAJOR problem if we had no power left and could not get the slide in. Someone suggested getting a few solar panels to do a “trickle charge” and that way we would always have enough to handle those emergencies. Keeping the fridge going would be an extra perk. Where do I start?
hello thanks for the great site…. i have a barn that has no power the main line was cut. breaker box is still there along with the 6 60 watt lights and 3 flood lights outside ” 2 lights per flood” since im not out there much and i dont need to run all the flood lights only thing thats gonna be on 24/7 is my trickle charger on my harley.. whats the cheap route and how many and watt do you think ill need i have a inverter already and ill be lookin at deepcycle batts soon also whats a good cheap charger so i dont over charge….as of right now i run a 1000w gen and it runs everything just fine… but its a hassle to put it out side and start it etc etc im in ohio so we’ll shoot low for 5 hrs max charge daylight….
thanks again 73′s
David KB8TCV
ps… you should try QRP HF while camping i do alot of psk31 while in my truck and camping…i have a acer one very small laptop yaesu 817 and rigblaster plug and play for mobile and rigblaster plus on my home station on my kenwood hf rig
@ Nyleen : How often do drive the travel trailer and how long per year is it connected to mains power somehow ?? Solar panels are expensive, and you COULD trickle charge them with a few solar panels, but you might just be better of getting a battery bank and use the mains and / or engine of the vehicule to charge the batteries while they’re connected. Much simpler, much cheaper, just as effective. Let me know and I’ll send you the appropriate links !
@ David : Thanks for reading !
It really all depends on your power consumption, how much power does the trickle charger for your Harley take ?? What is your 1000 watt generator currently being used for ?
Since you’ve mentioned Ham Radio and that you’re from Ohio, I’ve got a question for you. Is your state jam packed with Ham’s or something ?? For the last 2 years in a row, I’ve noticed that during the field day we always have twice as many contacts in Ohio than any other state. What gives ?? I’m seriously considering driving down to Ohio (From Montreal, Quebec, Canada) one day for fieldday.
As for the camping part, I make it a point not to try and not operate any electronics on my camping trips. No music, no Ham radio, no Cell phone, no laptop, nothing. Just the sound of the wind, tree’s, and the evil racoons.
73′s de Jason, VE2RIF !!
from what im reading online it does 12W current draw and .750mA output but its a battery tender so its not on all the time.. the generator now is running the lights when im out there…i just want to be able to flip a switch and have lights instead of the loud gen running while im out there….
yes there are alot of hams in ohio i wouldnt come down for fieldday i would come down for hamvention http://www.hamvention.org/index.php its 1 of the largest hamventions in the usa iv met people from all over the world there….we normaly go down fri and sat 1 day for the fle market, other day for the inside show….there was alot of solor panels out there this year but not knowing what i do now im glad i didnt buy any….
David KB8TCV
We have a 2500 sq ft house located near Myrtle Beach SC. We would like to convert as much of our house as possible to solar. We use propane for heating water and are planing to change our dryer and stove to propane. We are considering a propane or 3 way fridge. We will need air conditioning in the summer months. I doubt that we will be able to go off-grid, but would like to wean ourselves as much as possible from the electric company. We have an unobstructed roof to place panels on. How many panels would we need? We are a family of two. Presently, we are using a pasive solar system to heat our swimming pool and use it very little because it heats the water so quickly.
How do I submit a question?
This may sound like a lame question, but…
I am wondering if I have to keep the same amp batteries in my battery bank or can I have batteries with diffrent amp ratings, and still run them parallel? ( Example. I have a 12V/7ampHR battery and want to run it in parallel with a 12V/12ampHR battery, for a total of 19ampHRs.) I know is solar panels as long as the volts are the same, the amps don’t matter. But what about batteries?
Hi, Im really want to get started converting to solar energy but I want to start small . I would like to run my water on solar first . I thought I could use a 3000w inverter a panel and a deep cycle battery . Can you tell me everything I need exactly . I seen something about a device that keeps the battery from being overcharged . Do I need to take the water heater off grid ?
Please contact me as I am interested in having you as a guest on a show I host on Monday evening, 8-10pm Central. My show that I co-host with Michelle is titled “The Survival Corner”.
Thank you
Can I run a central air condictioner on solar power?
I don’t care about the rest of the house, without the air on my bills are only about $45.00 a month. I live in Mesa, Az. Lots of sun, over 300 days a year.
Thanks,
I WANT TO RUN 4000 WATTS OF LIGHT FOR UP TO 18 HOURS A DAY FOR 3 MONTHS HOW MANY PANALS DO I NEED?
Way too many. Whatcha growin ?
GROW ROOM
@Brian : Running an air conditioner on solar is possible, but very ineffecient and expensive.
HOW MANY PANLES DO U NEED TO RUN A 1000 WATTS
HELLO
WHAT DOSE 1000 WATTS ADD UP TO IN KILLAWATTS
you need 1000 watts worth of panels to run 1000 watts of electricity.
Im putting in 5 200watt solar panels I also have two small wind turbines running. My question is I have 48v forklift battery and an Xantrex 6048 inverter would I run the solar panels in a series or parallel them? My hope is to use what I need and of course sell back to the grid any excess power. Thank you
My question is will I need to buy addition equipment to take an RV particially off the grid, and run the AC off the grid. Materials I have on hand:
4-15 watt panels 22 v dc output
1 – 7 amp voltage regulator 13.8 volts cut-in 14.2 cut-out
1 – 5,000 watt inverter /10000 watt surge (12 volt in-put)
1 – 110 volt charger 16 amp output to battery pack (emergencies)
4-675 amp deep cycle battery (tied in parallel)
RV can run on 1,500 watts per day with the AC tie to the grid .
Per article, I will need to purchase 315 watts per hour on the solar for a total of 375 watts per hour. I plan to purchase 1 X 215 watt and 1X100 watt panel.
hello digitalmind,
i have a house in norhtern haiti, on average we have abt 8-10hrs of sun light. i have a fridge(355kwh/yr = 355000 wats/yr = 970watts/day 40watss/hr), TV(50watts/hr) 3lights(18watts) 2floodlight(25watts) laptop(40) and 50(watts for misceleanous stuff) many of these things will not be on throughout the day beside the fridge which will be on the whole day, i will say on average hrs for everything. and please correct me if im wrong with wattage estimate on the fridge(calculation) but everything else i went to check at lowes and homedepot. so my delay usage looks around(5770)…public ectricity comes on abt 18hrs/wk but i dont mind not using it at all, i will also have a 15kw generator on hand which i don’t mind using for abt 4hrs/day if needed to charge the batteries i will have in the setup. i would like to know what kind(size wise) of INVERTER do i need, how many battery(good ones but not too pricey) n solar panel do i need to keep all these things on running with the estimate of wattage usage i gave you. Thanks in advance.
BTW: i am so glad you have this website it is so useful, GOD BLESS YOU!
first off id like to say thanks to the author…
hi guys according to my electric bill i run about 614kw/h per month (average of 12 months) thats about $4-5 a day here in the Philippines
we get a lot of sun and wind here my question would be would it still be wise to invest in some sort of alternative energy system, just to get power independence and go green, what is the cheapest system or hybrid system that could sustain these power requirements?
btw i started out doing about 800kwh/mo. i replaced all the old lights with CFL’s and got LCD instead of picture tube tv/monitor, got a new energy efficient A/C unit (645watts i think, had an EER of 11.7 if i remember correctly) and ref, switched my old pc to the small compact asus EEE box (does an amazing 11 watts only), even my home theater pc got a make over put in a 45watt low power amd cpu, i guess it all adds up
sorry, to correct my comment
the asus eee box actually does about 20 watts – still amazing btw
Hi Timmy.
Welcome to TechieNATION, and good job on cutting down your power requirements !! All those little things really do add-up.
Converting an existing house that is used to being on the grid is always very expensive. Solar power is great, but it’s very costly. I find it more useful for when you’re in a place that has NO power. (like cabins, RV’s, boats, etc) Changing your lifestyle should be the first step.
With all that said, here’s the bad news :
So you’re using 614,000 Watthours per month.
Divided by 30 days in a month means you need 21000 Watts per day!
Lets say you get 8 hours of sun per day, it would mean you’d need 2625 Watts worth of solar panels. Average price of solar panels is 5$ per watt, which means an investment of $13,000. If it costs you 5$ of power per day being on the grid now, it will take 8 years for you to actually start saving money.
Wind Power is cheaper, and can run 24 hours a day depending on how much wind you get. I’m un-able to make these calculations for wind generators though. (You’d still need a wind generator capable of making atleast 2625 Watts per day – I just can’t tell you what the price and the size generator you’d need) The prices vary a lot depending on if you’re buying a generator or making your own.
Hope this helped, send any more questions this way !
Great site thanks for all the info…
as i sat and read thru all the posts it seems to me that the biggest problem people have is figuring out what there peak instant usage is. i agree that it is all confusing but i think i have figured out a way to kinda simplify this( well at least in my mind). ok so lets give you a little background here. i live in a old duplex that has been opened up into one big house. 2 bedroom,1 bath, livingroom, dinningroom, kitchen on each side. that makes a large 10 room house. currently this house has 2 complete utility connections (2 gas,water,electric meters) when i opened it up to make 1 big house i had the utilities shut off to 1 side! i do not use 1 of the kitchens so there is no major draw of electric to 1 side(just lights radio and a few ods and ends) now with this being told this gives me two breaker boxes! and i think this could be a big key to a lot of people. what i plan to do is this! all the major appliances will be hooked up to the side that has the electric from the power company. and everything else wall outlets lights ect will be run off the grid. my electric bill for last month was $75.00 US. so i figure that i will cut my electric bill in half at least. now i dont know how much other contries pay for there electric but to me if i cut it down to just $35.00 a month then that is a number that i can live with. the reason i have went thru all this is to tell people that this way i do not have to buy a large solar system, or buy a new fridge,dryer(mine is electric) . well i have chewed your ear for long enough so any comments or ideas will be welcome have a great day and be green
thank for the great info,
i live in afghanistan we have about 7 hours of sunlight in winter i am using a solar 40 V 4.7 amps/hours charging two batteries in series
i have a 24v convertor hooked up
what i use is a TV 60 watts 5 flourecent lights 20 watts each and phone chargers etc. i will say total 30 watts and the total is ( 190 watt ) or ( 7.91 Amps )/ hour and i use them all for three hours every night which makes it a total ( 23.73 Amps per night ) while i get about ( 32.9 amp ) everyday i am using 75 amp battries but somehow the batteries won’t last for more than 5 or 6 months and this is the 3rd time i am going to have to change and buy new battries and i am using lead acid batteries as deep cycle batteries are not avaialble here
please help me if you have any idea
thanks
any one reading my comment
any one reading my above comment
yes, sorry for the delay and welcome to TechieNATION. Ok, so the numbers seem ok. You use about 570 watts per day. Your solar panels generate about 780 watts per day (with 7 hours of sun), and you have a battery bank of about 1800 watts. Not bad, technically it means you shouldn’t be draining your batteries more than 33% every day. (Ideally, you would discharge even less than that though. Like 20%)
Deep cycle batteries ARE lead acid, so you need to clarify a little more as to what type of lead acid batteries you’re using. If it’s car batteries then that’s your problem. It’s normal that they only last a few months. Marine batteries are better than car batteries, but still will rarely last more than a year. Forklift batteries are amazing, golf cart batteries are great too. (That’s what I use)
Do you have a charge controller between the panels and the batteries ? (It’ll stop from over-charging, and will prevent power from “leaking out” at night when there is no sun)
thank you very much for your infor
and yes i do have a charge controller between the panel and batteries i bought a pair of the dry batteries and the only lasted for two months
actually one of them stoped working and wouldn’t even last for 20 minutes while using it
then i bought the usual car battries and they only lasted a few months and finaly i bought these lead acid batteries VOLTA you can check it at ( http://volta.com.pk/index.php?Action=ExportProducts ) the Battery type that i am using now is ( MF90D31R/L ) and i have been using them for about a month but they are imblalanced again battery A shows green indicator light while battery B shows white indicator light while i tried charging battery B in my car for a couple of times and the imbalancing will happen again and i am worried it won’t last more
please let me know
thanks again
would you mind if we used your article and credit you and the site of course for a web- site called friendly-suggestions.com. You were a lot of help– i say a 45 watt solar panel kit for $159.00 and I thought–cool–until I read your article. I feel if you’re goiing to do it-do it right. So, I’ll be saving my money and do it right. Thank you so much
@Wahid : I checked out the link. You’re still using “automotive” batteries which is a big no no. Right below that section is the “solar” Deep Cycle Batteries. That’s what you need. There’s no way around it, all car batteries are no good for solar power use. (Car batteries are meant to discharge quickly to get the engine running, and then immediately get re-charged by the vehicule it’s in)
As for the balancing issue, you’ve gotta stop using your car to charge them. Get a real 24 volt Batter charger that either plugs into the wall or into a gas powered generator, and OVER Charge them. You should be doing this once every few months. It will equalize the batteries. Although I”m not sure if this applied for automotive batteries. It does for the deep cycle ones for sure though!
What are the indicator lights you’re talking about ?? I originally assumed it was from the charge controller, but there should only be 1 light there. not 2 for each battery. What else is connected to it?! (I’m wondering if you’ve got a charge controller on each battery instead of 1 24volt charge controller for both)
Take care, send any more questions this way.
@Bonnie : Yes go ahead. As long as you credit techienation.com for it you can copy the whole article. 45 watts is a nice little start, my sisters off-grid home’s lights are powered by only 60 watts worth of panels !! (Although I admit she needs a little more)
Wahid : I also wrote an article about the kinds of batteries to use or not use for solar power. You can read it here : (if you haven’t already)
http://www.techienation.com/choosing-batteries-for-your-solar-renewable-power-system/
thanks for the info
i think the batteries should be the problem i am having since good quality batteries are not available here but i will manage to get some from abroad this time
the indicator light that i had mentioned is installed in the batteries that i bought as it shows and chages automaticaly to 3 defferent conditions
Green=Good condition
White= nees charing
Red= Battery needs to be replaced
and i have one 24 Volt relay on/off charge controller for the two batteries which is only sesitive to Volt it cuts the current from the solar to the batteries at 28.8 Volt as no MPPT controller is avaialable here in afghanistan
thanks again and keep up the good work your information is the greatest and very helpful
Hey all, I just read every post and here is my set-up
1 20w solar panel
1 30amp controller
1 2000watt inverter
3 deep cycle marine batteries..
my controller says i have 500ah and my batteries are at 65% life and currently charging.. I know my one solar panel will not do much but its all i can afford for now.. but my question is..
i cant run my 1000w single burner to cook with. i have a 2000watt continuous/4000watt max invterter and a 30amp controller why cant i run 1000w?
is it the battery life? or not enough batteries?
my ihome and little things work fine but ..
i have 500ah and cant use 1000w of power im stumped! plz help
What are the exact specs of your batteries ?
With only 20 Watts worth of panels, you should NEVER try and use that 1000 watt burner. Running it for just 10 minutes will take 8 hours or HIGH sunlight to replace the power in your batteries. (go propane) PLUS, a 2000 watt inverter will suck up power if turned on, EVEN if there’s nothing plugged into it !
Get a volt meter and check the voltage of your battery bank, and get back to us telling us the specs of your batteries. You said you had 3. So I’m assuming you have 3 12 volt batteries hooked up in Parallel, how many amp hours per battery ?
thanks for the fast reply..
the 2000wat inverter takes takes 0.3v with nothing pluged in it sucks.. but o-well
the batteries are deep cycle batteries 3 X 12v wired in parallell at 500cold cranking amps each.
total output voltage was 13.3v
realistically i am only going to be running under 500w 2-3 days a week for only a few hours at a time, for my computer and small fridge in the summer.. so when i get the cash of coarse im going to get another 20w panel.
but i do have a 750watt burner as well at it wont turn on either.. im just trying to cook some meals while camping in the winter and it would be nice!
Big loads like these (on small battery banks) are common issues. Why not use propane for this ? What brand and model number is your inverter ?
An inverter that uses .3 volts (for 12 volts) while turned on means it uses 86.4 Watts per day if turned on for 24 hours a day. With 20 watts of panels, you would need 4.5 hours of quality sunshine per day just to keep the batteries at the same level. Is your inverter only turned on when you need it, or always ?
only when used… and i thought of that same problem so i have 2 inverters really… the 2000w that takes 0.6v actually my bad.. and i have a 800w as well.
i mostly use the 800w i only purchased the 2000w inverter because i need to run that 1000w burner.. or deal with gas/stove option (im inside a vw bus) so i really want to cook with electric aplliances..
so ideally i want to just use the 800w..
and when i cook for 10-15 mines 2-3 days a week using that 1000watt
should my batteries be at 100%? cause right out of the store im getting 60% charge.. thats why they are on the trickle charger now..
so do i need more batteries ?
heres a link to the inverter:
http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=200416407206&ssPageName=STRK:MEWNX:IT
digital ming,
i have a question
i bought a solar panel 4.58 amp at 18 volt open circuit
i am going to make a special invertor that has 18volt input to match the solar voltage and i won’t use a battery bank i will connect the convertor direct to the solar panel so i will be only using it during the sunny days
the question is ( how many watt AC ) will i get from the convertor
i was wondering if i might lose some watts as the convertor might use it but how many watts will i lose
please let me know if this will work as i am planning to make my project bigger by adding more solar panel to the system
watts = volts * amps …
however your solar panel is a 12 volt panel, not an 18 volt. It will give 18 volts when nothing is connected to it, it’s normal. (confused the hell out of me the first time) so a 12 volt panel * 4.5 amps mean you’ll be generating 54 watts of power during peak sunlight hours. I’m not sure what you plan on doing with it. You can turn on a couple of light bulbs, but then again, it’s sunny outside when you have that power available. What is your project ? What are you trying to run only when it’s sunny outside ??
Digital Mind… did you look at my inverter? do i have enough batteries? will i ever be able to run 1000w?
Hi Robert. So you’re boondocking ah ?
I don’t think the problem is the inverter. Although it might be. I’m not sure how much start up power your burner takes. Some appliances that are rated at 1000Watts can easily take 4000 watts at startup. (Just for a few moments)
65% life for your batteries is not good. You generally never want to discharge it more than 30%, and even then it should get recharged quickly.
Most Boondockers have a little setup so that when the vehicule is running, it starts charging the batteries that are part of your renewable energy system. (Basically it’s a kind of relay that will let power from your vehicule charge your battery bank when the car is on, but will disconnect it when the car is off in order to not drain the car battery)
In the end, I’m still suggesting you go propane for this. If not, get an electric 12 volt stove so that you don’t need the inverter at all. ( http://www.globaltrucker.com/products/Burton_Table_Top_1800_Watt_Induction_Cooktop_Stove_Top_Cooker_w_FREE_SHIPPING-699-22.html ) Your battery bank does have enough power to run your stove, but you don’t have enough solar panels to keep your batteries charged, ever. (I seriously doubt you’ll ever see them anywhere between 90% – 100% charged with only a 20 watt panel). In a way, you’re slowly killing your batteries by not charging them.
My small solar power install in Kingston had a 225AH battery bank, and 60 watts of panels, and the panels BARELY charged the batteries. A generator was used about every 45 days to equalize them and get them properly charged. (Although they lasted a year before needing to do that) The 60 watts of panels was just barely enough to keep the batteries alive. With a larger battery bank like yours, you’d need even more panels just to keep the batteries as-is. (Even with nothing plugged into them)
DigitalMind
Get a volt meter and check the voltage of your battery bank. (Not the individual batteries, the whole bank) and let me know what it’s at.
the controller says 13.3 volts at 500ah. and i cant get them over 63% charge even with a trickle charger plugged in my house and theses batteries are brand new.
its weird.. if i watch the controller the batteries range from 63-89% and then stays at 63%
where can i buy this relay to connect from my car battery to my battery bank?
i guess i will have to use propane for cooking but i still need to use about 300w for other things.. so i should get atleast one more panel then? or should i ditch one battery and just use 2?
That’s weird. At 13.3 volts you should be at almost 100% !!! Can you check with an actual volt meter ? Also, can you send me the link to the charge controller you’re using ?
As for everything else, it just comes down to this :
How often do you drive that vehicule ? It might be better just to keep the 20 watt panel to trickle charge the batteries for when it’s sitting there, but use the vehicule for the REAL charging of the batteries.
If you don’t run the vehicule much, then I would suggest getting more solar panels and ditching one of the batteries. (Which sucks since solar panels are SOOOO expensive)
AND .. if you really don’t want to use propane, try a 12 volt stove. Google it, there are lots. Truckers use them a lot.
I will look into that relay thing and let you know …
I found this :
http://www.hellroaring.com/bic75150.php
In the end, all this is is a way of running a wire from the car battery (or alternator) to your other batteries. TECHNICALLY, you could run wires youself between the two, and make sure they’re only connected when the vehicule is running. The point of this battery isolator is so that you never need to disconnect anything, and it automatically feeds your Renewable Energy system batteries when the vehicule is running.
i could just use jumper cables… or is that bad? i would only use that method probably once or twice a month.. and just have to get some more panels i guess..
you COULD do that, but that would mean that when you’re charging your batteries with the car the car is just sitting there idling. Ideally you would be charging it because you’re driving around. PLUS, more power will go by having the engine throttle a little …
didnt see the other post up there my bad..
ok i used a volt meter and got 13.03v .. so should i ditch one battery still? and buy realistically another 20w panel.
here is my controller: http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=230390463526&ssPageName=STRK:MEWNX:IT
and i drive the bus every day. .but im planing a trip to canada/alaska from califnoria where i live.. but im going to be parking and stopping for weeks at a time most likely to record music in various forests etc. so i wanted the panels to power up the batteries while im sitting.. and the car can run while im going from place to place i guess..
if i cant use jumper cables.. what wire do you recommend for going to my car battery to my battery bank
now that i think of it.. i should get power from my car engine. its 40 years old with old school generator style.. no alternator. so id rather use a small generator.. which do you recommended?
*shouldn’t
I’m no mechanic, but I don’t see that being an issue. If your car has a 12 volt battery SOMETHING is charging it.
As far as picking a generator, that’s pretty tricky. Are you plannng on carrying it around with you in your vehicule ? Is there room for it ?
Obviously, you would want one that’s small and quiet. What it really comes down to, is how many amps can it output at 12 volts. Lots of generators have 12 volt outputs, but most of them are very low amperage compared to the power of the generator on 110 volts. So then you would also need a battery charger, to go from the 110 volts back to 12 volts. If you can find a generator that has a 12 volt output that is equal too or higher than the highest powered 12 volt battery charger that runs on 110 volts, get that.
I’m still a little confused that you can’t start your burner though. If your batteries are at 13 volts, that’s normally considered 100% charged. (Although some 12 volt batteries do go up to 14 volts)
It might be interesting to monitor the voltage on the batteries as you turn on the burner.
Id just rather not mess with the orignal set-up of the bus engine. If i purchased a small generator like this one:
http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=140374179841&ssPageName=STRK:MEWAX:IT
then i could run the generator ONLY when im cooking. that generator has a battery charger at 10amps 12v so i could charge the batterys while im cooking. and the rest i can leave up to the panels. sound like a good plan?
I will be using about 6500 watts of power a day, how many solar panels and batteries would i need to supply this?
Hi Gone Green,
this is a good question, yet one that I was hoping my post above would have explained. If you need 6500 Watts of Solar Power per day, the next number I need is how many hours of sun you get on average per day. Lets say you get 5 solid hours of sun per day on average for the whole year. That means that you need to make 6500 watts of power in 5 hours. So 6500 Watts divided by 5 is 1300 Watts per hour. So you need ATLEAST 1300 watts of solar panels. So 1300 watts of panels at an average price of 5$ per watt means $6500 worth of solar panels.
Since you never want to use more than 30% of your battery bank, you’d need a battery bank of about 26,000 watts. (That way, if you go a couple of days without sun AT ALL you’ll still have power)
Feel free to ask more questions, welcome to TechieNATION !
sorry i hadn’t read all the post before i asked my question. Where i live we average 8 to 10 hrs of sun light, i can figure out the rest thanks for the help. I’m sure i’ll be back with more questions
Hi
I am looking to do the following
I make ups aps varries from 500 watt to 5000 watt
I use a transformers with the pwm board and an automatic battery charger
I need to charge a 12 volt with 200amp acid battery using a solar cells
how many cells do I need and where I can find them
thanks
Hi, DiditalMind!
Weird question you may or may not know.. My hubby and I are building a house and trying to gather info to build our own solar panels and systems.. The county folks say the only requirement we have to pass for electric is to have at least 100 amps to the house.. (we aren’t required to hook up on grid! woo hoo! They’re more expensive to hook up to than building everything! $19,000, PLUS monthly fees! EW.). My problem is this.. I’ve seen amps referred to with batteries, which makes them seem more plenteous, but I’ve also read to them refer to amps through panels.. Which makes it seem like we’ll need LOTS of panels to get up to 100 (also read that going for 200 amps is better). Do you know what exactly folks refer to when they say a home needs to be powered by at least 100 amps? (to me, sounds like batteries’ worth of amps but I don’t want to mess us up..)
We’ll be using geothermal heating and cooling, but will be using a fridge on solar (yes yes, I read that a 12v fridge or propane would be best, but we’re trying to figure how to run EVERYTHING but heating/cooling by solar..) We don’t have numbers for appliances or anything yet as we’re just trying to figure out the amp thing so we can write up a plan to submit to county.. Just wanted to see what you had to say about that, and see if you had any thoughts on everything else!
thank you so much–Reading what you’ve said thus far has been a much bigger help than pretty much everything else I’ve found:) On top of the above, just need to figure out all the bits, pieces and workings of the whole home solar caboodle.. The challenge is fun, but they call it a challenge for a reason!!
THANK YOU SO MUCH!!!!
Meg in VA–Good sun, good hills:)
Hi Digitalmind!
Please, i have 12V/24Volts Option solar Panel of 102 Watt.I could get the 24Volts Out put, whereas 12Volts is Ok?
Here is my question.. I have 12 100 watt solar panels and about 4 hours of sunlight a day.. I live in a rural area and a local electrican suggest i need 32 deka L16 batteries . 1 outback fm charger controller , 2 outback nfx3524 inverters.. Is this a little extreme, if all i can get is 4800 watts in a 4 hour period.? What might your suggestions be.? thank you.. mike
i live in wisconsin and i am always camping on the river and i need to find a way that i can keep my phone laptop and possibly boat battery charged for days on end i have searched for solar panels and i am wondering what to get i am mostly looking at a solarroll or something flexible or portable like that and i need to know what power to get and other things like that your article has also been a great help.
Hi from the rainy UK
Just want to say what a great effort is being put into this forum.
I have a large RV and have recently aquired 2x12w Solar Panels.
I want to run a conditioner charger from a 400w inverter to charge/maintain my RV batteries.
The conditioner charger is a 101w device but where we dont have many hours of sunlight, the inverter will drain my batteries out of sunlight hours – Do you know of a method to run the system for only several hours a day. The RV isnt kept where I live so I cant attand to disconnect the system daily.
Also, does the set up sound reasonable – 24w Solar to 12v Battery to 400w Inverter to run a 101w Device?
Many Thanks
i have an 1800 watt honda generator, can my deep freeze operate with this generator?
First off what a SUPER site for Solar info
I commend you !!!
what i would like to Know and not been able to find out is
I have 2400 watts of Grid tie Inverters ( 8 -300 watt stackables)
can i put a standard pure sine wave inverter on line with out grid power and stack my 2400 watts of gridtie inverters with it
(PLEASE NOTE THIS WOULD BE FOR USE AS BACKUP POWER ONLY WHEN LOSS OF GRID POWER USEING A TRANSFER SWITCH )
LOOK FORWARD TO YOUR RESPONSE
Dale
Let me start with,the information on this site by the techies is unbelievably good.
I tried using your calculator and think I screwed up. I use roughly 30 kwh a day.I would like to simply cut my bill in half,or better,if I were to build panels myself and only use professionals for the grid tying procedure would this be cost effective for me. I would love to help the environment in any way I can.I live in the Upper Peninsula of Michigan so we only get about 4 to 6 hours of good sunlight,on average. Thank you in advance for sharing your knowledge with us.
hello there,
i plan on using solar for my garage to run my lights. i do auto body work so lots of lights means no shadows for painting and what not.i have roughly about 1000 watts of lighting im in there for prolly 16 hrs a day . so what do u think i should do for that what size system i live in the north east. summer time i get maxx lighting but winter in jan feb prolly like 8 hrs of sun on a good day so can u help?
I can help, but you might not like what I have to say.
Ok, well 1000 watts of light seems like a lot. What kinds of lights are these ? The first step would be to replace them with something more efficient, like fluorescents. Lets just say you ACTUALLY need 1000 watts of power though for 16 hours a day. This means you need 16000 watts of solar power every day. 16000 watts / 8 hours of sun means you need 2000 watts worth of solar panels. So 2000 x 4$ per watt (average price) is an $8000 investment in solar panels. Then you’d need batteries, a charge controller, an inverter, fuses, wiring, a mount for the solar panels. Easily an extra $1500 ….
well the lights are fluoro’s already. would it be better to build a bank of alternators run by an electric motor into a battery bank so really it would in theory power itself and create the electric i need?
?! What ?!?!?! You want to use an electric motor to create more electricity ? You can have the best setup in the world, but there are always losses. You’ll use more electricity to run your motor than what you put into your battery bank. Maybe I’ve misunderstood you, but the bottom line is that there is no electrical appliance that will generate more power than what it uses. The day that happens, it’ll be a huge breakthrough.
How many fluoro’s do you currently have ?
i am currently using 24 8 ft ballasts with 2 lights per ballast @ 60 watts each light its a big shop thats not including compressor and all that stuff. i was wondering with the alternator setup i did some research into it there was a few ppl that seemed to succesfully do it. just another idea electricity sucks lol…
Hmm, that is a pretty big place. It might be worth the $10,000 investment in the long run. (I assume it’s an actual business and you’re not alone in there?) The people that have these so called setups that create more electricity than they use are frauds. I’ve seen lots of them myself. Still, I wouldn’t mind getting a link to what you were looking at just so I can prove my point.
Actually, now that I run your numbers, it seems like you use 2900 watts of power for your lighting !! (60 watt tubes x 2 per fixture = 120 watts, x 24 fixtures = 2880 watts)
im a very hopefull person u know… there is tons of fraud crap i kno that… i do kno a guy who used a home built windmill with 3 alternators and he had great success but i get wind but not evryday. i have no idea how much draw an electric motor has . prolly would need tons of batteries n e how…. but i will look for the links for u. sux how the economy is right now and things r a bit slow…. just trying to figure something out on the greener side… i have already switched to safer greener auto products
It’s great that you’re thinking green. A windmill made using an alternator is a different story. There you’re using the wind to create electricity, not electricity to try and create more electricity. (If that was possible, electricity would be practically free and it would be unlimited) Windmills are more cost efficient than solar panels too. (as long as you build in yourself) Personally I don’t have the tools and equipment to build one, but I get the feeling you do.
now when ur batteries r fully charge whats the life of electric draw for them( watts per hr). i know the winter around here has much more wind than the summer so i could possibly use wind not sure what the ideal mph should b. >but if u use different belt sizes with different size pullies u could get max power out of a 5 mph wind compared to not using various sized just for theory sence. i guess i could always try it at least i would have the batteries, converter ect. so if it didnt work i would really only have to buy panels . hope im not too much bother for u just getting to the bottom of this lol. well mayb im keeping u busy…
how much wattage output do the deep cycle batteries produce(wattage per hr).?
Watts = volts x amps.
So if your battery bank is 225 amps at 12 volts, it means you have 2700 watts worth of power in that battery bank. (You’re not supposed to use more than half the battery bank capacity)
is that per hr or all that is there so if u have 2750 watts of power how long is that gonna last at a 1000 watt draw?
Yes it’s per hour. So a 1000 watt load on a 2750 watt battery bank would last no longer than 2 hours.
so how Many batteries would it take to power 1000 watts at say 8 hrs . we will go with the low end?
1000 Watts x 8 hours = 8000 Watts of batteries. Like I said earlier, you shouldn’t use more than half (and ideally 1/3) of your battery reserves, so you need a battery bank of atleast 16000 Watts.
Have you read the posts I’ve written about how to calculate all this ? It’s in just about every solar power post I’ve written.
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This was helpful, thanks!
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[...] This one is about figuring out how many solar panels you need : http://www.techienation.com/?p=24 [...]
Hello There, Im Trevor.w Bacelli,from Biloela Central Queensland Australia. I have 2 Questions , if you had a 96KW Submersbile Water Pump it is 380v and the slow start system is 400v 3 phase , How Many Solar Panels and Batteries and what Size inverter and Controller do you need to keep the Pump Operating 24 hours a Day seven Days a week 9 months of the Year, The Pump pumps 62,000 gallons per hour to a 50 hectare Centre Pivot there are 10 hours of Sunshine in the NT for 9 months of the year I was thinking Wind Combo as well but the wind speed is only 2.77m/s so I will give this a miss. —- Question 2 What do you need to Set up a 30KW system for the house and Sheds using Wind, Solar.Batteries to Run inderpendently of Grid the Farm ,Single Phase 240v , If you can solve these questions for me it will be very much Apprecated ,Kind Regards Trevor.W.Bacelli ,Biloela QLD and NT Australia.
Dear
I would like to switch on 2500W AC with rating woltage 220V during dayyime only, so no need for battereis
I would like to know how many solar panels I need and invertors if any
Thanks
Dear Digitalmind
During my research i find out that some inverter use up to 220V DC Input (Batter) and all The charge controllers that have come across are 12 Volt, 24 Volt and 48 Volt.
My question is how many charge controls will be needed if am using 19 solar panel 12 Volt each to charge the batteries and how to connect the charge controllers.
Thank You
i have my solar system partially set up i done a test and was upset either my batteries are bad or math is wrong, i hooked my wood heater up to a 350 watt inverter to see how long it would run.
my heater has 2 120 volt motors that pull 1.9 amp each which adds to 456 watts for both, i got 4140. watts of batteries it didnt last but a hour and a half. i checked my batteries with a battery checker it says they are good but somthing isnt right any ideals
lukman did you mean 220 amps and also if the charge controller you need is wwhat ever amps ypor panels are putting out.
in other words if your panel is 3 amps each on output add them together like 3 time 19 which will be 57 amps i would get a 65 to 70 amp controller or if you plan to add on i would get a 100 amp 12 volt most controllers have multistage voltage if it says 12 24 36 48 then it will except those voltages.
Hi Bob,
do you mean you checked your batteries AFTER the heater went out and they were still good ??? Why are you putting a 456 watt load on a 350 watt inverter????
yes the voltage was 12.5 without load went load was applied it dumped 10.5 i did checked the batteries some cells were low and the gravity was as well so i bought new acid and filled them and put a asprin in each cell havent went back to retest i guess i need to tonight.
but i didnt think about the wattage till you ask that 350 inverter ran them well, it didnt even give off a overload alarm and shut off. it ran the wood heater good.i did do a single battery check my 85 amp hours lasted 8 min each my 90 amphour lasted 9 min but one of my 85 ah lasted 3 min and i pulled it loose and found low acid and two cells had low gravity as long as you leave the charge conroller on it the heater will run all day but since the battery voltage goes back to 12.5 the controller stops sending power to batteries cause it thinks the voltage has topped out. the batteries isnt storing the current anymore. guess if what i done didnt work i will have to replace them they are up there in age anyway and was only used as backup.
i forgot to tell you with the inverter and the heaters i was pulling 16 amps from the batteries
i checked the batteries 2 of my 85 amphrs the gravity state of charge is of the scale thats very good, the other 85 has 1 cell that is still low and so is the 90 ah so i got them on a battery charger to see what happens.
evryone i found out that those battery checkers you can buy at the auto store is ok but doesnt tell the true story about batteries.
its best to buy a acid tester it reads the gravity on batteries it will tell you the whole 9 yards if you got flooded deepcycles its a must to have….
very interesting read to say the least, and I havent read it all. would love to chat but i do not see the link you referenced to earlier near the top left side bar. my wifes parents both passed away this year and we would like to move to my wifes old home place. the old house is in really bad shape but does have power. we were looking at setting up a mobile home there, that is untill the local big shots shot us down. It seems they have a scam going on, and a darn good one at that. they come out for a perc test for sewage tell you it wont perk but you can install a $20k treatment system that most people in this area cant afford. then if you appeal it (which i did and won) it still cost almost as much if not more. then i get a letter in the mail from a proerty buyer from up state wanting to buy our property. sure sounds like a scam to me! any way back on topic, we have water, we have power for now and could tie into the house power but figure if we did that they would condem the house so we are needing our own power. thats when i ran into this site. I defenitly agree that a gas fridge & freezer would be worth the investment, we already have a gas range, water heater, and clothes dryer and we heat with a wood stove. so my main concearn is lighting. I am not looking to power the whole house at this point, i do have a generator to run things such as the water pump or washing machine. thing is gasoline is expensive so the generator needs to be run as little as possible. for those of you out there in a simular deal i have figured out how to have water without running the generator but for about 10 minutes a day. my system is set up for 100 gallons per day. I havent tried it yet but i am 99.9% sure it will work. it is really simple to build all you need is enough pressure tanks, in my case 5 20 gallon tanks and run the generator long enough to fill them. shoot me a email if you would like to talk. kaiser_willys@yahoo.com
Dear Bob
sorry it was a mistake 18 12Volt Battery to give an out of 216 Volt, I do not mean 220amp “220 Volt”, for example if am using 30 numbers of 12Volt Battery Each, connected in series to give an out put of 360 Volt DC for an Inverter of 360 Volt DC input and using 30 12 Volt 160watt solar panel to produce an out of the same voltage to charge the Batteries.
My Question is since i can not get a 360 volt charge control “ONE” how many we be needed and how to connect them?
Thank You.
hI…I am desperately trying to figure in “kindergarten terms” exactly what i need to go buy for a “small” solar system…I am a woman and dont know anything about the many articles i have read…..To keep it simple…Is 360, 450, or 540 W solar system enough for the simplicity i am desiring….this would be a system to have on standby…(would not set up yet) incase something happens to power for a longer term would pull out and get someone to assemble….BASICALLY, i would have a small dorm refrigerator (only luxury) to keep few things cold…about 5 small 20w bulb lights to run 5hrs each day(in evenings)…and possibly acell phone charger for one or two hours…each day…long enough to recharge them..(possibly an electric tool if needed on rare occasion if should need)..which one of these systems would be enough….and based on that…..”EXACTLY” WHAT SPECIFIC ITEMS DO I NEED TO GO BUY AND HAVE ON HAND TO ENSURE THIS SYSTEM RUNS WELL!!!!!!! please help me………….if you give me a list i will get to ordering exactly what i need…..thanks a million….I can tell you know what you are talking about from your post……
sincerely,
traci
p.s. could i possibly run a fan or two for several hours a day as well? thanks only in hotter times (months)
Traci
his math is wrong. you would not get 1600 watts in 4 hrs into the battery’s there is 30% lose when recharging battery’s. meaning whatever you take from the battery’s you need to put in 30% more to get it back.
Great web page you have all answered my basic questions in one hit
Thanks again
By the way I Live in Zimbabwe and have between 10-14Hrs Of sun a day so solar power is going to be a priority :O)
cant i just look on my power bill for watt usage? its a 30 day cycle. 2536kw divide by 30…which is 85kw then multiply by 1000 which gives 85,000 watts?
Hi,
I already have an Inverter (Mercury Radiant Inverter 2000VA) and 2 – 12V of 100Amps Batteries. this gives me 24V of 200 Amps.
Summing up all my appliances at home is about 300Watts and I hope to be using solar light during the day and having a backup hour of 7 hours at night.
I do have 7 hours of sunlight everyday. Please advice on the types and numbers of solar panels to use
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Can you kindly tell me exactly what I need buy to power up my house?..I’ll needed for15 incandescent lights of 100 watts each one for approximate 8 hours a nights.(no fridge, no microwave no TV’s…etc.etc.etc…just the lights) I’ll receive between 8 and 10 hours of Sun light a day…Sorry, I am a little confusing and not to good with math.
1. How many solar panels & watts each one?
2. How many solar batteries/Ah?
3. What kind of charge controller?
4. How many watts of an inverter?..and…Etc.
Hi, i using solar cells for a street light 20W LED lamp which on for 10hrs, and i tried your calculation (CMIIW)
20W x 10hrs = 200 Watt hour, which means 50W/hr or 50WP solar cells
but somehow i tested it and 50WP of solar cell is not enough so i gotta add another 50WP of solar cells. Could you tell which part is wrong ? Thanks
hi digitalmind,
how much panels and what equipment will i need to run 2 lights,2 fans and a fridge continous? a lot of sun but no power here.
your info will be very much appreciated.
thanks
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