Comments on: Solar Investigation : How many solar panels do you need?

By: DigitalMind

DigitalMind — Mon, 27 Oct 2008 18:42:46 +0000

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.

By: charles

charles — Mon, 27 Oct 2008 16:39:44 +0000

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

By: DigitalMind

DigitalMind — Tue, 21 Oct 2008 21:48:03 +0000

@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 !

By: charles

charles — Tue, 21 Oct 2008 21:21:32 +0000

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.

By: DigitalMind

DigitalMind — Sat, 04 Oct 2008 13:49:34 +0000

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.

By: jimmy alan

jimmy alan — Sat, 04 Oct 2008 07:50:44 +0000

Thank you for your information .
Jimmy

By: oral

oral — Fri, 15 Aug 2008 19:51:41 +0000

i am checking ebay

By: DigitalMind

DigitalMind — Fri, 15 Aug 2008 13:43:25 +0000

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.

By: oral

oral — Thu, 14 Aug 2008 21:16:27 +0000

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

By: DigitalMind

DigitalMind — Thu, 14 Aug 2008 15:31:56 +0000

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 !

By: oral

oral — Thu, 14 Aug 2008 15:25:29 +0000

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

By: DigitalMind

DigitalMind — Wed, 09 Jul 2008 13:38:32 +0000

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)

By: Chike

Chike — Wed, 09 Jul 2008 11:45:19 +0000

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.

By: DigitalMind

DigitalMind — Fri, 04 Jul 2008 19:04:19 +0000

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 !

By: dingoo

dingoo — Fri, 04 Jul 2008 18:35:50 +0000

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.

By: DigitalMind

DigitalMind — Wed, 25 Jun 2008 16:24:03 +0000

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

By: oral

oral — Wed, 25 Jun 2008 16:07:44 +0000

great !!
by next week i will be able to tell you on my progress i will even upload some pictures if possible

By: DigitalMind

DigitalMind — Wed, 25 Jun 2008 14:04:31 +0000

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).

By: oral

oral — Tue, 24 Jun 2008 22:44:07 +0000

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

By: DigitalMind

DigitalMind — Tue, 24 Jun 2008 14:07:47 +0000

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 !