Battery Sizing for simple 4 LED Light Shed

[KYY]

After reading the dozens of "how to's" you would think we still live in medieval times with scientific data floating around that contradicts other sources.

I'm trying to figure out if 1 solar panel and 1 battery can support itself and what size charge controller I would need to do this with.

Here is my data and things I already know I have:

Daily watt hour usage: 4 LED 10 WATT Lights at 8 Hours = 320 Watt Hours per day of usage of the LED lights.

Battery system: 1 12Volt 100 amp hour battery (GPL- 121000)

Solar Panel: 1 190watt (Voc = 45.24) (Vmp = 37.7)

I live in SE Kentucky (region 5) which the lowest it gets in the winter is around 30 degrees F.

I want a 12 volt system

Cloudy Days to support: 2 days

Will this 1 panel that I have support the 1 battery that I have to operate the 4 LED lights that I have? And what size charge controller should I get

[Sunking]

Minimum requirements

Minimum Panel Wattage = 200 watts with MPPT, or 300 watts PWM
12 Volt battery = 125 AH
Charge Controller = 25 amps

[Logan5]

When in doubt go with the data derived by the scientific method, Other sources usually contradict that data, hence why you called other sources. Other sources, salesmen trying to get your money, Of course they say anything is possible when it is not. Dreamers, who believe they will get house power from a paralleled 12 volt battery bank, never gonna happen. Your proposed system is possible, but it will be costly, here in Florida our POCO sells 1 KWH for 11 cents, Your battery system will cost 1.00 per KWH for it's life time. If you have POCO avail, you would be better served with a non cyclical UPS system plugged into an AC powered wall charger. If you want to capture solar power you could use a timer to cut the AC charger out during the day hours. Risking cycling your batteries and shortening their life span. I am a Ham operator and have 2 battery banks, one is a custom made AC powered UPS (Non cyclical) and one cyclical solar set up. Both 24 volts. the cyclical set up requires twice the maintenance and still need regular battery bank replacement.

[SunEagle]

After reading the dozens of "how to's" you would think we still live in medieval times with scientific data floating around that contradicts other sources.

I'm trying to figure out if 1 solar panel and 1 battery can support itself and what size charge controller I would need to do this with.

Here is my data and things I already know I have:

Daily watt hour usage: 4 LED 10 WATT Lights at 8 Hours = 320 Watt Hours per day of usage of the LED lights.

Battery system: 1 12Volt 100 amp hour battery (GPL- 121000)

Solar Panel: 1 190watt (Voc = 45.24) (Vmp = 37.7)

I live in SE Kentucky (region 5) which the lowest it gets in the winter is around 30 degrees F.

I want a 12 volt system

Cloudy Days to support: 2 days

Will this 1 panel that I have support the 1 battery that I have to operate the 4 LED lights that I have? And what size charge controller should I get

You are close to having a system that will get you that 320 watt hours daily.

Sunking gave you some good info that slightly upsizes your battery and panel wattage which will get you a little more insurance toward getting that 320 watt hours.

[KYY]

Ok, thanks everyone! So.... with this said, I know there are calculations somewhere to do this or are you doing a "real life" experience of what would work? I'm just thinking there has to be an exact formula or calcuation for this with all things accounted for, which I get bits and pieces on the web.

[J.P.M.]

Ok, thanks everyone! So.... with this said, I know there are calculations somewhere to do this or are you doing a "real life" experience of what would work? I'm just thinking there has to be an exact formula or calcuation for this with all things accounted for, which I get bits and pieces on the web.

I'd respectfully suggest you consider rereading Logan5's post for guidance how to proceed, and then do the search the harder but more productive way.

[Sunking]

Ok, thanks everyone! So.... with this said, I know there are calculations somewhere to do this or are you doing a "real life" experience of what would work? I'm just thinking there has to be an exact formula or calcuation for this with all things accounted for, which I get bits and pieces on the web.

There are calculations, you just did not bother to look. Try reading this and answer your own questions.

[KYY]

Actually, Prior to my question, I did read that link that you wrote Sunking (3 times and just now again).... but I came up with a different answer.

[KYY]

So with just the panels alone, I get 106 watts required for what I need. I don't see where your getting 200 watts needed.

I've done the math over and over.

So for SE KY, with 320 watt hours per day used, I take that and multiply by 1.5 (Fudge factor/loss) for the MPPT controller, which I'm not up to 480 watt hours.

Take 480 watt hours used per day and divide by your areas sun hours (which mine is 4.5/day). So 480/4.5 is 106 watts of solar panel needed.

Am I missing something or doing something wrong? That's way off from a 200 watts needed. Thanks for your replies, just trying to understand where these numbers are calculated.