Going Solar

Â¡Niers! · Post by **Â¡Niers!** » Mon Mar 23, 2009 12:06 pm

So, this year I am bringing a 120 watt solar array with a couple 100 ah deep cycle batteries and a power inverter.
I was wondering if anyone had any idea of how much power this would actually supply (in layman's terms) for a small camp with lights, a fan or 2, and a stereo. I can somewhat figure out how long a 100 ah battery would last (I think) but have no clue how fast one would charge up with these solar panels.
So, if you have some experience with solar maybe you could share some.......please?

Thanks

klondike_bar · Post by **klondike_bar** » Mon Mar 23, 2009 12:47 pm

im not really sure how to convert amp-hours to watt hours, but id think that a 160watt panel should be sufficient.

assuming you can pull 5 ideal hours of sun a day (in reality you can probably get almost twice that), thats 800watts.

a few simple camp lights will require less then 100 watts to sufficiently light a mid-sized tent (per hour), a fan will take up to 150 watts, and a stereo will also be well under 100 watts.

in other words, if you run a stereo for 6 hours a day, lights for 4 hours at night, and a fan for 6 hours a day, you will likely need ~1000watts a day.

while this exceeds the panel, it is a VERY relaxed guess, and you will likely be able to create excess power in any case. just keep power requirements in mind when shopping for electronics.

phil · Post by **phil** » Mon Mar 23, 2009 4:39 pm

Check this Burner site:

http://www.ae-zone.org/

and look around, especially at the "System Designs" link and the lightbulb link at the top. The site is framed, so internal links are too aggravating to get to for URLs.

Also check here:

http://delicious.com/philip/power

for links to sites that provide additional information. Commercial sites (Affordable Solar, for example) often provide javascripts that let you do calculation on how many solar panels you should buy from them. :->

motskyroonmatick · Post by **motskyroonmatick** » Mon Mar 23, 2009 5:13 pm

Hi iNiers!
Computer fans draw very little power and move quite a bit of air. They do make a bit of noise but I find sometimes having the background noise helps drown out the interesting noises at the burn that keep one from going to sleep.

I have a 60W(claimed) solar setup. I was able to run a 1amp load for 24 hours a day at the burn with the battery hitting about 11volts in the morning after running all night. The battery was fully recharged easily in the daytime. I was running a 12volt 650 gallons per hour sump pump.
The next year my evaporator set up changed and that resulted in the pump needing to pump higher and farther. The 60w panel did not keep up to the higher load on the pump and I ended up charging my battery each day. I consider my setup too be about as small as one could do anything practical with. Your set up with more capacity in charging and reserve will work much better I am sure.

I like to keep everything I run off the battery 12 volt that way I don't get loss from an inverter.

mk-ultra · Post by **mk-ultra** » Mon Mar 23, 2009 7:50 pm

Â¡Niers! wrote:So, this year I am bringing a 120 watt solar array with a couple 100 ah deep cycle batteries and a power inverter.
I was wondering if anyone had any idea of how much power this would actually supply (in layman's terms) for a small camp with lights, a fan or 2, and a stereo. I can somewhat figure out how long a 100 ah battery would last (I think) but have no clue how fast one would charge up with these solar panels.
So, if you have some experience with solar maybe you could share some.......please?

Thanks

You've left out some needed info here.

To convert from watts to amps, we need to know the voltage. Is this 120 watts at 12v... or 120 watts at 110v... or?

watts / voltage = amps

Example: a 120 watt light at 12v = 10 amps

Â¡Niers! · Post by **Â¡Niers!** » Mon Mar 23, 2009 9:59 pm

Sorry, you are correct.
This part confuses me a little though.
The info on the panel reads:
Voc:23.5v
Vmc:14.5v
I don't know what either "Voc" or "Vmc" mean.
I know how to use the panels, I just don't know some of the terms or calculations other than VxA=W, and I somewhat understand AmpHours.
Hope that helps.

Sail Man · Post by **Sail Man** » Tue Mar 24, 2009 2:00 pm

Calculate your 24hr amount of amps needed and that will tell you the size of panel needed, but if you can buy a panel rated at twice the amt to account for efficiency, clouds, dust, and of course night.

capjbadger · Post by **capjbadger** » Tue Mar 24, 2009 3:31 pm

Voc = Open circuit voltage.
Basically it's the maximum voltage you can read off the panel with a multimeter when there is no load (motor, lights, battery, etc) connected to it.

Vmc is being a bit harder to track down. I think it's the max voltage read from the panel while you have max current also running. I'm guessing a little bit one this one.

Badger

Â¡Niers! · Post by **Â¡Niers!** » Tue Mar 24, 2009 3:36 pm

Wasn't looking to find out what size panels I need. Got that already.
As I said in my first post, I'm basically just wanting to know if anyone can help me figure how long it will take to charge the batteries.
So, the amount of power I am drawing doesn't matter since I'm sure that will change. I just want a better idea of what I got to work with, so I can adjust my usage to what I have as a supply.
I live in Oregon, so I can't likely test run it right now since we never get sun out here and I wouldn't get anything close to Black Rock results.

Â¡Niers! · Post by **Â¡Niers!** » Tue Mar 24, 2009 3:40 pm

Thanks Badger!

capjbadger · Post by **capjbadger** » Tue Mar 24, 2009 4:04 pm

Time to charge:

http://wheelchairmotor.com/catalog/page30.pdf

http://www.csgnetwork.com/batterychgcalc.html

1000 mAH = 1 AH (amp hour)

Badger

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