Solar panel to run lightbulb

[gale65]

Are you adding heat for the waterer or just to heat your coop?

 

[Bear Foot Farm]

I would like to be able to run a 100 watt lightbulb. How big would a solar panel have to be to run one?
How much would it cost?
know anywhere I could get one?

https://www.backyardchickens.com/forum/viewtopic.php?id=554615

Posted by Cobrien:

Hello,
I am a solar energy engineer and I don't believe this is practical IF you are talking about using solar ELECTRICITY as opposed to heating air, water or some other substance with the sun's heat directly.

Here's some math that explains why I think the solar electric approach isn't practical:

Say you want even a meager 100W heater for 8 hours overnight. You would need 8*100 = 800 Wh of energy.

Say you get 3 sun hours per day in the winter- this is location and climate dependent. (I got this number from here: http://rredc.nrel.gov/solar/pubs/redbook/). Say you have a meager 200W solar panel, this would be about 3'x5' and cost about $800-$1000.

This would give 600Wh (200W * 3 sun hours) of energy and you'd lose maybe 20% of this by storing the energy in a battery during the day when the sun shines, and then taking it out of a battery at night. This leaves 480 Wh of energy - not enough for your meager 800Wh that you need to power a 100W heater for 8 hours. You'd need 2x as much solar capacity at least.

That's maybe $1600 to $2000 just for the solar panels alone.

I don't have expertise with batteries and charge controllers so don't know how much they'd cost, but I'd budget maybe $500 for those as a guess. And this is only for a 100W heater which is barely enough for a small coop.

Disclaimer - the 20% battery loss could be overly optimistic so if anyone plans on doing this you should check this with a battery expert - I know a little about them but it is not my expertise.​

 

[MadChickensVT]

Those prices are out of date. Panels are under $2/watt now.

You don't need heat in PA

 

[Bear Foot Farm]

Yesterday 11:41 pmThose prices are out of date. Panels are under $2/watt now.

Maybe the very cheapest

http://www.google.com/products/cata...=X&ei=1kSoTtGjMIq40QGcooWNDg&ved=0CHYQ8wIwAQ#

Evergreen 200 Watt Solar Panel ES-A-200-FA3
$636 online

Even if you could get them for $2/Watt, by the time you figure in batteries and inverters, it's FAR cheaper to run grid power to the coop if you feel you need heat​

 

[MadChickensVT]

Check out these prices http://www.sunelec.com/

$1.34/watt for UL listed panels made in Germany

Evergreen, Kyocera, etc for not much more.

And yes, solar electric is not a good way to get heat. Much better to just collect the sun's heat directly.

 

[EKC Farms in the desert]

I plan on building a coop with in the next 6 months (hopefully) waiting to close on our house. My thoughts and plans are to run 2 small fans, a regular light bulb, and a heat lamp off of a solar panel. I REALLY want to run the coop with solar. I have been doing a lot of research but I am not finding much info that helps out a person with no electric skills what so ever. Thanks for posting this question and all the information you have received. I have learned a good bit. I posted the same question about a month ago, and was also given good solid information on solar panels. Good Luck.

 

[simplynewt]

Thanks for the thread. Contemplating adding a light to the cop using solar energy and this thread has been very informative. Thanks for the lonks. More appreciated.

 

[Mavrik]

It would be far cheaper just to run power out to the coop and will last forever, with no maintenance, unlike solar, panels and batteries degrade and batteries don't like cold weather, loose capacity (or real hot). Running a power line is as easy as running sprinkler lines and one would not be limited on what you can run. Cost lest than a 50 cents a foot, underground, PVC conduit and wire, DIY. A coop a 100 feet from a power source, ready to use, would easily cost under $100, DIY. I think the bear minimum to run in a coop is a light and heater for the water. While you have a trench open, run water out there too.

 

[TDM]

I use solar to provide supplemental lighting for my hens. It isn't practical to run a power line to a moveable hen house out on pasture. Furthermore, our utility company charges a $25 per month service fee for any power delivered. So, that is $300 per year just to be hooked up. That does not even include the $ per kilowatt hours. A $300 per year service fee provides a lot of incentive to go off grid.