Since I finished my coop last summer, I have been looking for a lighting system that was low cost, 12 volt, and included a timer for winter egg production. Originally I wanted to use solar but decided it was too expensive. I finally got something together that seems to work well. Here are the details for anyone that's interested. I can post pictures if you want. I modified a programmable thermostat to work as a timer as shown here: http://www.reuk.co.uk/Use-Thermostat-as-12-Volt-Timer.htm. I ordered a 200ma LED fixture from http://www.backwoodssolar.com/ (model number L-MINI LUX Warm Yellow). I wired in a wall switch to turn the light on when the timer is off and hooked to a 12v battery which I can unhook and take to the garage to recharge as needed. I don't know how long the battery will last, but so far it has run for almost a week and the weather has been cold. My total cost for the system was about $40 because the thermostat was given to me and the battery is from my motorcycle which doesn't get used in winter anyway. You could probably buy all the parts and do it for $100 - $120.