Dave, I ran into a good deal and picked up 200 rechargeable 4.5 Amp Hour Universal Batteries, I wired up 30 parallel for each bank. They are in a cabinet that is cooled by 12V computer like fans that run on fractions of an amp of power. Each bank is connected to a Polar Power controller that senses dawn & dusk with settings for run times .30 min, to 24 hours. That gives me continuous power and the ability to automatically have things turn on. The controllers are fed by 55 Watt panels. I run 12V lights for the pond (20 lights) and have a power inverter that changes the 12V to 110DC for things like my aeration system, radio, & power tools. I'm also installing a water pump and sprinkler system for my food plots (deer!). I have regular electricity at my place, just couldn't justify the cost of running it 400 yards to my pond. So far I have about $700 tied up in everything, but there's no electric bill and I have more power than I need at this time. It's cool stuff.