Help with a solar project.

[Not_A_Llama]

From the cold-hearted perspective of an energy commodities guy... this is costing you about $0.15/day. If energy use were the same year-round as it was in your last 24 hours, you'll be spending $55 a year on electricity.

I like my projects ("investments") to return 10% or better, to match stock market performance. That means an initial cash investment of not more than $550, if it completely took your fridge offline, and the system cost nothing to run per year.

Another thought - do you actually need a battery? On an industrial scale, cold storage is considered one of the few *real* ways to store energy, in the sense that you can run the compressor balls-out during times of peak generation (lowest cost, in my world), and the "excess cold" carries forward to the times when the compressor isn't running. I don't know about the cooling ranges achievable with home systems, or the quality of insulation, but you might be able to tweak your thermostat to make the whole rig battery-free.