Battery charger and battery as secondary power source


New Member
Oct 5, 2021
I'm off grid with a water storage system. I have a 12 volt water pump in the house near my water storage tanks. Seeing as the pump is so far from my solar array and batteries I've set up a single battery next to the pump with a 1.5 Amp battery maintainer. This has worked well for years now. The charger keeps up with my water use and I've never had to even replace the battery and even when my solar system is low on power I've got juice to run my water pump. The idea is the battery can charge off my solar power system durring the day when power is abundant and when the pump runs it drains a dedicated separate battery instead of my battery bank.
I've recently added a refrigerator (100 watts) whenever the compressor kicks on it dims or flashes the lights. If the TV is on it shuts it off. I'm not sure if a larger inverter would help or not but I'm thinking the set up I have for the water pump has worked so well why not do the same for the fridge. The initial start of the compressor is a large drain on my solar battery bank. Any thoughts would be appreciated. I'd use a 4 - 7 Amp maintainer instead of the 1.5 Amp maintainer I've been using and try it on the same water pump battery. If it wasn't sufficient perhaps I'd try using a separate battery and maintainer. Ofcourse I'd ad a power inverter as the fridge is 120v ac. Same idea as the water pump. Could charge a separate dedicated battery durring the day and the fridge would not drain my battery bank at night and the start up wouldn't be a heavy draw on the solar bank. Just the single battery.