I installed my solar battery last spring because our evening electricity use was expensive. We already had rooftop solar, but the panels stopped helping once the sun went down, just when cooking, laundry, and the heat-pump water heater were busiest.

My system uses a 10kWh lithium iron phosphate (LiFePO4) battery with a hybrid inverter. I had seen small batteries advertised as “lifepo4 12v 12ah,” but that capacity would not suit our house. The installer mounted the battery in the garage, connected it to the inverter, and set it to charge from solar and discharge during our utility’s peak pricing period.

The biggest surprise was how visible the savings became in the monitoring app. On sunny days, the battery reached full charge by early afternoon. Around 4 p.m., it started powering the house, and grid consumption dropped almost to zero. Our evening peak usage fell by about 8–10kWh, and my monthly bill has been roughly $45–$65 lower than before, depending on the weather. That is not a dramatic windfall, but it is steady, especially in summer when the air conditioner runs after sunset.

I did have one minor troubleshooting moment. During a cloudy week, the app showed the battery at 0% even after sunshine returned. I checked the breakers and found the battery isolator had tripped. After switching it off, waiting, and turning it back on, the system restarted normally. The installer said it was probably a protective trip, not a battery failure. It has behaved reliably since then.

I now check the state of charge before running the washing machine and schedule heavier loads while solar production is available. The battery also keeps our refrigerator, internet, lights, and garage door running through short outages. It has not paid for itself yet, but the lower bill and reduced grid dependence make it worthwhile.