Since last summer, I have been using a 5kWh lithium battery with my rooftop solar, and the biggest change has been how little electricity I buy after sunset. I used to run the dishwasher, washing machine, and heat pump whenever convenient, then wince when the evening peak rates appeared. Now the battery charges from excess solar during the afternoon and carries the house through those expensive hours.

My installer set the system to keep a reserve for outages, while allowing discharge down to 20% on normal days. That setting has worked well for us. On sunny weekdays, the battery usually reaches full by about 2:30 p.m., and I start cooking around 6 without drawing from the grid. My utility bill dropped from roughly $180 a month to $105 over the first three months, despite running the air conditioner more than last year. Peak-hour reduction is obvious in the monitoring app.

I did have one stressful moment. After a firmware update, the battery stopped discharging overnight and showed a communication warning. I power-cycled the inverter, checked the cable connections, and waited ten minutes before restarting it. The warning cleared, and support confirmed the update had reset the operating mode. I did not open the battery cabinet or bypass any safety controls.

For anyone comparing a solar battery system, I would pay close attention to usable capacity, inverter compatibility, and the warranty rather than just the headline storage number. My setup includes a DIY electronics project nearby using a "4s lithium battery charger protection board module" for a 12V pack, but that is not connected to the home battery or mains wiring. Overall, the automatic peak shaving is what I appreciate most: less mental arithmetic, fewer expensive evening kilowatt-hours, and a calmer bill.