A home battery moves electricity between times. It can store midday solar for evening use, shift grid imports, support selected loads during outages when designed for backup, or respond to electricity tariffs and grid programs.
It cannot create energy, remove seasonal solar variation, or guarantee savings.
Define the battery's job
Start with a measurable goal: increase solar self-consumption, avoid expensive tariff periods, provide outage resilience, manage an export limit, or participate in a grid program. Different goals produce different sizes, controls, and operating priorities.
Compare capacity and power
Usable capacity in kWh describes stored energy. Power in kW describes how quickly the battery can charge or supply loads. A large battery with limited output may not run several high-power appliances together.
Use interval consumption and solar data rather than a daily total alone.
Account for losses and aging
Charging and discharging lose energy. Capacity declines with calendar time and cycling. Compare round-trip efficiency, warranted years, cycles, throughput, retained capacity, operating conditions, and claim procedures.
Verify backup design
Many grid-connected batteries stop during an outage unless approved isolation and backup equipment are included. Confirm supported circuits, output, transition, reserve, solar operation during the outage, and restart procedure.
Model local tariffs and programs
Battery value depends heavily on import prices, export payments, time windows, incentives, and network rules. Read the relevant market guide after learning the global concepts here.
Continue into solar equipment for inverter architecture and solar costs for return modelling.
