How Many Batteries Does a House Need?

In depth

Example: a home running a 1.5kW AC, a 0.2kW fridge and 0.2kW of lighting for six night hours needs about 11.4kWh. With lithium at 90% DoD that is roughly 12.7kWh nameplate, so a 15kWh bank in practice.

The same calculation with gel roughly doubles the number because allowed discharge is 50%, i.e. around 23kWh nameplate.

Then translate energy into units: a 15kWh bank can be one 51.2V 300Ah lithium module, or several 12V 200Ah gel batteries in series and parallel.

Related products with specs and prices

Common mistakes to avoid

• Comparing amp-hours only and ignoring voltage, ending up with four times less energy than needed
• Discharging lead acid below 50%, which cuts life to less than half
• Picking a bank that does not match the inverter voltage, so charging fails or runs inefficiently
• Thin cable or a long run between bank and inverter, causing voltage drop and lost power
• Mixing new and old packs, or different capacities, on the same bus

Next step

Send your load list and required hours over WhatsApp, or use the on-site system calculator to size the battery bank and array.

Technical advice is free, and the recommendation is based on your real consumption, inverter voltage and installation location rather than on the largest battery in stock.

Frequently asked questions