How many batteries?
The short version
Multiply what you use in a day by how many days you want to go without sun. That's how much you need to store. Then divide by what each battery really gives you.
You need about 10.5 kWh stored.
| 3 | 48V server-rack batteriesHomes, cabins, tiny houses, most buses · about 4.6 kWh usable each · EG4 LifePower4 |
| 9 | 12V 100Ah lithium batteriesVans and small rigs · about 1.2 kWh usable each · Battle Born 100Ah |
| 6 | ~2 kWh power stations (or add-on packs)Outages and camping · about 1.8 kWh usable each · Power stations |
Go deeper: how this works
- Find your daily use: the highest month on your power bill ÷ 30. Or add up your appliances.
- One day of storage covers a night plus a grey morning. Most people pick 1–2 days; panels refill the rest.
- "Usable" is what you can actually draw: LiFePO4 lets you use about 90%.
Get the whole setup
Batteries are one piece. The guides size panels and the inverter for your darkest month too.