Solar Battery Backup Calculator
Frequently asked
How do I calculate battery backup for solar?
Multiply backup load in watts by backup hours to get energy required, then divide by battery voltage, depth of discharge and inverter efficiency. This calculator rounds up to the next standard battery size.
What is depth of discharge for batteries?
Depth of discharge (DoD) is how much of the battery capacity can be safely used. Lead-acid batteries are usually 50%, lithium-ion 80-100%. This calculator lets you set DoD.
How many batteries do I need for 1000W for 4 hours?
For 1000W for 4 hours on a 12V system with 50% DoD and 90% efficiency, you need about 740Ah total, which is about 4 x 200Ah batteries. The calculator computes this exactly.
Which related calculators pair well with the Battery Backup Calculator?
People planning battery backup often also need Solar Rooftop Sizing Calculator and Solar Savings Calculator. Each is free and quotation-ready.