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Battery Round-Trip Efficiency Loss Calculator
Estimate the usable energy a home battery delivers and the energy lost over a full charge and discharge cycle from its stored capacity and round-trip efficiency.
Screening result
Fine Print and Sources
Screening estimate only. These tools use only the values you enter and simple planning math. A licensed electrician or battery installer is authoritative for final capacity, backup panel design, and installation. Confirm the numbers with a professional and get written quotes.
Round-trip efficiency is the share of stored energy a battery returns over a full charge and discharge cycle. This tool uses the manufacturer round-trip efficiency you enter, so the result is only as accurate as that figure. Real losses change with temperature, charge and discharge rate, depth of discharge, and inverter efficiency, so treat this as a screening estimate.
- US Department of Energy, battery backup for your home: explains that home battery sizing depends on the loads you want to back up and how long you want to run them.