DoD (Depth of Discharge)

Written and checked by the Energy Merchants desk · Reviewed 3 October 2026

DoD stands for depth of discharge. It is the percentage of a battery’s capacity that has been drawn out. Discharge a battery from full to half and you have used 50% DoD.

Cells wear faster when they are regularly emptied hard, so manufacturers set a recommended or maximum DoD. Lithium iron phosphate batteries commonly allow a high figure, often 90% or more, while older chemistries allowed far less. The exact limit is on the product datasheet.

Why it matters for sizing and STCs

DoD is the reason nominal and usable capacity differ. Take a battery with 10.0 kWh nominal capacity and a 95% allowed DoD. The usable figure is about 9.5 kWh. That usable number is what the Cheaper Home Batteries Program counts, as covered under usable capacity.

At the time of writing the 2026 factor is 6.8, so 9.5 kWh gives 9.5 x 6.8 = 64.6, which is 64 STCs after rounding down. Using the nominal 10 kWh would have produced 68, which is the sort of mismatch a reviewer catches.

In practice

You rarely type DoD into a claim. The approved product listing already reflects it in the usable figure. Where DoD helps is the customer conversation: a lower usable fraction on a cheap unit can mean less real storage than the headline suggests, so compare usable kWh, not box size.

Warranty terms also lean on DoD. Some warranties guarantee a number of cycles or throughput at a stated DoD, and running the battery harder can affect them.

Common confusion

DoD and SOC are two views of one reading. SOC counts what is left. DoD counts what has gone. A battery at 80% SOC is at 20% DoD.

DoD is also not efficiency. Round-trip efficiency measures energy lost between charging and discharging. See round-trip efficiency.

See battery STCs for the claim steps, and browse the glossary for related terms.