Plain-English help with battery spec sheets
What the numbers on a battery label mean
Battery spec sheets pack in kW, kWh, percentages and warranty terms. These notes explain each one in everyday words, show how they connect, and help you compare one sheet with another.
All the spec notes
- kW versus kWh: power and energy on a battery spec sheet
Why a battery label shows both kW and kWh, what each one measures, and how to read the two numbers together without mixing them up.
- Usable versus total capacity on a battery label
Why usable capacity sits below the headline number on a battery label, what causes the gap, and which figure to use when you plan.
- Depth of discharge explained
What depth of discharge means on a battery spec sheet, the two ways it's defined, and how it links to usable capacity and cycle life.
- Round-trip efficiency: what is lost between charging and using
What a round-trip efficiency percentage on a battery spec sheet means, where the missing energy goes, and how to apply the figure to your own numbers.
- Continuous power rating: what the kW figure limits
What a continuous output rating limits on a home battery, how it differs from peak power and from capacity, and how to check it against your loads.
- Volts, amp-hours and watt-hours: converting between them
How to turn a battery's voltage and amp-hour label into watt-hours, so you can compare two batteries on the same scale, and where the sum falls short.
- Reading a battery warranty: years, cycles and throughput
What battery warranty terms such as years, cycles, throughput and end-of-warranty capacity say, and what to look for in the maker's own warranty document.