How come some use Watt-Hours and some use Ampere-Hours?
In: Technology
When you are comparing batteries of equal voltage, using Ah or Wh are basically the same because you can just multiply by voltage. For example standard car batteries are 12V and their capacity is quoted in Ah. Why not Wh, which would work equally well? The things that a car battery powers (starter motor for example) pull a known current so it makes sense to quote capacity in current x time.
This applies to phone batteries that all work at the same voltage.
In contrast electric cars have batteries of a range of voltages. Roughly speaking higher voltage is more efficient and more compact but requires more expensive components. Hence designers pick different values depending on their needs. Given you care about the total energy stored in the battery, and you don’t necessarily know the voltage, it makes sense to quote the capacity in Wh.
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