Why are larger (house, car) rechargeable batteries specified in (k)Wh but smaller batteries (laptop, smartphone) are specified in (m)Ah?

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I get that, for a house/solar battery, it sort of makes sense as your typical energy usage would be measured in kWh on your bills. For the smaller devices, though, the chargers are usually rated in watts (especially if it’s USB-C), so why are the batteries specified in amp hours by the manufacturers?

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Anonymous 0 Comments

> rated in watts (especially if it’s USB-C), so why are the batteries specified in amp hours

Those are different units completely.

Watts is a unit for POWER, Amp Hour (or watt hour) is a unit of CAPACITY. See the difference as how much water a hose can deliver vs how much water a bucket can hold.

The main ‘feature’ of a battery is how much capacity they can hold so while it is relevant to know what kind of power it can deliver its still more important to know how much capacity fits in there.

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