If you have an electric meter, it shows energy consumed in Watts per hour. This energy has an amount, Joules that is. But in a battery there is energy stored that also has an amount. So it should be in Joules as well. But the unit is different: Ah,(or mAh).Why is that and what is the difference between these two u
In: Physics
The amount of energy a battery stores is measured in watt hours or joules, It’s what you get when you integrate current(amps) with voltage.
The reason Ah or mAh is often used is because it’s a more useful measurement for devices that don’t include a boost converter. If you have a linear regulator, the current drawn doesn’t change with battery voltage, the extra power from having a higher voltage is wasted as heat.
With some loads, it’s even worse than that, as the current drawn can be higher at higher voltages. A dumb flashlight, for example.
Basically, it’s a measure of charge(like coulombs), rather than energy(like joules)
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