Wirebook › Glossary › Milliamp-hour (mAh)
What does mAh mean on a battery?
In one sentence: The battery-size number printed on phones and power banks; it counts charge, not energy, so it only compares fairly between batteries at the same voltage.
A little more
mAh (milliamp-hours) counts how much electric charge a battery can push out: 1,000 mAh could supply one amp for an hour. It's the big number on most phone and power bank boxes.
Charge isn't the same as energy, though. Energy also depends on the voltage, so a 10,000 mAh power bank counted at 3.7 V and a 4,500 mAh phone at 3.85 V can't be compared just by dividing. Converting both to watt-hours fixes that, and real charging also loses some energy as heat, which is why a 10,000 mAh bank gives a typical phone about 1.4 charges, not 2.
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