[ELI5] Why are battery capacities expressed in Ah (Amperes-hour) and what does it mean, for example, a AA battery that is 2500 mAh?

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[ELI5] Why are battery capacities expressed in Ah (Amperes-hour) and what does it mean, for example, a AA battery that is 2500 mAh?

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Anonymous 0 Comments

That’s the amount of charge it has. Charge is measured in Coulombs, and an amp is a Coulomb/s. It’s like how we measure energy in kWh, Watts are a measure of power which is Joules/s. The h is a multiplication by hours, so the time factor cancels out.

A 2500mAh battery can supply 2500mA for one hour, or 25 mA for 100 hours or any other combination within reason. (Extreme circumstances may give different results)

You can also figure out how much energy it has from that. A double A battery is 1.5V, with 2500mAh, that’s .375 Wh of energy (1350J)

Anonymous 0 Comments

It’s ez. Just put “for an” in the middle.

1 Ah is 1 Amp for an hour.

2500 mAh is 2500 mA for an hour, which is 2.5 Amps for 1 hr.

So your AA battery will drive 2.5 amps for 1 hour.

Considering Watts which are volts x amps, and a AA is 1.5 volts: 1.5v x 2.5A = 3.75w
That’s a 3.75w bulb for 1 hour.

Anonymous 0 Comments

Like you’re five?
The mAh is how much energy the battery can hold. Like how much water can fit in a water bottle. More amp hours means the battery lasts longer. Or it can pour out more water (electricity).

Building on the water bottle analogy, the voltage is how much pressure the energy / water sprays out of the bottle / battery with. Higher voltage = higher pressure.

Anonymous 0 Comments

It’s the amount of charge the battery contains. An ampere is a measure of current – the charge flowing through a wire in a unit of time. So multiplying amperes by hours gives current per unit time multiplied by time, which is just current. They could give the battery’s capacity in coulombs, which is the unit for charge, instead. But they tend not to.

Anonymous 0 Comments

Amphours is NOT the capacity. That’s watthours. With amphours the voltage is missing. It’s like describing the capacity of a bottle by mentioning its area only, but not its height. Capacity is the volume of a bottle, not its area.

Anonymous 0 Comments

Energy is electrons flowing through your devices. The amount of electrons flowing is shown in Amps.

You can think of electricity in a wire like water flowing in a hose. Amps is the water itself flowing through. Not many amps, you’re only getting a trickle, a lot of amps and you’re getting ready for a fun summer water fight.

Now add pressure (voltage) and you’ve got power. If a ton of water is rushing though your hose you’re going to have a whole lot more force than if you just let a little out at a time. For electronics, that power is expressed as Amps per hour (Ah).

So with a battery you’re not connected a “spicket” but instead a “jug” that you put in a bunch of electrons to use for later. But when you’re figuring out how useful the jug is, you don’t care how many electrons are in there, you care how long you can keep your flow going because it’s that flow that makes your phone or whatever work.

A battery rated for 10,000 mAh holds enough electrons to keep trickling out one milliamp for 10,000 hours. So if you have something that needs 1,000 mA to run, you will have enough to power it for 10 hours.