What is the difference between amps and amp hours?

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asked Apr 27, 2022 in Other-Home/Garden by telcomutties (4,050 points)
What is the difference between amps and amp hours?

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answered Apr 28, 2022 by Skeethansen (3,210 points)
The difference between amps and amp hours is that amps are a unit of electrical current and amp-hours are units of current storage capacity.

An ampere measures electricity.

Volts represent the difference in potential that drives amps to flow through the closed circuit.

Therefore, while amps represent the volume of water, volts carry the water through the circuit.

The meaning of Ah in battery terms is Amp Hours.

The A stands for Amps and the h stands for hours.

So for example if a battery says it has 100 Ah it means the battery has 100 Amp Hours.

An ampere hour or amp hour is a unit of electric charge, having dimensions of electric current multiplied by time, equal to the charge transferred by a steady current of one ampere flowing for one hour, or 3,600 coulombs.

The commonly seen milliampere hour is one-thousandth of an ampere hour.

As the name suggests this means how many amps the battery can deliver in an hour.

For example, a 12V lithium battery with a capacity of 100Ah can deliver 100A to a 12-volt device for one hour.

The same 100Ah battery could supply power for 4 hours (100/25=4) to a 25 ampere device.

One ampere-hour (or amp-hour or Ah) is a current of one ampere flowing for one hour.

The amount of charge transferred in that hour is 3,600 coulombs (ampere-seconds).

A milliampere-hour (mAh or milliamp-hour) is a thousandth of an amp-hour.

An amp-hour is one amp for one hour, or 10 amps for 1/10 of an hour and so forth. It is amps X hours.

If you have something that pulls 20 amps, and you use it for 20 minutes, then the amp-hours used would be 20 (amps) X . 333 (hours), or 6.67 AH.

The key is to use the watts you know to calculate the amps at the battery voltage .

For example, say you want to run a 250 watt 110VAC light bulb from an inverter for 5 hours.

Amp-hours (at 12 volts) = watt-hours / 12 volts = 1470 / 12 = 122.5 amp-hours.

What is the difference between amp-hours and watt hours?

Put simply, the power of an amp-hour (or, thus, mAh) depends on the voltage, whereas a watt-hour is always a watt-hour.

Other variables and terms, such as cycle life and C-rate, also affect the real-world available energy in a battery, but using watt-hours at least eliminates the ambiguity of the amp-hour.

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