What is Amp hour (Ah), milliAmp hour (mAh)?

What is Amp hour (Ah), milliAmp hour (mAh)?

A common term in the battery industry is Ah and mAh, below is described which term means.

What is the AmpHour (Ah) rating?

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 accepted AH rating time period for batteries used in solar electric and backup power systems (and for nearly all Cyclic AGM batteries) is the "20 hour rate". This means that it is discharged down to 10.5 volts over a 20 hour period while the total actual amp-hours it supplies is measured. Sometimes ratings at the 6 hour rate and 100 hour rate are also given for comparison and for different applications. The 6-hour rate is often used for industrial batteries, as that is a typical daily duty cycle. Sometimes the 100 hour rate is given just to make the battery look better than it really is, but it is also useful for figuring battery capacity for long-term backup amp-hour requirements.

What is a milliAmp Hour (mAh)?

MilliAmp hour means how much current a battery will discharge over a period of one hour. Higher numbers here reflect a long battery runtime and or higher storage capacity. Higher mAh ratings do not necessarily reflect on speed but more on runtime. For example a 2000 mAh pack will sustain a 2000 milli amp (2 amp) draw for one hour before dropping to a voltage level that is considered discharged. A 1700 will sustain a 1700 mAh (1.7 amp) draw for one hour. 1000 mAh is equal to a 1 Amp Hour (AH) rating.