Battery Capacity milliamp hour mAh Amp hour Ah

A battery can provide a certain amount of total current over time. That current, times it’s voltage, is the power that it can provide.

  • 1Ah = One ampere/amp hour.
  • 1mAh = One milliamp hour.
Electronic power math examples with batteries and an LED circuit learning electronics lesson
Electronic power math examples with batteries and an LED circuit learning electronics lesson

A single cell (battery) that can provide 2 amps of current for one hour before the battery is discharged, is a 2Ah battery.

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Most batteries are not meant to be charged/discharged in one hour (or less). More often they provide a lower current for a longer period of time. Somewhere closer to 1/10th of the current for 10 times as long. 

Smaller batteries tend to have their ratings specified in milliamp hours (mAh).

  • One mAh is 1/1000th of an Amp hour,
  • One Ah is 1000 milliamp hours.

Parallel connection for more current:

If a 1.5V 2Ah cell/battery has enough voltage to power a load, but the battery will die too quickly, then you can connect cells/batteries in parallel. Parallel cells/batteries have each of their negative terminals electrically connected to each other, through metal on metal contact, while also having all of the positive terminals are electrically connected. They form a single two terminal battery that share the power demands.

Never let any parallel cells make a direct connection between their positive and negative terminal. That is a short circuit! Cells/batteries must be at the same voltage at the time they are connected in parallel.

Three parallel 2Ah cells will be able to provide a total of 6Ah of current.

Series parallel batteries basics visual diagram by electronzap
Series parallel batteries basics visual diagram by electronzap

If you need more voltage from parallel batteries, then you can connected them in series as long as each series connection has the same total capacity (Ah/mAh). 

Series batteries for more voltage:

Connecting the positive terminal of one battery to the negative of a another battery, is connecting them in series.  Just make sure that far ends of series batteries never come into contact. Doing so would create a short circuit.

Series batteries add up their voltage. 

The circuit current has to flow through each of the series batteries. Therefore they all discharge based on the current provided to the circuit.  Three 1Ah batteries connected in series, providing 1A of current to a circuit, will all discharge in 1 hour.

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  • Information on this site is not guaranteed to be accurate. Always consult the manufacturer info/datasheet of parts you use. Research the proper safety precautions for everything you do.
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