Electronic – How much current can you pull safely off a standard AAA battery

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This might be a stupid question. But how much current can you safely draw from a AAA battery.

I am currently powering my project from a worktop power supply and it draws at 5V 0.45A during normal operations and peaks to 0.7A. Now I need to make it portable and looking for the right battery. I need to keep my project as compact and light weight as possible. I was thinking of using four AAA batteries or suitable Li-ions to power it on the go. The max duration I expect is 1hr but I will be satisfied with 45 mins.

If you have any other suggestion of powering the project please help me out.

Best Answer

The maximum current depends very much on the chemistry of the battery.

The capacity of the three main (no Lithium) batteries is approximately:

  • Zinc-Carbon: 540mAh
  • Alkaline: ~1000mAh
  • NiMH: ~900mAh

The current limit and capacity of any specific battery can be found in its datasheet. For instance, the Duracell MN2400 has the following nice graph:

enter image description here

So you can see from that, 500mA would start to drop off significantly in voltage after around 1 hours. 1A would last about 30 minutes, if that. So 700mA would be somewhere between there.

Also, from the datasheet, you can find the impedance. 250mΩ in this case. At 1.5V full charge you should be able to draw up to (I=V/R) around 6A from it. It'll probably not like it, and get rather warm, or explode, but 500mA - 1A should be no problem.

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