What is the easiest way for me to measure the amount of "juice" that's left in an alkaline battery?

Question

This question applies equally to both non-rechargeable batteries and rechargeable batteries.

I want to know if I managed to fully recharge my rechargeable batteries (mine are primitive), and how much battery life is remaining in my non-rechargeable ones.

Here is how to do it for LiPo's http://electronics.stackexchange.com/questions/2601/how-can-i-tell-how-much-juice-a-lipo-battery-still-has-in-it — Kellenjb, Jan 24 '12 at 19:04
@inquilineKea, can you specify a chemistry, this is a very chemistry dependent process. — Kortuk, Jan 24 '12 at 19:08
@Kortuk - The OP seems to want to do this for all chemistries, which will be very difficult. — Kevin Vermeer, Jan 24 '12 at 19:09
@KevinVermeer, I am specifying that it seems to be too broad to reasonably answer. Asking if the user can specify a chemistry to receive answers for. — Kortuk, Jan 24 '12 at 19:14

Al Kepp · Accepted Answer · 2012-01-25T10:31:45.490

If we talk about small AA, AAA and coin batteries (both 1.5V and lithium 3V), then the simplest estimation can be made using a voltmeter. The voltage goes down (declines) over time and usage.

Note that each particular device needs a different minimum voltage to operate normally, so for example a battery from one device which seems dead can be put somewhere else and operate normally (at least for a little while). For example my digital weigh is quite demanding - it ceases operation already when the voltage drops to 2.88 V, and those lithium batteries are still well usable in bicycle computer or somewhere else.

Update: Note that alkaline batteries have got some kind of self-healing effect. When they are not used for a while, their voltage goes a bit higher. This can mislead your voltage measurements. So you should put them back to some load for a few seconds and then you can see their real health. Also note that totally dead batteries don't need this; they show voltage near to zero even without any load.

There is some value to measuring under load. I have very little experience with alkaline batteries. This does not work for lithium batteries though, they need to have a load applied otherwise their discharge curve is almost flat minus the very last bit of death. — Kortuk, Jan 24 '12 at 19:41

What is the easiest way for me to measure the amount of "juice" that's left in an alkaline battery?

1 Answers1

Linked