# Can I connect my digital ammeter in parallel to a battery to check the maximum current It can supply?

Can I connect my digital ammeter in parallel to a battery to check the maximum current It can supply? Will it burn my ammeter or its fine? I have tried it and nothing happened so is the ammeter being damaged slowly from inside?

• What do you mean? Can you draw a circuit? The only circuit that I can imagine that just contains a battery & a meter has them in series, in a loop. Aug 16, 2020 at 13:38
• Yes I mean that. Aug 16, 2020 at 13:55

It'll most probably burn your ammeter (or at least blow the fuse, if the ammeter has one) unless your battery is tiny. And it might damage the battery as well.

E.g. car batteries even burn screwdrivers when used as short circuit, so your delicate digital ammeter definitely won't survive.

But in theory, your approach is correct, you "just" have to make sure the battery's expected short-circuit current is below the rated maximum of the ammeter. If e.g. the ammeter has a 2amps range, then even any decent AAA battery will exceed that.

The already given answer is sufficient. However i just wanted to point out that in order to measure maximum current possible you needn't do this. Connect it with any resistance whose value is known precisely well and then measure the current. You'll be able to find out the internal resistance of the battery. The voltage of the battery divided by the internal resistance would simply give the maximum possible current.

• Your answer suggests that the classic model of a battery as an ideal voltage source in series with a resistor would be valid for whatever kind of battery the OP is asking about and, that it would be valid in the extreme case where the battery is "short circuited." I know that that model is a good approximation in many cases, but do you actually know that it works well for any battery type, and even in the case of a short circuit? Or, do you merely assume that what works in most cases must work for all? Aug 16, 2020 at 16:14