Multiple batteries, what if one dies

[Smoove]

So lets say I have 3 batteries in back and 1 in front. Other than demo's or something causing some serious voltage drop, how would I know a battery died and which one it is?

[Noel989]

Lower voltage than the usual

And then check each one

Just what I think

[n8ball2013]

your resting voltage will be lower and you will drop faster.

[AMI CUSTOMS]

If one is bad or dead, you would see lower voltage all the time, that dead battery will pull down the other batteries trying to charge itself until the point it is completely dead then you would only notice a different when the system is on and up to normal demo volume. To check you would need to have each battery load tested with a battery load tester or do it yourself. To do it yourself just disconnect each battery, charge up to 13.1 or greater, then put some kind of load on it, light, anything, remove the load and see if voltage recovers. if is doesn't go back up then battery no good, generally speaking you would need to apply a pretty big load to it to get some good dip, like 1 volt or more and then you can see if it will recover. Normally what I do is replace my starting battery with said bad battery in question, the starter will put a nice load on it lol.

[Smoove]

Thanks for the info. learn something new here all the time

[tacomaguy1]

Can have a battery shop load test them also....they did my 3100's for me when I thought one was bad