Originally Posted By 360view

I have wondered
"how is the best way to test a battery to determine its health and expected remaining lifetime?"

There is a standard test to determine the "internal resistance" of a battery's guts.

You let a fully charged batery discharge two different currents through two known resistances then solve a equation for the unknown.

I have a 15 year old Snap On tester
that measures the voltage drop when a load of 130 amps is applied.
If i added extra resistance that would reduce the load to about 65 amps i could use the two tests to calculate the internal resistance by hand.

I have thought about buying this $160 tester:

https://www.amazon.com/Associated-Equipm...uct_top?ie=UTF8

It automates calculating the internal resistance
plus gives you other estimations.


I do this as part of my job.

Having a base line and knowing he design specifications is key to figuring out a batteries health and expected longevity.

Randomly testing a battery will tell pretty much nothing beyond is it bad right now.

Now if you were to test the battery new, then at every oil change you could log and track the data and come up with something useful.

They say there are no such thing as a stupid question.
They say there is always the exception that proves the rule.
Don't be the exception.