Slightly OT: Car battery Load Tester

I got one like this:

Thanks Fred

As I understand it, these do not load the battery excessively to test it, what they do is draw a small current, assume that the batteries internal resistance is constant with much higher currents, and then

Some people do not regard that as as valid a test as sticking a real heavy load on. But I reckon they work for most purposes.

Our local place uses something like this:

I have a ‘modern’ one. I’m not entirely convinced they are that accurate.

I tried it on an old battery, which I expected was on its way out, and sure enough the results confirmed my thoughts.

However, the new battery ( a quality one, which I charged) while it measured as good, the readings weren’t that accurate ( CCA that is).

I think I paid about £25 for mine, around 7 / 8 years back.

I’ve not used it since.

When I suspected the motor home battery recently, I just changed it. You can’t bump start a 3.8+ T diesel.

put it in gear & crank, the 3.8t will keep it rolling over the compression points.