How Do The Battery CCA Testers Work ?

[KTMsm]

I trade in cars / bikes and I have lots of projects so I bought a cheap battery CCA tester which so far seems to be accurate in telling me if a battery is dying

However I have a 120cca battery which my tester said was 222cca so I grabbed another tester which showed it as 65cca

So what's gone wrong ?

I know they aren't perfect but it has always given a good indication in the past so I presume something must be fooling the one tester hence I wondered how they work ?

[KTMsm]

Yes you enter the CCA and it takes approx 5 seconds

It's a gel battery, it could be the first gel one I've tested.

Unlike the older type load testers these are just small mobile phone sized £25 devices

I suspect the yellow one is correct as the bike doesn't start after a couple of days.

Maybe it copes with gel whilst the black one (which generally seems to be a better tester) doesn't

Edited by KTMsm on Tuesday 31st August 11:24