Odd battery test

[Donald]

I have an Ancel battery tester. Tested my new deep cycle battery that is labeled 800 MCA. Plugged 800 MCA into the tester and it said the battery had 1025 CCA. That's odd that the CCA as tested is more than the MCA.

Multiplied 800 MCA x .77 to get 616 CCA rating.

Tested a second time, plugged 615 CCA into the tester and it said the battery had 825 CCA.

Maybe the Ancel does not convert MCA properly?

 

[WobblyElvis]

Maybe the battery has to be cold to measure CCA

 

[SC Maintenance]

Did you just take it off the charger? My tester gives strange ratings until its been sitting a while , voltage too high.

 

[mk378]

Multiplied 800 MCA x .77 to get 616 CCA rating.

That's not the definition of MCA. MCA is cranking amps measured using the same testing protocol as CCA but with battery temperature 32 F instead of 0 F.

Testing actual CCA is complicated and really never done in the field. Internal resistance test results are at best an evaluation of good / marginal / no good and not specific numbers.

 

[Donald]

That's not the definition of MCA. MCA is cranking amps measured using the same testing protocol as CCA but with battery temperature 32 F instead of 0 F.

Testing actual CCA is complicated and really never done in the field. Internal resistance test results are at best an evaluation of good / marginal / no good and not specific numbers.

On the internet it says to multiply MCA by .77 to get CCA. Is that not a valid conversion factor?

 

[Donald]

So as someone in an Amazon review posted the MCA is not programmed properly.

I key in 800 MCA and run the test and it comes back on the display as the battery is good with a capacity of 1000 CCA. That just cannot be.

 

[mfewtrail]

Conductance testers will almost always test over the rating on the label rating on a new battery, but yours does seem optimistic on that particular battery and programming is likely to blame. I've had a tester before that optimistically rated AGM batteries in particular due to what I assume is a programming error(it's pretty much spot on when it comes to regular FLA batteries when compared to other testers).

I know your tool isn't this brand, but this rating is pretty accurate even with the cheapest of conductance testers in my experience: "On average, a new battery's CCA as measured by a Midtronics tester will read 10-15% higher than its stated rating"