Took it for a long drive (40 min of highway) and went back to get it tested but their tester wouldn't work.

Voltage was 12.54 when reading directly from the battery.

I just plugged in my solar tender in the trunk outlet for now and will see what it reads tomorrow.


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The battery tester would have picked up a bad cell/short fwiw

:iagree: Percent of charge is usually derived from specific gravity and is not a substitute for a load test or even a good way to evaluate how good a battery is.

Not in my case at all. My battery tested full charge and 550 CCA. It could also start my car a few times at 0°F but it wouldn't start after a few minutes of a small load like the radio. It's quite a mystery

If battery tested good and only a year old and you are not having typical battery issues, it is likely good and just needs to be charged with low amps setting for 24 hours. If you are concerned charge it up and then have it load tested.

When in doubt of electrical testers, could also do the old skool hydrometer test

The hydrometer will only tell you state of charge and/or pick out a bad cell. There is no better way than to put the battery on an old school load tester or AVR (I think someone posted a picture of a Sun unit in another thread) and crank the full rated load out of it. The newer computerized testers only put on a partial load and then try to extrapolate from there, they are often wrong from what I have seen. Once you have taken 500 or 600 amps out of the battery and watched the voltage hang on while smoke starts coming out of the tester you can be pretty confident you are good to go.

And yet my battery tested full load now the machine maybe pulled 350a and extrapolated 550 CCA because it was 70-75°F at the time. No drop in voltage yet as I said once you pulled 50 mAH out of the battery it couldn't turn over the engine. it was as if it was a 550A battery with only 0.5AH vs 90AH capacity. I've never seen anything like it.

I was going to do an actual measured capacity to pull say 5A and see how long it would run before the voltage tanked but then I ended up just taking it in for the $10 core exchange.

Old school lead acid batteries can have issues with buildup on the plates that can be shocked off but I don't remember the process. If a battery holds a charge but no capacity like mine it's probably a good candidate for the shock treatment.

Yes, there are always exceptions, hopefully you had battery out of the vehicle when testing. AFAIK the shock treatment was to discharge it slowly and completely (maybe light bulb) and then put about 20 to 40 amp charge into it. Just buying some time though, more of a car dealer/flipper thing.