tester read different on battery

[CarLuver]

My kid texted me her car would not start at work. its a 2019 hyundai . i went and jumped it . before i jumped it i checked the voltage and it was around 5.5 volts . put my battery pack jumper and it started right up . charge was 14.5 volts so most likely battery .

good thing there was a Costco not to far from her work and i bought a H6 battery . went back and installed it and all is good. I took the battery home .

i put it on a 10 amp auto charger and it charged up to 13.25 volts . the SOC was 98% while he SOH was 34%. 350 amp from listed 600 amp battery . this was from my chinese battery tester. So its bad according to the test. i also have a 100 amp toaster tester. tested it for the 10 seconds and the voltage did not drop much and it stayed at the 600 amp line. tried it a couple of times with the same result

this is making me curious on which is correct . one test says it bad and the other says its good . i don't intend to put it back though. almost 5 years on a battery is ok

 

[Lubener]

Use that five year old battery to get your core money back. A five year old battery which is questionable isn't worth keeping.

 

[SubLGT]

.... i also have a 100 amp toaster tester. tested it for the 10 seconds and the voltage did not drop much and it stayed at the 600 amp line. tried it a couple of times with the same result....

100A is a easy test to pass. Apply a load at 1/2 of the CCA rating for 15 sec and monitor voltage. At a battery temperature of 70F the voltage under load should be at least 9.6V after 15 sec. At a battery temperature of 30F, the voltage should be at least 9.1V.

 

[Jetronic]

and at 9.1V, it's questionable if the car starts without error messages. You don't want to sink that low in a current car under actual starting conditions.

 

[atikovi]

i put it on a 10 amp auto charger and it charged up to 13.25 volts . the SOC was 98% while he SOH was 34%. 350 amp from listed 600 amp battery .

350 amps is plenty to start a Hyundai. Certainly more than your jump pack puts out. Kid probably left something on. Put a battery maintainer/desulphator/reconditioner on it for a week or two and you will probably add another 100 amps to that battery.

 

[JHZR2]

5.5v is worse than a shorted cell.

Letting an alternator attempt to charge a battery that low isn’t good for it.

voltage and capacity varies a lot in cold weather. If the battery is discharged too low, the electrolyte can also freeze, changing ratings significantly as it melts and the battery warms.

Replacement for a 5 year old battery that went that low is prudent, especially if your kid doesn’t know how to handle these things themself.

 

[CarLuver]

went back to garage and retested the battery after its sat overnight. odd thing is that its still over 13 volts. after restesting pretty much the same results . very odd battery

 

[willbur]

100A is a easy test to pass. Apply a load at 1/2 of the CCA rating for 15 sec and monitor voltage. At a battery temperature of 70F the voltage under load should be at least 9.6V after 15 sec. At a battery temperature of 30F, the voltage should be at least 9.1V.

Thanks-good to know. I use 10 v using the starter an indicator of a strong battery.