which battery testing method to trust

[WhyMe]

i am working on a 2014 rav4 for some friends. they were told by the dealer that their battery was bad. its the original. i asked them if they gave them any paperwork showing a test and they said no. so i tested it with my 100 amp style tester and it showed 400 amps. the battery list 550 CCA. curious i took it to a parts store and had them check it. it showed the battery bad. i think it was a midtronic they used .

they have never had issues with this battery and the dealer telling them it was bad was a surprise to them . now i am curious which one i should believe, my tester or the dealers and auto parts.

which one is more accurate ?

 

[ZeeOSix]

5 year old battery ... wouldn't be a bad idea to just replace it if different tests are giving different answers.

 

[MParr]

I test mine with a multi-meter. It has always been reliable for me even when the KIA dealership gave me a printout saying that the battery was good. A battery hydrometer works well for batteries that have cell caps. Original battery? Replace it!

 

[Warstud]

What issue is your friend having ?

 

[WhyMe]

Originally Posted by Warstud
What issue is your friend having ?


no issues. they brought it in for a oil change and as part of the check they did the battery.

 

[Warstud]

Originally Posted by WhyMe
Originally Posted by Warstud
What issue is your friend having ?


no issues. they brought it in for a oil change and as part of the check they did the battery.

I'm sure the dealers tester is the best of all...but I don't trust dealerships. So if there's no issue with it starting or needing a jump I would keep the old battery until you do.

 

[andyd]

Run away.from dlr . If you can play 3CDs in a row and still be able to start the engine...

 

[Wolf359]

Throw it on a battery charger and test it again. You could squeeze a little more life out of it.

 

[Dinoburner]

It showed 400 amps for how long? A proper load test involves a certain length of time. At 5 years I agree with replacing or carrying jumpers.

 

[das_peikko]

The best battery test is to measure the voltage while it's cranking the engine.

 

[Dave9]

Considering that Winter is about over, replace the battery now if getting stranded would be an excessive hardship, if there are children, elderly, driving through bad neighborhoods or remote locations without cell service, etc.

If not, and/or they have jumper cables or a portable jump starter power bank and the driver is fit to use it, I'd wait until late fall next year to replace it considering no symptoms starting the vehicle yet.

 

[Tomioka]

If the starter draws too much power when the electrics spazzes out then you know the battery is bad. LS starters can crank at a ridiculously low voltage but will pull voltage where it can't power the fuel pump, ECU, etc.

Had a 5.5 year old Odyssey AGM in my Silverado do this and it was time to get a new battery. No charging can ever reverse time on those old lead-acid plates.

 

[ofelas]

If you have access to a carbon pile tester, that would be the way to go.

 

[MasterSolenoid]

OP, I had a similar situation, I tested my battery with a Digital Tester (at Home) and it showed, GOOD - RECHARGE.
Advance Auto tested it with 'same' results.

I would take for 1 hour drives / Alternator working properly.
I would put on Smart Battery Charger all day.

1) Next day, using a multi-meter, the voltage would be 12.2 / I was expecting 12.6+
2) Voltage while starting the engine would drop to 8.7 / I believe minimum should be 9.6
3) I checked the electrolyte with a hydrometer and all six cells showed FAIR

Well, although the Battery started the engine fine, it was 4 years old, I replaced it / now it's one last thing I think about.

My previous Battery died suddenly with 'no' warning.

 

[Donald]

Ok something is wrong or remembered wrong with the 100 amp battery test that showed 400 amp. I think they are confusing the two tests. The 100 amp load test will read a voltage after 15 seconds. That is used to determine if the battery is good or not. Better is a carbon pile load tester that puts 1/2 the CCA as a load on battery for 15 seconds then measure voltage. Either test should be looking at the temp compensated voltage scale.

The conductance test (Midtronics) needs to be done specifying the right type of battery and the right CCA and compensated for battery temp.

But if the conductance test done properly shows 400 amps then time for a new battery.

 

[E150GT]

I remember an old girlfriend had a 2000 ML320. Dealer said battery was bad. I scoffed. Got stranded a few weeks later with a dead battery.

 

[bbhero]

Originally Posted by MasterSolenoid
OP, I had a similar situation, I tested my battery with a Digital Tester (at Home) and it showed, GOOD - RECHARGE.
Advance Auto tested it with 'same' results.

I would take for 1 hour drives / Alternator working properly.
I would put on Smart Battery Charger all day.

1) Next day, using a multi-meter, the voltage would be 12.2 / I was expecting 12.6+
2) Voltage while starting the engine would drop to 8.7 / I believe minimum should be 9.6
3) I checked the electrolyte with a hydrometer and all six cells showed FAIR

Well, although the Battery started the engine fine, it was 4 years old, I replaced it / now it's one last thing I think about.

My previous Battery died suddenly with 'no' warning.













^^^^^^^^^

This... Better to replace and move on..

 

[The_Jeff]

Midtronics themselves say that 60% of CCA is marginal and 50% is the replacement criteria. By that standard this battery is fine.

I would be interested to see the little print out the tester gives. If the dealer won't give up the printout, they are up to shenanigans.

 

[Patrick0525]

I used the Ancel BA101. It said Replace and so did PepBoys' test system.

I am not a mechanic but I trust the conductance testers since it will not leave me stranded. Old school load testers cannot measure milli ohm resistance and calculate CCA.

This is new the Sears gold DieHard flooded cell. It is a 24F. The pic shows 500 CCA but the battery is really around 710 CCA.

 

[Donald]

Originally Posted by Patrick0525
I used the Ancel BA101. It said Replace and so did PepBoys' test system.

I am not a mechanic but I trust the conductance testers since it will not leave me stranded. Old school load testers cannot measure milli ohm resistance and calculate CCA.

This is new the Sears gold DieHard flooded cell. It is a 24F. The pic shows 500 CCA but the battery is really around 710 CCA.

Places that sell batteries went to the conductance testers not because they are better but rather because you can test a battery that is not fully charged.

A carbon pile tester does the best job assuming the battery is fully charged.