IMO the quality of all new replacement car batteries has gone way down. I purchased my Chrysler new in 2020 and the original battery is still going strong. When I purchase new batteries they last less time. Come replacement time I'll just bite the bullet and buy a DEKA AGM battery, Those have been proven to last a long time. Unbeknownst to most there are only two large domestic battery manufacturers that make 95% of the brands In the USA.. They are Johnson controls and Exide.
------------------ " THE BLACK PARALYZER" -87GT 3800SC Series III engine, custom ZZP /Frozen Boost Intercooler setup, 3.4" Pulley, Northstar TB, LS1 MAF, 3" Spintech/Hedman Exhaust, P-log Manifold, Autolite 104's, MSD wires, Custom CAI, 4T65eHD w. custom axles, Champion Radiator, S10 Brake Booster, HP Tuners VCM Suite. "THE COLUSSUS" 87GT - ALL OUT 3.4L Turbocharged engine, Garrett Hybrid Turbo, MSD ign., modified TH125H " ON THE LOOSE WITHOUT THE JUICE "
I hope I just had bad luck on a Deka AGM 95R. It was only in service less than 3 years somehow the wife or kid was able to drain the battery to 4 volts, I was able to revive it but this is like the 4th or 5th time I've had to do this. Tested with a battery tester and it's coming out weak
I have 3 other Deka's, 1 in my ride 5 years albeit still puttingit back together, the others are over 10+ years old. East-Penn does quite a bit for lead recycling, not sure about Jonhson Controls or Exide. I miss the green eye Delco's, kind of predictable but reliable.
Automotive batteries that are drawn down to a low voltage can suffer from sulfation. They can usually be restored to like new condition with a battery desulfator. I have successfully restored some automotive batteries this way
------------------ " THE BLACK PARALYZER" -87GT 3800SC Series III engine, custom ZZP /Frozen Boost Intercooler setup, 3.4" Pulley, Northstar TB, LS1 MAF, 3" Spintech/Hedman Exhaust, P-log Manifold, Autolite 104's, MSD wires, Custom CAI, 4T65eHD w. custom axles, Champion Radiator, S10 Brake Booster, HP Tuners VCM Suite. "THE COLUSSUS" 87GT - ALL OUT 3.4L Turbocharged engine, Garrett Hybrid Turbo, MSD ign., modified TH125H " ON THE LOOSE WITHOUT THE JUICE "
Automotive batteries that are drawn down to a low voltage can suffer from sulfation.
The clock or other parasitic battery drains can kill the battery - keep the battery fully charged or disconnect the negative cable. In average, my batteries last 8 to 10 years...
As 'Interstate Batteries', I chose at my local auto shop who carries batteries known for their long service life... I try to buy the highest cold cranking amps (CCA) batteries I can. On the Fiero, I changed to top posts and side posts as I 'hate' the negative side post location..
------------------ Original Owner of a Silver '88 GT Under 'Production Refurbishment' @ 136k Miles
I'll report back the outcome of attempting to save this battery. It was @ 12.3 volts yesterday afternoon, tonight 11.7. Yes I might have some other gremlin lurking on the car.
Dennis thanks for the tickler about de-sulfication, quite likely what my battery has going on.
I found this little charger that can do more than my older charger, technology has changed and hopefully this pans out.
As far as exide, Johnson Controls, East Penn I would do East Penn, Exide, then Johnson. Just my 2 cents
[This message has been edited by Stingray92 (edited 11-03-2025).]
So i let the battery charge overnight, never did get the solid green light of full charge. I did the repair function this evening it took a little over 3 hours and when I tested it was pleased, the result is now good.
I'll see how it goes, hopefully this was just a one off.
Short update reinstalled the Deka last night 12.5 volts, car started perfectly.
On a hunch I checked the voltage thus evening and it was down to 12.05. I'm not sure why it dropped so much, my other Deka right at 12.5 and it's 4 years old.
I'll test it again in the morning. For what it's worth I did check for battery drain, this car is at .3 amps. That seems well in range for a idle/shut off vehicle.
Agreed 300 ma is a lot, I should have prefaced the car the battery I'm refrencing is in is a 2016 Hyundai Genesis.
The voltage of the battery this morning was 11.8, this evening was 11.9. Car started on its own power and I let it run for 30 minutes ~. Afterwards I checked the voltage waiting about 15 and it was at 12.2 (14.4 w/engine running).
Redid the drain test and it held steady at .255, I agree this seems high but I don't know what the baseline should be for this car but it has a bunch more circuits than our Fieros.
Anyway I would likely still go Deka depending on price/experience.
Redid the drain test and it held steady at .255, I agree this seems high but I don't know what the baseline should be for this car but it has a bunch more circuits than our Fieros.
Even so, how many of those circuits should be active while your Genesis is not running? I'm guessing your battery drain is too high, but I certainly don't know for sure.
. It was only in service less than 3 years somehow the wife or kid was able to drain the battery to 4 volts, I was able to revive it but this is like the 4th or 5th time I've had to do this. Tested with a battery tester and it's coming out weak 
