Every summer since I've owned this car, I usually run into a battery problem. I live in Florida and I know the heat is killer on the batteries. I've had this ACDelco battery since June 2019. It ran fine up until last week when it was dead. It had less than 2 volts according to the multimeter. It couldn't be jumped that I had to have it towed to the shop I purchased the battery. They performed load testing on the battery and alternator and found nothing. They also tested for a parasitic drain and found nothing. They charged the battery and everything was fine.

Today it's dead again and is at less than 8 volts. I'm waiting for my jump box to charge to see if I keep jump it.

Battery is less than a year old.

Battery cables/connections are less than a year old.

Terminal posts are a few weeks old

Alternator is 6 months old.

No stereo or system hooked up. No obvious parasitic drains. I'll probably have the shop look at it again and have them replace it since it has a 3 year warranty but this is ridiculous.

 

Could be a bad diode in alternator. You can try by disconnecting alternator cable at battery when not in use.
https://itstillruns.com/can-alternat...y-7605315.html

 

Is there a way to test the alternator for a bad diode? Would it show up in load testing? The alternator was load tested.

 

Scroll down to number 3 to check diode.

https://axleaddict.com/auto-repair/A...g-System-Tests

3. Checking for a Bad Diode

Usually, a bad alternator diode will cause your headlights or instrument panel lights to flicker or dim and, sometimes, drain battery power overnight, or in minutes.

* To check for a possible bad alternator diode, switch your voltmeter to a low setting on the AC (alternating current) voltage scale.
* With the engine running, touch the meter probes to the battery terminals.
* Your voltmeter should read 0 AC volts.

Any amount of AC voltage would indicate a bad diode, so you'll need to replace the alternator.

 

I am curious about how this went. There are so many different things that can drain a battery. For his sake, I hope it was the alternator.
DR.K.

 

Sorry, I meant to respond to this sooner. I had the shop I brought the battery from load test the battery and test the diodes again since that was warranty. Both tested fine.

Here's were things get weird. After I wired in my fan controller all of my battery issues went away. For the past week plus my car has started on the first turn of the key with zero issues. Battery voltage has held at 12.5-12.8 and alternator 14.5-14.8.