Battery keeps dying but Autozone said they couldn't test the alternator
 

Hello! I searched through other forums for this question and it seems battery issues are pretty common. But, I wanted to tell my specific issues to see if it triggers any thoughts of what it could be from any of you very smart people.

Over the past year, my battery dies if the car has been sitting for a week (replaced the battery maybe a year and a half or two years ago). Kind of didn't think much of it because weather here in Texas fluctuates so violently and it had been sitting for while etc. Car has about 90k miles on it, just FYI.

Now it's dying basically overnight. A couple of weeks ago I took it to Autozone and they tested the battery. They said the battery charge was very low but it was still good. They couldn't test the alternator because they said the battery was too low and that I should drive it for half an hour and bring it back. When I brought it back, the guy said it basically hadn't really charged any and suspected it could be a connection issue. The battery had become loose in the brace and therefore the connections were also loose. I tightened those down, borrowed my dad's battery charger to give it a full charge and hoped for the best.

Last night, my car had been sitting for a couple of days so I wanted to check that it would start. It was dead but started IMMEDIATELY after I put the jumper cables on and tried starting it again. Cables had been on for maybe 10 seconds before I tried to start it, leading me to think it was just barely dead. I drove it for 10 minutes or so, including time on the highway, and parked it. This morning, I tried to start it when leaving for work and it was dead again -- same thing happened: popped on the cables, turned the ignition and it started immediately.

A couple of notes:

1. The battery light has never come on.
2. For a while (at least a year), the headlights kind of flicker (dim for a split, split second) seemingly randomly while driving at night at about 3-5 minute intervals. It's probably not enough for anyone to notice but I notice it. Not sure if this is connected.
3. It has never died while driving. And, so far, I haven't had to jump it if it's been sitting at work for the day. Seems to need to sit for at least 12 hours.

Any thoughts on this? I was hoping to go to a mechanic armed with some info prior to them just trying to stick a new alternator in it (which might be the cause).

Thanks so much for any help on this!

I, too, have been chasing a battery drain on my fit and my wife's accord. All connections are tight. Added more grounds.

Decided to look at the fluid level. Some cells were low. So i topped both batteries off with distilled water and recharged with my battery tender. So far so good.

Double check your battery. See if its low on fluid or its leaking acid.

Quick alternator test would be to start the car. Start turning on accessories one at a time. If the headlights or lights keep getting dimmer and dimmer, your alternator is not keeping up with the extra load and is dying. It's failing to charge your battery.

yah, sounds like your alternator might be shot. also id clean your battery terminals (both cable side and battery terminal posts) if they were loose with a wire brush and 400 grit sand paper and put some contact grease on them.

if u have any aftermarket electronics on your ride, now be a good time to remove them for testing purposes.

Check the alternator fuse link near positive terminal may be corroded!!

Thank you all! I appreciate your help. Unfortunately, it turns out AutoZone was wrong and it was just a bad battery. Hashtag eye-roll.

You can also have a dead cell in the battery. Happened to me with the OEM battery: lasted 1.5 years, then it discharged very fast and I got stuck a couple of times...

happy motoring genslay. GL

That's due to there NOT being enough load in the electrical system to tell the Electronic Load Detector to make the alternator charge. Third party stores and shops do this way too frequently because they do not know of this feature.

Put a volt meter on the battery posts, start the car and put the high beams on. The alternator WILL charge at around 14 volts or so if it is good.

Here is what everyone should have for about $2.00:

https://www.aliexpress.com/item/2016...788670717.html

Stick it in any accessory (cigarette lighter) socket and read the alternator voltage while you drive. With it you can tell if the alternator is charging as expected.

We probably have 8 or 10 of them around here and at the airport. I have used then on everything from cars, to trucks, to John Deere tractors, to airplanes, to motorhomes. I can not say that they are accurate to the 1/10 of a volt but it sure can tell the difference between 14.0 volts charging and 12. 0 volts almost dead battery.