Dead battery

[rchurch5945]

I've got a 1996 2 door 2 wd Tahoe. I'm in the process of lowering it 4" and rebuilding the suspension. I have it in my shop up on jackstands. I don't have a lot of extra time, so I've been working on it off and on for the past 4 months. After I finished the rear suspension, I decided to crank it up just for the heck of it. The battery was completely dead. I thought, "no big deal" and disconnected the cables and put the charger on it overnight. The next day I reconnected the cables. JUST AN FYI- when I reconnected the battery the emergency flashers started flashing and it wouldn't even try to start. After researching some, I found out it is the anti-theft. Turn the key to the on position, leave it on for 10 minutes, turn the key off for 20 seconds, and it starts.

So, back to the battery. Started it up, let it run for a while and turned it off. Thought everything was ok. Came back the next day - completely dead again. Disconnected the cables again, recharged it over night, and tested the battery. 12.7 volts. Left it disconnected for a week, tested it again, 12.4 volts. Battery seems to be good. Hooked the cables up, started it, tested it while it was running - 14.4 volts, so the alternator is charging. Next day - dead.

I noticed when I was connecting the positive cable it sparked big time. Not just the little spark when connecting a battery. This tells me I have a short somewhere maybe? Is there something particular about these Tahoes I can check? I'm not looking forward to just tracing out wires and hope I find it.

I drove it daily for about 6 months before putting it in my shop and never had any problem with it. HELP!

 

[wjburken]

I've got a 1996 2 door 2 wd Tahoe. I'm in the process of lowering it 4" and rebuilding the suspension. I have it in my shop up on jackstands. I don't have a lot of extra time, so I've been working on it off and on for the past 4 months. After I finished the rear suspension, I decided to crank it up just for the heck of it. The battery was completely dead. I thought, "no big deal" and disconnected the cables and put the charger on it overnight. The next day I reconnected the cables. JUST AN FYI- when I reconnected the battery the emergency flashers started flashing and it wouldn't even try to start. After researching some, I found out it is the anti-theft. Turn the key to the on position, leave it on for 10 minutes, turn the key off for 20 seconds, and it starts.

So, back to the battery. Started it up, let it run for a while and turned it off. Thought everything was ok. Came back the next day - completely dead again. Disconnected the cables again, recharged it over night, and tested the battery. 12.7 volts. Left it disconnected for a week, tested it again, 12.4 volts. Battery seems to be good. Hooked the cables up, started it, tested it while it was running - 14.4 volts, so the alternator is charging. Next day - dead.

I noticed when I was connecting the positive cable it sparked big time. Not just the little spark when connecting a battery. This tells me I have a short somewhere maybe? Is there something particular about these Tahoes I can check? I'm not looking forward to just tracing out wires and hope I find it.

I drove it daily for about 6 months before putting it in my shop and never had any problem with it. HELP!

How old is the battery? Might be worth your time to get it tested. You might have a bad cell.

 

[Tonyrodz]

How long did you let it run for? Imo, letting it idle doesn't give the battery the necessary charge that it needs to maintain it. Driving it is much better to charge it. I know it's on jack stands. Might be better off to leave it on the charger, then to leave it connected to the truck. You have a few constant draws on the battery--clock, pcm etc, even tho they're small, they're still a draw that adds up.

 

[OR VietVet]

Sounds like a sulfated battery that is old enough and sat long enough that now it will not hold a charge. Replace it, make sure connections are good and tight and clean at both ends of the cables and then deal with anything else that may come up. The battery is the heart of the electrical system. It has to be up to *****.

 

[swathdiver]

Sounds like a sulfated battery that is old enough and sat long enough that now it will not hold a charge. Replace it, make sure connections are good and tight and clean at both ends of the cables and then deal with anything else that may come up. The battery is the heart of the electrical system. It has to be up to *****.

^^^ THIS!!! ^^^^

If the truck is not going anywhere for a while, you might kick the can down the road a bit and get this:

https://www.amazon.com/BatteryMINDe...teryminder&qid=1584988973&s=automotive&sr=1-7

 

[OR VietVet]

Good call James. Forgot about the battery minder.

 

[BG1988]

if you going to store it for a long time pull it from the truck and bring it inside


battery maintainer is not required you can store it for a month or two no issue

if it's sitting cold or heat cycles will be bad for it and it will drain out.

14.4v is a little low for the truck it should be at 14.8-15v when charging check the terminals and clean them it could be dirty on the connectors (i took my terminals apart they were pretty dirty causing things not to operate correctly my voltage was too low only 14.3volts on a cold start and it was all over the place) now it's at 14.8 14.9volts on a cold start and you bet i bought new ones for nothing(but keep them as a spare)


i don't know if you have side posts or not but you can pick up a new AGM battery for 150$ at walmart

 

[swathdiver]

if you going to store it for a long time pull it from the truck and bring it inside


battery maintainer is not required you can store it for a month or two no issue

if it's sitting cold or heat cycles will be bad for it and it will drain out.

14.4v is a little low for the truck it should be at 14.8-15v when charging check the terminals and clean them it could be dirty on the connectors (i took my terminals apart they were pretty dirty causing things not to operate correctly my voltage was too low only 14.3volts on a cold start and it was all over the place) now it's at 14.8 14.9volts on a cold start and you bet i bought new ones for nothing(but keep them as a spare)


i don't know if you have side posts or not but you can pick up a new AGM battery for 150$ at walmart

It's not holding a charge Brent. Something is wrong with it. There's a good chance that the tender will revive the battery.

 

[BG1988]

It's not holding a charge Brent. Something is wrong with it. There's a good chance that the tender will revive the battery.

ahh better to replace it then try to "fix it"...


unless you able to take it apart and rebuild it, he should check the acid levels if it's not sealed( gotta use safety equipment ) some auto store do have battery fluid.

i tried fixing mine it only bought me a few more months...and stalled in the middle of traffic because of it .. I know for the future it's never worth the risk in my area since our speed limits are 40-60 mph.. luckly it stall on a left green arrow and not on a Yield.. i think the momentary drop to 9volts was a internal short as it fired right up then i went to Walmart and bought a new one

 

[NoReverseYukon]

It could be stratified. You didn't mention if it was maintenance-free or not.
If so, or if you can keep it from leaking on you, it might be worth a shot at mixing up the electrolyte by shaking/tipping the battery back and forth. Mine came back to life after I did that. Just be careful and cover any caps with a rag to protect yourself.