2008 Sierra Denali battery issues

[BrandenG1]

I’ve been having to jump start my 2008 GMC Sierra Denali several times a day recently. 2 out of the 9 times I’ve started it today I had to jump it. I went to O’Riellys and my battery read 12.4 volts and alternator read 14.7 volts. I do notice when I drive occasionally the battery will read 15 volts then 12 within a 5 minute span. What should I look into? Voltage regulator? 

[garagerog]

How old is the battery?  Just because the resting voltage is ok at 12.4V, you'll need to load test the battery to confirm it's copacetic.

[BrandenG1]

The sticker on the battery shows 11/19. 

[newdude]

1 hour ago, BrandenG1 said:

I’ve been having to jump start my 2008 GMC Sierra Denali several times a day recently. 2 out of the 9 times I’ve started it today I had to jump it. I went to O’Riellys and my battery read 12.4 volts and alternator read 14.7 volts. I do notice when I drive occasionally the battery will read 15 volts then 12 within a 5 minute span. What should I look into? Voltage regulator? 

 

 

The charging system will fluctuate under normal operations.  The ECM and BCM control the entire charging system.  

 

Did the parts store actually load/diagnostic test the battery?  Or did they just read it with a little handheld tester?  

[BrandenG1]

I don’t believe he put it under a load. I never turned the key or started the truck. I’m going to buy a new battery today since this one is going on 5 years old. Thanks guys I’m new to all this and clueless. 

[richard wysong]

Yep sounds like the battery is toast, my local NAPA told me they do not make a 5 year battery any more, just a 2 year. NAPA bats are Deka which I have never had 1 last more than a year, Walmart or Interstate are my choices, Duralast, Diehard etc are made by Excide

Edited July 24, 2024 by richard wysong

[CamGTP]

Napa sells batteries with 18 month, 24 and 36 month warranties.

 

When there is really only 3 people that make batteries for everything, you don't have much to choose from. You're basically buying what the sticker says and what warranty you want on the battery. I've run nothing but Napa batteries for the last 15 years, they've treated me just fine in every vehicle I've owned. Sometimes you get bad batches.

[MaverickZ71]

I get 4 years out of a WalMart Everstart MAXX battery if I charge it 3-4 times a year, and only 2 years out of it if not hooked to battery charger occasionally. Truck's charging system tests ok. 

 

A damn sight different than 30 years ago, when I could routinely get 9 years out of a 4-year battery, without ever hooking it to a battery charger--just kept the cells full of distilled water. The more things change, the more they cost, and the worse they get. 

[richard wysong]

Has anyone tried the rejuvenation trick I see on the web? I watched a video for half an hour only to find they wanted $15 to let you know how to do it. Probably involves hooking the battery to a welder. There are also chargers that "pulse" the current to remove sulfation of the plates, anyone tried them?

[MaverickZ71]

5 hours ago, richard wysong said:

Has anyone tried the rejuvenation trick I see on the web? I watched a video for half an hour only to find they wanted $15 to let you know how to do it. Probably involves hooking the battery to a welder. There are also chargers that "pulse" the current to remove sulfation of the plates, anyone tried them?

My Schumacher battery charger says it automatically detects and charges through sulfation. It has a digital percentage charged meter--on a sulfated battery, it will start to charge, then hum for awhile, then the percentage charged meter climbs fast after it's busted through the sulfation. 

[richard wysong]

Worthwhile investment ?

[BrandenG1]

O’Riellys claims the battery is good again. I just plugged in my portable cigarette lighter tire pump and within 5 minutes the battery was dead. 

[MaverickZ71]

33 minutes ago, richard wysong said:

Worthwhile investment ?

Totally. It's about 20 years old, but between servicing all of the batteries in the family/friends fleet of vehicles/mowers, it's paid for itself. If memory serves, it was the best battery charger that O'Reilly Auto Parts sold back in the day. 

[richard wysong]

Sounds like it is time for a new battery Branden