What's considered good battery volts?

[mosaud1998]

Costco has a straight replacement warranty only, not the long-term prorated warranties which sound great but are better for marketing than any real benefit, and lock you into another purchase with a credit amount.

If things haven't changed, with Costco, if the battery craps out within the 36-month period (used to be 42), bring it back and they'll refund your money, no questions asked. It's not a credit, and doesn't have to be applied toward buying another battery, just straight dough. The catches are that an active membership must be maintained during that period, and not every warehouse stocks every size. Also, Costco Interstates can only be handed by Costco, not other Interstate dealers, but overall, it's a cheaper way to get a Clarios than going elsewhere with a different label.

I've read about some people trying to game the system, and getting a fresh one every ~35 months of so, but since it's a membership, and every purchase is logged, they probably have some internal controls to discourage it. They track returns in general, and will take action against abusers, like a lot of retailers do nowadays.

Welp, my battery is fine. I guess it's either a ground or a vacuum leak.

 

[Snagglefoot]

You’ll find out next week.

 

[Creekside]

A 12v lead acid battery has 6 cells with 2.1v of potential energy in each cell. That’s where your 12.6v on a fully charged battery comes from. Then you bring state of charge into the mix and you’ll see that a battery with 12.1-12.2v is considered 0% state of charge where 12.6v is 100% state of charge. Someone correct me if I’m wrong here, I’m reaching back to high school automotive technology and college classes.

 

[Snagglefoot]

From actual measurements with a good quality voltmeter I get 12.6 volts from my new AC Delco battery and 12.1 Volts from my 4 year old Everstart. The battery with 12.1 V still starts fine. I believe once it goes below 12, you will get weak starts if at all.

Then you can get into acid density numbers and the battery measuring devices that put a load on the battery.

 

[Davejam]

A 12v lead acid battery has 6 cells with 2.1v of potential energy in each cell. That’s where your 12.6v on a fully charged battery comes from. Then you bring state of charge into the mix and you’ll see that a battery with 12.1-12.2v is considered 0% state of charge where 12.6v is 100% state of charge. Someone correct me if I’m wrong here, I’m reaching back to high school automotive technology and college classes.

This is incorrect. 12.1-12.2V is considered ~30-40% SOC at 78F.

 

[mosaud1998]

You’ll find out next week.

View attachment 44194

Ahhh ****

 

[Fattylocks]

Eight fresh d-cell flashlight batteries will give 12 volts or better. It's not the volts that crank the starter. It's amps, best checked with a load tester.

 

[Wolf359]

A 12v lead acid battery has 6 cells with 2.1v of potential energy in each cell. That’s where your 12.6v on a fully charged battery comes from. Then you bring state of charge into the mix and you’ll see that a battery with 12.1-12.2v is considered 0% state of charge where 12.6v is 100% state of charge. Someone correct me if I’m wrong here, I’m reaching back to high school automotive technology and college classes.

Electrical engineer here. See my previous post. Check various state of charge charts and read the disclaimers. That's why most people here are WRONG because they're just reading the voltage and not accounting for the other factors such as temperature and load. It's the no load voltage of a battery at rest to determine state of charge at 70 degrees. A battery connected to a car in the winter is not at 70 degrees and not at zero load. That's why the battery was fine even though the voltage was reading low. Had a load on it and the lower temperature gives you a lower voltage.

 

[michael007]

The catches are that an active membership must be maintained during that period

I think I read on another forum someone had emailed costco asking this. They replied they'd honour the 36 month warranty if your membership wasn't active.

 

[michael007]

Welp, my battery is fine. I guess it's either a ground or a vacuum leak.

I think you've got a ground problem with that green cable in the engine bay.

Get it fixed sooner than later because it wasn't fun having to tow the car after it failed.

 

[bbhero]

Electrical engineer here. See my previous post. Check various state of charge charts and read the disclaimers. That's why most people here are WRONG because they're just reading the voltage and not accounting for the other factors such as temperature and load. It's the no load voltage of a battery at rest to determine state of charge at 70 degrees. A battery connected to a car in the winter is not at 70 degrees and not at zero load. That's why the battery was fine even though the voltage was reading low. Had a load on it and the lower temperature gives you a lower voltage.

Very, very good post wolf.

 

[RAR]

BMWs are always fussy about their battery.

My 2008 BMW 535xi I used to have had a weak battery around Christmas 2016. It would throw codes, light up warning lights, and signal other errors that I knew weren’t really going on (like a flat tire with 0 lbs of air).

I got a NAPA battery for it, coded it with my Carly tool, and every issue and warning vanished.

Bear in mind that the old battery was still able to start the car and my meter showed the alternator was putting out the required volts... just that it wasn’t holding up it’s end of the work any longer. It WAS the OEM battery, so it lasted 8 years and 100k miles. No idea how that replacement held up as I sold it the next October.