Battery Dead... Again

[dreamingat30fps]

So I just replaced the battery in August. Bought one from Autozone AGM similar specs to the OEM one. Usually keep it on the battery tender since I don't drive it everyday.

Anyways last week I drove it most of the week as my daily was out of commission. Then it sat for maybe 2 or 3 days max. Went to start it and it was totally dead, didn't even click nothing.

So I take the battery back to Autozone, guy there tests it and said its beyond dead. Gave me a new one. So I got home installed everything got my multimeter and I was reading 12v at the battery with ignition off (as it should be) then with the engine on it was like 13v and reving to about 2k it would fluctuate between 13-14v.

So is this ok or is there something up with the alternator? If not any idea why the battery would die so quickly?

Thanks

[XMetal]

See post #72 of this thread => http://www.zpost.com/forums/showthread.php?t=745266

[chickdr]

I read the new issue of CR last night and they mentioned the group 48 AGM in particular as having big problems. They said CR always recommends Duralast batteries, but obviously something is amiss with this model. They even tried a second batch of batteries in case the first set was a fluke- same issues. I am glad I went with O-Reilly's non AGM which has done well in the 3+ years I have had it.

[dreamingat30fps]

Well I guess that sucks, although bad alternator would suck even more. I don't drive the car enough to justify buying a new battery so we will see how it goes with the replacement. It was a different color than the original one that went bad so hopefully its a different batch.

[chickdr]

You may consider asking for a non AGM version as a replacement if this one goes bad quickly...

[XMetal]

I got my Autozone H6 AGM last June. It hasn't gone bad yet, but I've been monitoring it and had noticed that its charge holding capabilities haven't improved over the flooded battery that it replaced. It may even be slightly worst.

I drive the car at least 3 to 4 times a week - Just went out to measure the battery and it's only reading 12.20V with no load It was last trickle-charged about a month ago and I usually do it at least once per month on the car. I'm going to try out not trickle charging it for a few months and see what happens.

[dreamingat30fps]

Originally Posted by XMetal

I got my Autozone H6 AGM last June. It hasn't gone bad yet, but I've been monitoring it and had noticed that its charge holding capabilities haven't improved over the flooded battery that it replaced. It may even be slightly worst.

I drive the car at least 3 to 4 times a week - Just went out to measure the battery and it's only reading 12.20V with no load It was last trickle-charged about a month ago and I usually do it at least once per month on the car. I'm going to try out not trickle charging it for a few months and see what happens.

Is that bad? The new one reads 12v (sorry got a cheapo multimeter) and my daily driver which is a 2014 also reads 12v. My suv which is starting to have battery issues (a 2008) is reading 11v.

[XMetal]

Attached is an example chart that I've seen for batteries...so draw your own conclusion.

As a comparison, the Bosch AGM battery on my X5 behaves very close to the numbers on the chart. After a full charge (on a trickle charger), it measured about 13.2V. And after sitting for about 2 weeks undriven, I've seen that it would stayed at about 12.65V - 12.70V and it really just stayed at this level even when I drive it 3 to 5 times a week. On the other hand, the Autozone AGM would only show about 12.65V after a full charge with the same trickle charger. After sitting a week or so, that Autozone battery would drop down to about 12.40V. So, right off the bat, the Autozone AGM doesn't compare well against the Bosch AGM

[KevinC]

I've also read about the Duralast battery issue on CR. I have that battery in my ZHP, but it's been there for almost 3 years, and this seems to be a very recent issue.

Just recently replace the Z4MC battery and went with the Napa AGM battery. It has identical specs to the BMW OEM battery, which are slightly different than the Duralast model, so pretty sure they're not the same exact battery. All is well thus far.

If anybody buys from Napa, be sure to ask for AAA discount (10%).

[Caddyshk]

Who makes the Private Label AGM Batteries for Napa & AutoZone? East Penn, Exide? Exide makes the OEM for BMW.

[Jumbosock]

My car has been killing batteries since I got the car 4 years ago. Any battery. I haven't checked for a parasitic electrical drain because I just keep it on a trickle charger. I need to figure it out. Maybe you have a drain.

When I sit in my car after turning it off, after a few minutes I can sometimes hear the CD start spinning in the factory stereo. Does anyone experience that?

[Taylorguy74]

Originally Posted by Jumbosock

My car has been killing batteries since I got the car 4 years ago. Any battery. I haven't checked for a parasitic electrical drain because I just keep it on a trickle charger. I need to figure it out. Maybe you have a drain.

When I sit in my car after turning it off, after a few minutes I can sometimes hear the CD start spinning in the factory stereo. Does anyone experience that?

Not so much the stereo, however anytime I open the door, my nav cd starts spinning up.

[keeton]

Originally Posted by Caddyshk

Who makes the Private Label AGM Batteries for Napa & AutoZone? East Penn, Exide? Exide makes the OEM for BMW.

Johnson Controls. Interestingly, the "BMW" battery in my '07 Z4 had the identical case to the AutoZone Platinum (made by J.C.) battery I replaced it with.

[Caddyshk]

Originally Posted by keeton

Johnson Controls. Interestingly, the "BMW" battery in my '07 Z4 had the identical case to the AutoZone Platinum (made by J.C.) battery I replaced it with.

Not surprising. Must tender out the Battery business frequently for price. I purchased a replacement OE a couple of years ago and its an EXIDE. EXIDE is restructuring under chapter 11 so I'm not clear who is supplying BMW at the moment.