AGM battery in BMW E46 or not? (OE was not AGM)

Status
Not open for further replies.
Joined
May 9, 2003
Messages
9,282
Location
Fayetteville, NC
Car is a 2005 BMW E46. Factory/regular battery is a traditional (not AGM) battery.
I've read about some advantages of AGM batteries.

Advance Auto and Autozone both have AGM (and traditional) batteries for my car (H7 size).

Are there any disadvantages or problems in using an AGM battery in a car that didn't use an AGM battery from the factory?
Are there any special maintenance requirements when using an AGM battery?


**BTW Both AZ and AA have disclaimers when searching for batteries for my car: IDK if they'll refuse to install this:

"REQUIRES PROFESSIONAL INSTALLATION; Battery is vented to outside; Computer must be reset; See manual for safe installation; 30 minute Install; Battery in trunk; DO NOT attempt to install batteries in this vehicle. The battery information must be reset in the power management system.; Please inform customers and recommend that they have their battery replaced at an authorized BMW dealership/shop."

I am pretty sure "The computer must be reset / battery information must be reset in the power management system" part is non-sense, as no such procedure is needed in an E46 (I've had regular batteries installed before at Walmart but not at AA or AZ). I think all that resetting/reprogramming stuff is only for E90 gen and later.
 
AGM batteries are perfect for bmw's just have it registered and you are good to go. Had 3 of them.
 
Originally Posted By: kpatter
just have it registered and you are good to go.

If his E46 is anything like my E39, there is nothing to register, but he will lose some of his settings (radio, avg. mpg, trip meter, etc.), unless he connects another source of power while he swaps the battery out.
 
AGM are good batteries. I would get a Odyssey battery. They are expensive but are dependable and have a 7 year warranty. Stay away from Auto Zone batteries. Had bad experiences, but that is me.

Good hunting!
 
Originally Posted By: kpatter
AGM batteries are perfect for bmw's just have it registered and you are good to go. Had 3 of them.

His car does not require battery registration.
 
The AAP AGM, which is a JCI, has something in it to limit charging voltage. I think they've recognized this will help it in retrofit situations.

I would get one if the price differential isn't substantially different.

Also, having a trunk location and periodically checking it / making sure it is topped up, raises the possibility of a very long life.
 
Thanks for the comments so far.
(and no, my car doesn't need any type of "registering")

Price difference is about $20 more for the AGM vs regular.

I think I will go with the AAP AGM; I can order online, and I have an AAP close to me. I found an online coupon for AAP too.

I already called the local AAP about the disclaimer and the guy said he has no problem doing it if I can bring the car in with the panels removed that covers the battery area. (which I can do).

However as the car doesn't start at all right now, I have to jump the car using my jump starter/booster pack (The car has engine bay terminals for charging/jumping). If that doesn't work, I might have to go get the battery and install it myself.
 
Last edited:
Go get the battery yourself and hand in the current one while you're at it.

Better not to have the alternator trying to charge a faulty battery and it sounds like you have to do most of the work yourself anyway.

You can also put the new battery on a charger before installing it.
 
I had an 03 325xi whose battery [censored] out too. Engine bay terminals were junk probably from time, if not hack mechanics. Point is, you can install it yourself in 15 minutes. Jump the car from the trunk. Fastest way to do it. I wouldn't risk jumping it and then taking it to the store unless you reallly don't want to install it yourself.
 
depending in the alloy used they are very close to wet.
some actually want slightly higher voltage.
the optima redtop in my workvan is over 15 years now.and there were no agm auto batteries when it was made.
Originally Posted By: saginawmale50
I would not. AGM batteries have different charging profiles than regular wet-cells. Its really easy to burn one up by overcharging. Stick to OEM spec.
 
be aware that AGM batteries can't hold their charge over long periods of time, I have a 2006 Volkswagen Phaeton which has a regular starter battery and an AGM battery for powering all the extras.

During winter storage, the AGM battery goes completely flat within a few weeks, the regular starter battery still holds more than enough power to start the vehicle even after sitting for a few months.
 
Originally Posted By: alex_at
be aware that AGM batteries can't hold their charge over long periods of time, I have a 2006 Volkswagen Phaeton which has a regular starter battery and an AGM battery for powering all the extras.

During winter storage, the AGM battery goes completely flat within a few weeks, the regular starter battery still holds more than enough power to start the vehicle even after sitting for a few months.

From one Phaeton owner to another, you may want to look into what is causing your drain. I once let mine sit for almost a month (I forgot to connect the Battery Tender) and both batteries were still at a reasonable voltage. Even now, my VPS battery is original to the car!
 
Originally Posted By: rooflessVW
Your car will be fine with an AGM installed. Make sure you charge it before you pop it in.

No registration required.


You sure about registration?

I dropped a group 49 AGM into my E30, of course that didn't require registration. I also coded and upgraded to a group 49 AGM in my 135i.

Since BMWs are often set up to take that larger battery size by default (both cars used the same HW and had a spot already set up to take it by just screwing the mounting hardware in), its a worthy upgrade unless you're super-concerned about weight.
 
Originally Posted By: alex_at
be aware that AGM batteries can't hold their charge over long periods of time, I have a 2006 Volkswagen Phaeton which has a regular starter battery and an AGM battery for powering all the extras.

During winter storage, the AGM battery goes completely flat within a few weeks, the regular starter battery still holds more than enough power to start the vehicle even after sitting for a few months.


AGM actually has lower self-discharge rates than a traditional flooded battery. Therefore you should probably identify the cause of your parasitic losses in the car...
 
Originally Posted By: rooflessVW
Originally Posted By: alex_at
be aware that AGM batteries can't hold their charge over long periods of time, I have a 2006 Volkswagen Phaeton which has a regular starter battery and an AGM battery for powering all the extras.

During winter storage, the AGM battery goes completely flat within a few weeks, the regular starter battery still holds more than enough power to start the vehicle even after sitting for a few months.

From one Phaeton owner to another, you may want to look into what is causing your drain. I once let mine sit for almost a month (I forgot to connect the Battery Tender) and both batteries were still at a reasonable voltage. Even now, my VPS battery is original to the car!


Well I measured the idle drain with everything turned off - my mechanic says everything is fine. Replaced the AGM battery since the original one is now over 10 years old and I disconnect the terminals before storage - the AGM drains faster than the "traditional" battery ....

Even If both batteries are out of the car, the maintenance charger does it's maintenance more often on the AGM ........


If left connected, of course the AGM will be drained fast since the keyless entry system is thirsty for power.
 
Last edited:
I installed the Advance Auto AGM battery in my parents' E46 a couple years ago and there hasn't been any issues. It is also driven infrequently (currently at a little over 50k miles) and has never had to be jumped. I wouldn't hesitate go ahead with AGM.
 
Status
Not open for further replies.
Back
Top