BMW4631

hello,

i have an lci 2008 550i and it seems that my battery doesn t hold charge anymore.

i have the OEM exide discontinued part # 61 21 7 591 085.

My guess is that it is a non AGM battery.

1/ So the question is can i replace it myself by the OEM AGM-92h 61 21 7 639 053 without having to reprogram it,

2/ Is there a replacement to the initial battery that is non OEM and that does not require reprogramming? i just want to avoid a trip to the dealer.

much appreciated!

Thanks!

tonyb635

You might be able to get away with replacing it with something other than you have but it will most likely need to be programmed and registered. I have an 08 535 and got an exact replacement from auto zone for around 150.00 and they installed while I drank my beer and watched... Seven year warranty, fully replaced up to five. Even if you didn't register it and it prematurely failed, just go get it replaced. It sure beat spending 450.00 at the Stealer! If you stay with the same battery all you should do is register it as programming would not be needed.

strobeyprobey

You can get a correct sized battery at an auto parts store. Just don't use their system. Make sure the terminals and the physical dimensions match.

Also maintain the same type of battery, either the flooded lead acid or the AGM that your car has in it now. Both are available from the Auto parts store. Just bought mine from Advanced Auto a few weeks ago (the AGM version size H8) for $124 using $50 off online coupon (do a google search for it).

You are supposed to register, but like Tony says above, saving $400+ from the dealer and many people report going many years without registering the change.

Now if you change from FLA to AGM or vice versa, that does require a coding change in the CAS module.


BMW flooded lead acid batteries are white and the new AGM ones are black. I think the size for the FLA at the auto part store is the 95R.

BimmerFan52

+ 1

As previous posters have stated stay with the type of battery you have. 2008 was sort of on the edge time wise of the move from FLA to AGM. If your battery has white top it is FLA. Black top is AGM.

AGM should never be charged with more than 14.7V during charging. If an AGM battery is registered, the ECM will limit charging in cold weather when the battery charge is very low to 14.7V max. If an FLA battery is registered in the ECM, the charge voltage in cold weather with a low battery can exceed 15V at times, which can damage an AGM battery.

AGM batteries will withstand deep cycling a little better than FLA, but other than that the advantages of AGM over FLA are not huge, and probably not worth the cost of registration if you have FLA now.

BMW4631

ok thanks,

i do have a white top so FLA. Since i want to avoid the trip to the dealer, i might get the closest match at autozone and not register it.

i ll think about it further but now i better understand my options.
Thanks for the suggestions, very much appreciated!

Cheers,

tonyb635

I'm in the second year on mine from AZ. If you decide to get a battery from somewhere Obviously size and orientation of terminals are important but I was told to make sure the Ca and CCa are the same, not less, not more and you can get by without registering it. If you search through this site, you will find that most had no problems with the change and not registering, but a some did. IMO I think the more differences you bring in the more risk of a problem you could have. And of course there is always that peace of mind, you can take it to a indy shop and most of them will register it for you. The registration basically resets the battery profile so it learns the new battery and how to charge it, otherwise it still thinks the old weaker battery is still being used. I believe this is what leads to the premature failure.

BMW4631

Hello,

I ended up getting this one from Advance Auto Parts. It s working great so far without programming.
i ll keep the forum posted on any new developments.
The battery is AutoCraft Gold Battery, Group Size 95R, 950 CCA

Thanks for all the help folks!
Cheers,

JayArras

Without registration, you probably won't know that you should have done it for a year or two when you start scratching your head as to why the battery only lasted as long as it did. I got 7+ years out of my last one.

twh

I just replaced my non-AGM with the same as BMW4631 above from Advance Auto Parts:
AutoCraft Gold Battery, Group Size 95R, 950 CCA 95R/H9: Get best Battery at Advance Auto Parts

If you search Google you should be able to find a $40 off coupon for online ordering

You can register using this (look at the PDF and skip to the Register section since you aren't changing battery type or specs):
http://www.e90post.com/forums/showpost.php?p=11379622&postcount=48

Or this:
BMWLogger – Welcome to BimmerSoftware.com

Be sure and reconnect the vent tube and block the opposite end of the battery vent tube opening.

BimmerFan52

Exactly how battery registration is supposed to extend life is somewhat of a mystery, and I have yet to find an in-depth explanation of the age mapping algorithm and how it achieves longer life.

According to the little information out there, the ECM will charge an older battery harder than a new battery, but since undercharging is the most common reason for short battery life, updating the registration to charge the battery less (all other things being equal) seems counterintuitive.

The only area I see that makes registration critical is a move from a FLA type battery to an AGM type. AGM batteries should never be charged at a voltage higher than 14.7V. In a low ambient temperature if an FLA type battery is measured at a low state of charge, the ECM can direct the alternator output to exceed 15V. If the ECM thinks the FLA battery is still installed it could potentially drive system voltage too high in an attempt to accelerate charging.

But the main cause for short battery life is the battery sitting at less than a full charge, which leads to cell plate sulfation. Very short term sulfation is reversible when the battery reaches a full charge again, and even medium sulfation is reversible through a designed period of overcharging while controlling temperature, but if the battery sits on a short charge for extended periods the crystalline formation on plates permanently hardens and forever blocks future charging.

And other than a malfunctioning alternator or voltage regulator, or a parasitic drain from a malfunctioning power consumer in the car, a low battery charge is almost always the result of driving habits. BMWs use a huge amount of power, and a seldom used car, a car that experiences multiple short trips or a car that is driven slowly in stop and go traffic will not fully charge the battery. And the ECM in conjunction with the alternator can only work within the limits of engine speed and ambient temperature to optimize charging (excessive battery temperature when charging at high voltages causes water in the acid solution to be boiled away).

Batteries are not that expensive and whether you get two, three, five or seven years of life there is not a huge difference in annualized cost. For most people the annoyance of being stranded is a far bigger issue. By occasionally measuring your battery voltage after the car has gone to sleep (using a $5 multimeter) you will know if you are undercharging the battery and can expect a shortened battery life.

If driving habits lead to an undercharged battery, the best solution is a battery tender, which keeps the battery fully charged and prevents sulfation, but generally requires private garaging of the car. If you cannot conveniently use a battery tender, then after two years have your battery tested for free at an auto store every six months to get an early warning of impending failure and replace it before you are stranded.