Major battery manufacturers/retailers often have battery selection dialogues that will take your vehicle description and return the proper battery.

Yes, I believe that some modules will flake-out, that's why BMW says NOT to disconnect the battery for troubleshooting charging issues, the evidence that the modules might retain will be lost.

It is the Twenty-first Century, not much is as it was.

Yes, take a picture of it and post it.

It should look like this: black case with a BMW sticker. The most important parameter of the battery that you should match is the Amp Hour (Ah) rating. It should be about 90Ah.

Problem is that most, if not all batteries that you can find in the retail stores, do not list the Ah number. Only if you have the store manager call the manufacturer, can they sometimes provide you with the Ah number.

You can calculate an approximate Ah number based off of the Reserve Capacity rating:

Amp/Hours = (Reserve Capacity / 2) plus 16.

But this is ONLY an approximation. If you want something more precise, you have to use Peukert's law (https://en.wikipedia.org/wiki/Peukert%27s_law).

If you used the above rule on the RC rating of the battery in the picture below, you'd get 96Ah, yet the label says it is 90Ah ...

After you install your new battery and register it, the alternator is programmed to charge the battery at the Ah capacity of the old battery.

If you install a battery with higher Ah rating, you need to code (program) the car and tell it that you have a battery of higher Ah rating. e70 X5's build prior to 10/2011 have the following set points only:

KLASSE_BATTERIE:
46ah
55ah
70ah
80ah
90ah
110ah
40ah_agm
60ah_agm
70ah_agm
80ah_agm
90ah_agm

In other words, you cannot install a battery with an Ah rating grater than 90. If you do, the battery will be constantly undercharged, and you'll compain that you have a "bad" battery ...

GL

thanks! those sites said the AGM but I wanted to make sure

ugh about the modules and how annoying tech can be sometimes (and amazing/great all the other times hehe)




understood thanks, I took a picture but it turns out the label matches 100% with the pic you attached to your post

checking PN 61217551331 it appears it's the AGM battery, 90ah... don't know why I didn't think of searching the PN yesterday but thanks very much for your help

No need to buy BMW OE.

Let us know what equivalent you get. Be of interest for the next victim.

I replaced my E90 335i battery with the same CCA and such from Interstate Battery. No coding or anything and it was all fine for about a month i drove. Car was in at an indy shop for service and asked the tech to program it, he tried and it didnt work for some reason but he did say as long as its the same or better than OEM it will be fine, he said he never codes his new batteries. This is a very known local European car shop, so i left it uncoded and nothing happened.

I also replaced the battery in my E90 335i w same one from the dealer myself with no coding, it's been 4 years already...no issues.

Price shopping:

Looks like Walmart would be the best deal (cheapest + longest warranty if you count the prorated 24 months as well) if it was stocked anywhere, but the AH is unknown. Of the known AH batteries the Duracell from Batteries Plus may be the best for me since it has an extra year warranty for $7 more than Autozone, will the 92ah vs stock 90ah matter?



Known AH batteries:

Batteries Plus Duracell Ultra battery - 92AH, $196 after tax and core refund using coupon CDP10011, 48 month warranty = https://www.batteriesplus.com/productdetails/sli49agm

Autozone Duralast battery - 92AH, $189 after tax and core refund, 36 month warranty = Duralast Platinum/Battery H8-AGM - Read 6 Reviews on Duralast Platinum #H8-AGM

BMW East Penn battery - 90AH, $193-257 before tax depending on battery amperage (quick price quote from friend at dealer before I knew 90AH), unknown warranty


Unknown AH batteries:

Walmart EverStart battery - unknown AH, $150 after tax and after unknown core charge, 36 month warranty + 24 month proration = EverStart Platinum AGM Battery, Group Size H8 - Walmart.com (unfortunately it does not appear to be in stock anywhere)

Pep Boys Bosch battery - unknown AH, $189 after tax and core refund using coupon ALLTIME20, 48 month warranty = http://www.pepboys.com/product/details/838838/446/

Advanced Auto Autocraft battery - unknown AH, $200 after tax and core charge using coupon L52, 36 month warranty = AutoCraft Platinum AGM Battery, Group Size H8, 900 CCA H8-AGM: Advance Auto Parts

Napa Legend Premium battery - unknown AH, $214 after tax and core charge, 24 month warranty = NAPA AUTO PARTS

Interstate - unknown AH, $249 before tax, 30 month warranty = local dealers only

East Penn - unknown AH, unknown price and not any local dealers, unknown warranty

You cannot replace a (modern) BMW battery based on CCA rating ... PERIOD.

(Well, you can, but you will run into problems later, if the Ah don't match)

No, 90Ah vs 92Ah is does not matter. Either will work. Don't go higher than 5% from stock, i.e. 94Ah to 95Ah (although I don't think they are available).

Buy the one with the longest warranty for the best price. And remember that it also needs to have an external vent!

It's hilarious that battery manufacturers will not disclose an important parameter like Ah. How deep did you dig to try and get an answer?

thanks! I'll prob go with the batteries plus one then

I didn't dig very hard as I didn't even bother to call or stop by any place, I only listed info that was readily available and found online in the links I provided