Hey folks, quick question regarding batteries for my 2005 E53 3.0i. RealOEM shows part numbers for both 80ah and 90ah versions. How do I know which spec is correct for my X? I don't know what was installed in it originally from the factory unfortunately. Thanks! I'm reading it is not good to use a lower ah than what was recommended and used by the factory. There is an AutoCraft in it now that lasted 6 years but I can't find an ah spec for it. Only the CCA, which is 800. Thanks in advance-

It won't "hurt" to use a slightly lower capacity battery but you may find it will go flat on you more often (with a high accessory load).

I'm using a DIN88 battery with is rated at 860 CCA and 100AH - it's pretty much the largest battery you can fit in the space. A DIN85 battery was in there prior to this one (780 CCA 86AH) - worked fine in my 3.0d.

Just ignore realoem.com for now.
I'd recommend an Exide 94R at Home Depot for about $129.

Exide warranty is good too:
https://www.exide.com/sites/default/...arranty%29.pdf

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I would give Exide at Home depot a try except when I went to look for one several months ago I had to go to 4 diff stores and when I finally found one it had a date stamp of more than a year old. The home depot people tell me the Exide battery rack is filled directly by the Exide rep and they never know when he is coming.

Maybe it's better now.

I Like Walmart for their Ever Maxx batteries.

Re Home Depot, you can input Zip code for the stores and check to see if they have it before driving there.
Any Exide L3, L4, or L5 will work as I posted on an earlier thread.

The I6 (3.0i) uses the H7 while the V8 (4.4i/4.6iS/4.8iS) use the H8. I like the safety net of the higher Ah battery, especially when my car has been sitting quite often now - so I went with the H8. Been using the AGM H8 on my last 2 batteries and I'm happy with it.


Agreed. That was the main reason I went with the Walmart AGM on my recent replacement. We shall see if that was a good idea :p:

I have an H8 (Champion H8-900CHAGM) in my 2001 3.0i.

I had really wanted to put as big as possible in there, specifically an H9 so I'd be able to swap for debugging purposes with an H9 that my Cayenne can use. After I concluded the H9 would not fit in my X5 (I got in there and measured, looked, thought about what I could do with some Dremel tool work on the plastic, etc.), I decided on H8s for both the X5 and the Cayenne.

So I would ignore anything about CA, CCA, etc. Get an AGM of the biggest size that will fit, and for my 2001 3.0i at least, that was an H8 (that is a spec on the dimensions of the battery).

Attachment 80591

Attachment 80592

BTW, the Champion brand is made by Johnson Control (they have a new name following sale of the company a couple of years ago) and is the PepBoys store brand.

Warranty and easy use of that warranty with local store availability (e.g., vs. buying from Amazon) for a test and free swap is a big factor - so PepBoys, Home Depot, Costco, etc. are all good choices there.

I don't know who BMW uses as mfg for their battery now, but when the E53 left factory many moons ago, EXIDE was the supplier...

I really like EXIDE bc the quality is great and I can find it at Home Depot easily (search for availability first)...

The Walmart battery (Everstart ? sp) is made by Exide recently...

Here is a photo of the original BMW E53 battery, you can clearly see the word Exide on it...

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If you've got a Costco membership, their pricing and warranty for Interstate batteries is fantastic. Dead battery under warranty? Just return it and buy a new one with the refund. No hassle. No testing. Too bad that the X5 is the one oddball in the collection (aside from my truck) that doesn't take an H6.