Went to autozone today.. Told them my car then showed them the specs I wanted.. They only had h8... So I said pull that one with the 5 year warranty.. It comes out and is about 18 inches long!! So that sucked, then asked them which ones where vented.. They had no idea. Sooo this is kinda why I've been asking for specific batteries, I figured this would happen.

An 18" battery (if that's actual length of the ???H8 battery they brought out)...would fit. BTW, which H8 battery did they pull? The Duralast H8 Gold (which is a lead-acid battery), or the Duralast H8 Platinum (which is an AGM battery)? Or did they pull Duralast 95R or H9 battery? Those tend to be the longest.

The 49/H8 & 95/H9 batteries are what I normally recommend because of not only their height & length, but their other specs are usually the same or better than the original battery:

• RC - reserve capacity (usually 100 min +)
• CA - cranking amps (usually 850+)
• CCA - cold cranking ams (usually 850+)
• Ah - amp hour (usually 80, 90, or 100 Ah)

If the aforementioned battery sizes aren't available for some reason, you could also look for a 47/48/H6 or 93/94/H7 class size battery. Their specs my be slightly lower than the 49/H8/95/H9 and may only have 70 or 80 amp hours.

You really don't require more info or a "specific" battery because ALL 49/H8 or 95/H9 batteries will fit. Its an industry standard...these are the size batteries that will fit in your battery compartment. The compartment has multiple hold down points to accommodate various length batteries.

If you look to the right of the long bolt that secures the hold down clamp, you'll see approx 2 or 3 additional threaded holes on the bottom of the compartment:

As far as venting...not sure why no one at a battery store knew this infomation. Batteries either vent from the side or the top center. If the design of the battery vents from the top center, then you'll need the vent kit to extend over to the side of the battery. If the battery vents from the side, then just use the little elbow that came originally with your BMW.

Since not all cars require battery venting...the side vented batteries are usually sealed over with a thin piece of plastic, and you just pierce thru it when you hook up the little elbow. You can see the little round hole on the side of this EvertStart Maxx battery below (Walmart):


If the battery vents from the top...it will be designed like in the illustration below and the pic of the Interstate MTP-93 battery...and the vent hole is just above the word PROPOSITION on the Duralast 49 DL:

Hahahaha ok maybe not 18 but it looked really long compared to the BMW battery currently in there.. It was duralast platinum.. H8 so I guess I'll go back because it'll fit?

Ah...thats their AGM battery...specs should be around 13"-14" in length....and I think it vents on the side...so make sure not to lose your elbow (if you still have your orig battery) that connects the vehicles vent tube to the battery's vent hole. :)

BTW, when I look up the BMW battery for my 06 X5 4.4 (BMW part # 61217586962)...it is an Exide battery listed as a 90 Ah battery with only 720 CCA...and an MSRP of $169.61.

Here's the specs from AZ's website of compatible H8 batteries they sell for the e53 X5...prices are set locally, so some prices may be higher or lower than what I have listed... (click links for more details):

I suspect since I am following this thread and I can't remember when I last replaced my battery I will be doing so soon.

I have to duct tape my keys to my ear so I least I find them the next time I look in the mirror so I don't recall having any success purchasing a battery without having the old one there for comparison. That's one reason why I take it in with me. The other is so I can get it load tested before replacing it. If I recall correctly it wasn't always the battery. When I finally find my favorite auto parts store I usually leave with what I need.

Yeah I replaced mine a few weeks ago too. Autozoned it with the biggest duralast they had. 7 year warranty, free replacement first 3 years. I LOVE getting to the battery in 29 degree weather. LOL. But, its good to go for hopefully many more years! 187,000.