Yep, good move, you certainly don't want Joe Hundai to bust your air suspension hoses. A $90 install could quickly turn into a $1000 repair.

I bought the same battery from Sam's about 3 years ago and I haven't had any problems.

I checked my local Sam's yesterday and they do not stock the Energizer E49 battery. I guess it depends on where you live. My battery is 6.5 years old with 25k on the odometer and it's still going strong so I'm not in a rush to replace it.

My local sams club no longer carry the energizer. They switched to a different brand.

Mine carries mostly Interstate batteries. They didn't have a 49-sized model though.

This is the recommended Interstate on their site ($193 suggested retail, 720 CCA):


http://www.interstatebatteries.com/cs_eStore/Search.aspx/Automotive-Truck/BMW/X5?dsNavigation=Ns~product+Type|101|1|,N~21-4294493536-4294493492-2147384818-4294493514

Does anybody know the AH (Amp Hours) and RC (Reserve Capacity) rating of the stock battery (I'd be interested in the 4.4l; not sure if there would be a difference between its and the 3.0's)? I've been searching, and I can't find it. Is it stamped somewhere on the battery?

I called Everstart, and the guy told me he's pretty sure the RC on their MAXX-49 is 140, and he thought the AH was between 70 and 80, but he was going from memory, as he didn't have access to a spec sheet. The RC on a Duralast 49-DL is 155, but its AH wasn't listed. Thanks.

If your OEM battery is 640cca the AH is 80, if it is 720cca the AH is 90.

Thanks for the quick reply. Any idea what the reserve capacity is? And in terms of compatibility with the car's electrical system, which is the more important factor? Thanks.

Don't remember the RC off hand unfortunately... They are both important in their own right. All the info on what means what can be found here. But basically AH and RC have to do with the output capacity of the battery other than starting (which is all CA and CCA is, just for starting) and how long it takes to drain with a load/draw on it etc.

That's a very informative link. Thanks.