PepBoys sometimes has deals where you can get both the 25% off (e.g., off $195) and also get a $40 rebate. Over black friday weekend they upped those to 35% off and a $50 rebate (they also rebate the tax, so it's closer to $55 coming back in my case). I think net was under $85 each on the two Champion (made by Johnson Controls) AGM batteries I got there a few weeks ago.

I actually needed one of the two, but when I confirmed how good a deal it was, I bought the second one, perhaps a year before I actually would have needed it. Could not afford not to buy it at that price.

BTW, I got the H8, but H9 (similar dimensions, but ~1.5" longer, and accordingly increased capacity) was the same price. Looking into it carefully, an H9 would not have fit in my 2001 3.0i without elective surgery on the battery box. I think I posted details about those findings in one of the major battery threads on this forum. I now have identical Champion H8 AGM batteries in my E53 and my Cayenne. The Cayenne fits an H9, but I wanted to keep them the same size so I can swap them as an easy debugging procedure for those weird intermittent electrical problems that can happen.

Can verify this...the e53 X5's battery location is not long enough to accept the H9/95R battery's extra length. The e53's generational cousins (e38/e39) though...can mount either the H8 or H9 battery size...as well as the later generation X5s (e70 & f15 & g05). But the e53 X5s battery box doesn't have enough room to accept the H9.

The left side of the battery box (the side where the vent hose connects) has raised ridges on the bottom of the box that are there to prevent the battery from moving sideways and crushing the vent hose...and the right side of the battery box is where the battery hold down clamp is secured to prevent the battery from moving up/down as well as side to side. So the extra length of the 95R/H9 battery prevents it from fitting correctly in the battery box. But the 49/H8 or 94R/H7 battery will fit:

^^^ :thumbup:

Yes, exactly as I found. Good pics.

The overall dimensions of the rectangular box / opening there will fit an H9, but would require cutting all those plastic things that protrude into that volume, not being able to clamp it down, etc.

I had really hoped an H9 would fit so I could run with a pair of H9s in my Cayenne and E53, but H8s are doing fine.

H8 fits without modification? I was concerned that the vent wouldn’t line up.


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It's a flexible hose - why would it not line up? :confused:

Re. the vents - when changing my battery yesterday I noticed my battery clamp is corroded by battery acid and that the old and new batteries have a vent hole at each end. The new battery came with a small plug on one vent hole (the positive) so I've installed the plug on the battery negative end and the vent hose on the positive end.

Anyone else had a battery with a vent on the negative end? :dunno:

My E53 and E46 AGM batteries both have vent holes on both sides. My accessory kits came with a 90 degree connector and a plug. I connect my hose to the 90 degree on the correct side and install the plug on the other side. :dunno:

Thanks OB - that's what I figured - I think the previous owner (or mechanic etc.) failed to block the un-used vent port, leading to the minor acid damage.

Just can't get good help these days... ;)

When I installed my battery there was not much leeway on the vent hose. If the vent was on the opposite corner no chance it would reach.

Still unclear which battery might fit without cutting plastic.


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The H8 will fit without cutting. See pictures posted by "Qsilver7" - that's an H8 in there.

Yes, repeating, I dropped an H8 in my 2001 3.0i with no modifications at all needed. Clamp was a perfect fit, holding the base up against the protruding fins on the left side of the bottom of the box. Vent connected just like the one I replaced.

Here's the exact one I put in:
https://www.pepboys.com/champion-agm...roduct/2071679
BTW, from what I can tell, these Champion branded batteries are made by Johnson Controls and are only sold at PepBoys, so it's some special store-brand type of thing. 4 year full replacement warranty. And BTW, if anyone goes searching on PepBoys for other batteries, don't even try. Searching via google aimed at pepboys.com will actually get you useful info.

Most AGM batteries I've seen lately have the small standard hole for a vent plug on both left and right ends. When you get the battery at the store, it often has a rectangular, red/orange, mini-table-looking thing that plugs in and sits over the positive terminal. That piece of plastic will have a break-off plug cast into it. So that's where they give you the plug for the unused opening. Easy to miss that and mistakenly leave the second opening un-plugged.

I have also found that a plastic cap to a Presta valve (for high pressure bicycle tires) is an excellent substitute for a missing plug.