Replacing 105AH battery

[oldskewel]

Originally Posted by Qsilver7

Based on the East Penn battery chart in post #2...their 95R battery has a length of 394mm (or 15½ inches)...so if the Bosch S5A15 is 393mm...then it would be considered a 95R/H9 battery...that's if it is sold here in the USA.

I'm about to get a battery that I'm hoping will fit in my 2001 3.0i E53.

Currently in there is an H8, wanted to see if an H9 would fit. Nothing completely conclusive found online here, so I went and took a look. Here's what I found:

The overall length (side to side) of the rectangular cavity is greater than the ~15.5" length of an H9. Maybe 1/4-1/2" to spare, total on both ends.

There may be some taper so the opening at the bottom is slightly less than this, but not much. But that does not matter because ...

The problem / issue is that on the left side of the box, in the middle (fore-aft), there is a protruding rectangle of half an inch or so, running top to bottom. And then down at the bottom, there are some fins that stick out about 3/4 inch. The fins are what the left side of the bottom of the battery butts up against, while being clamped on the right side.

My conclusion is that if I really wanted to fit an H9 in there, I could cut down those plastic fins, and that plastic protruding rectangle, and I could stuff the H9 in there. Yes, the rectangular box is overall big enough.

But thinking that it is designed to have some air gap in there, provided by the fins, etc., for convective cooling, I think I will live with an H8.

BTW, I already have a pretty new H8 in the X5, but am about to buy a battery for my Cayenne, which specs an H9, but actually has an H8 in it right now. Hoping to keep things interchangeable for debugging, I'll go ahead and buy an H8 for the Cayenne. So if I ever get a mysterious electrical issue in either car which may be battery related, I will just swap them and see what happens.