318ic - moving battery to trunk - ?'s

[Cobra Jet]

Just curious if anyone has moved the battery from the engine compartment in their 318ic to the passenger side trunk area?

If this has been done (or can be done), are there any links and what parts are needed to do such a swap?

How come when the convertibles were built at the factory, the battery was not located in the trunk like on the coupes & sedans?  Was this a weight distribution issue?

[tony92ic]

I don't think it's weight distribution, because if you pull off the trim panels of the convertible you'll find a big 40# (I am guessing) steel weight under it. I assume to balance the car because they didn't put the battery back there.

You would assume that you could simply get the battery cable from a tin top and install it in the cabrio, but maybe there is a reason besides cost that BMW didn't do it.

I bought an Oddessey dry cell. One of those small motorcycle battery sized ones and put it where the big battery sits now. It weighs probably all of 5 lbs. So it redistributes the weight and cuts overall weight at the same time. And I didn't have to try to run a giant battery cable the length of the car. You do have to fab a hold down strap though.

I haven't had a problem with it, but I don't drive the cabrio in the winter so Cold Cranking Amps aren't a problem. If its a winter driven (and i mean someplace that has a winter) car I am not sure the CCA rating is high enough. If you live in a place where 40f is cold it'll work fine.

[D. Clay]

I would get a cable at the junk yard. You could also see if there were any other changes necessary. That weight in the trunk of the cabrio is supposed to offset chassis flex and what the the English call scuttle shake. The parts manual calls it a vibration damper. Check the price of that chunk.
http://www.realoem.com/bmw/partgrp.do?model=BB13&mospid=47326&hg=51&fg=80

[bmwpower]

It's definitely for balance.  If you're in the driver's seat and the battery is up front, even with the 40lb. weight (never seen one, but don't dispute it) the car will be more neutral.  Especially in an M42.

[tony92ic]

Mine's keeping my garage floor from vibrating.

I took it out figuring whatever it did for weight balance had to be offset by lugging around all that extra weight especially in an M42 powered car.

Maybe I'll sell it on ebay as an ultra rare BMW OEM chassis tuning upgrade. (Probably M designed since its priced like an M3 part.) It was only available on the cabrios, you gotta have one for your coupe or sedan. $600 from BMW  - "Buy it Now" only $499.

E36 guys have their cross braces we have our Vibration Dampner/ cross weight balancer. Won't they be so jealous. Pretty soon they'll all be bolting cement blocks in their trunks to try to keep up.