Battery relocation for early E34

[Coyote_ar]

Hi guys, so my 88 525i is one of the early cars which still has the battery up front near the engine. Not the best location tbh, really in the way when you want to check your spark plugs and work on the distributor.

Since it already has the battery tray under the seat (go figure why they would bother making that tray, then putting anotherone up front ...), i was thinking on relocating it back there.

I know the basics of the circuit, but i wanted to know, where does the OEM cable go through on the more modern cars? Does it go through the hole in the firewall and under the carpet, or it goes on the outside and then gets in under the seat?

Thanks

[shogun]

I only know it from my E32, but on the E34 it is probably the same. Battery is on right side in driving direction under rear seat, from there it goes outside into a cable channel under the doors to the front, when you pull the carpet a bit you can see it.
Here pics from a 750iL when we removed a wire looms, the cables run behind the white plastic cover under the doors http://www.bimmerboard.com/forums/posts/270025/

[Jazz_89]

You should be careful. Check whether any fuel lines pass near the location you want to place the battery. Perhaps you also have to take the different voltage drop into account, due to the increased cable length. Last but not least, I think that the battery needs to be properly grounded and there must be room for battery gases to escape, in order to avoi build-up of pressure.

[Coyote_ar]

The battery holder is already there, as shogun mentioned thats the stock position for most E32/E34. Ok so the cable runs on the inside until it reaches the hole for the ECU cabling.

Fuel lines run on the other side, the left side. So that should be fine, specially if cables run on the inside. Voltage drop for such a thick cable shouldnt be a problem, but getting a proper ground if there isnt already a good place to connect to the chasis would require at least some grinding and welding.

i will remove the seat and check what i got there.