Battery Relocation Wiring - with help from an e36 and e46

[Healey3000]

 

 

 

 

 

 

 

 

 

Edited June 8, 2018 by Healey3000

[gambitpaul]

That is great. Very professional write up also. I want to do the same thing.

Would you add some details about the battery mounting and negative cable, maybe a few pictures of that area. Did you buy the e46 cable and e36 box new? If so you have part numbers. About how much was this whole modification.

 

Again, great write up and pictures.

Thanks,

Paul

[Jjmoonen]

Well done on all points! I love this and have been looking at relocation options myself. I am curious what size battery you used and how much space/clearance you had under the seat?

[Healey3000]

Thank you both!

 

I've updated the images to add details on battery mounting and grounding.  I made an error in the original post - the battery is an ETX-30, not an ETX-18.  I've fixed that.

 

As for clearance, this battery is almost flush with the top of the bulkhead.  This may be a problem if you plan on using the stock seat, but look at Deka's offerings and you'll see some more compact options that may be a better fit.  The hold-down is a universal adjustable width battery bar, secured to the floor by two long screws.  I had to reluctantly drill a couple of holes in the pan.

 

I hope you find this useful.  I can also add the CAD file for the mounting plate if there is interest.

[Jjmoonen]

Dude, again.......this is fantastic. While there is tons of useful information on this forum, rarely do you find it this well put together. ?

[jp5Touring]

Very nice mod,well thought out

[theNomad]

Its fairly involved to pull the e36 battery cable at the junkyard. I'd do it but need to set aside some time. So many things need to come out. Where is the junction box you used located on the e36 or 46?

[Healey3000]

3 minutes ago, theNomad said:

Its fairly involved to pull the e36 battery cable at the junkyard. I'd do it but need to set aside some time. So many things need to come out. Where is the junction box you used located on the e36 or 46?

Hi,

 

The cable is from an e46.  I'm not certain but I think I recall the e36 cable as being stiff as a rod.  It will probably be a beast to try and snake through the bends that are required.  The e46 cable is not too difficult to remove but the passenger seat will have to come out.  The rest is easy enough.

 

The e36 junction box is very conveniently located; right side near the DME box.  Simple to remove.

[Jjmoonen]

Aside from cost, any reason to not just purchase new cable?

[Healey3000]

47 minutes ago, Jjmoonen said:

Aside from cost, any reason to not just purchase new cable?

No, just cost.  Actually, the quality of the BMW cable is pretty impressive, based on what I've seen of other cables.  You also get an eyelet on one end and if you want to use a battery with conventional posts, the other end is ready too.  If you plan on putting the battery in the trunk, I don't think the e46 cable will be long enough.  Try an e39 for that as it's a bit longer and the exact same raw cable stock.

 

If you do buy cable to make your own with, I highly recommend laying hands on it and getting a feel for the flexibility.  Welding cable would be best.

[Jjmoonen]

Good to know. I guess I'm accustomed to the "meh" quality of older domestic vehicle battery cables. I have used welding cable in the past though and that is nice stuff, or a fine strand Marine rated cable too.

[bianchini]

definitely adding this to my list of "to-do" for my 74!

 

Thanks for the write up. 

[johnny02]

Thank you. This is a really great, concise writeup.  

[uai]

I use a "classic" approach for the Jump starter Connector.

Just take a very long nut and mount the cable eyelet directly to the starter. A short piece of rubber tube protects it from being touched while wrenching in that area.

 

[John_in_VA]

6 hours ago, uai said:

Just take a very long nut and mount the cable eyelet directly to the starter.

 

Can you provide a photo?  I can't imagine a long nut.