Best place for battery ground in trunk

[70spider]

Hello,
Well I am finishing up some projects on Pesto and one is to move the battery to the trunk. I was wonder for those with the battery in the trunk from the factory could you show me some pics as to the location of the battery ground?
Thanks.

[TX82FIAT]

Not at home right now so not pics. There are two locations in trunk. The more common center of the trunk wall behind the back seat. The ground at that location is within the battery box bolted to the frame. It is a really good idea to clean up the contacts and even replace the grounding wire. The second location for the 83 and up cars is behind the passenger side wheel well. Again, The grounding bolt is at the side of the battery storage shelf. I don't think either of these is better from an electrical standpoint. The weight distribution of the battery and the exhaust on the right side might help offset the weight of the driver when solo. The point is you can put the battery just about anyplace out of the way as long as it is sheltered and has a good frame grounding point.

[DRUMMOND]

Battery Ground wire is bolted to the righthand side of the battery holder frame

[70spider]

Thanks for the pic, the battery holder looks very similar to the one I plan on using. So, grounding the negative terminal to the holder frame works. Another question; I thought of running the positive cable inside the car along the passenger side tub rail then through the fire wall to a junction terminal. From the junction terminal the starter cable and alternator wire will be joined. Does this seem like a reasonable plan/route?

[DieselSpider]

Thanks for the pic, the battery holder looks very similar to the one I plan on using. So, grounding the negative terminal to the holder frame works. Another question; I thought of running the positive cable inside the car along the passenger side tub rail then through the fire wall to a junction terminal. From the junction terminal the starter cable and alternator wire will be joined. Does this seem like a reasonable plan/route?

On my 78 the factory run is similar but on the left side of the car.

[baltobernie]

The "firewall" between the trunk and passenger compartment is very robust. I welded my battery bracket directly to it, and have had no issues. Ditto the ground terminal. I'm using a size 34 battery, which fits the common aftermarket holders, but is a little shorter. I then have a little more clearance of the floor boards.



On the plus side (pun intended ), I have a race-car disconnect, which is handy for anti-theft as well as winterizing. The key is removable in the OFF position. The pigtail shown in this photo is "upstream" of the switch, and accommodates the float charger.



I too ran my battery cable along the frame rail. This BMW junction box makes for a tidy installation in the engine compartment, as well as a handy source of 12VDC for your timing light or jumper cables. Marine supply and DIY electric vehicle supply houses are good sources for quality cable and terminals.

[70spider]

baltobernie,
Thanks for the pics, Nice looking install. I really like the junction box you used, do you know the part number? Also, nice race switch a good idea.

[baltobernie]

Part #: 12-42-1-433-232-BOE (base)
Part #: 12-42-1-730-712-M9 (cover)

I'm sure there are other solutions, but I saw this on a friend's Z3

[RRoller123]

That is a really nice setup. Fantastic!