How is the dual battery setup SUPPOSED to be wired?

CamB · CamB's Garage

I had a fun weekend fixing PO bodgery and inhaling too many POR-15 fumes.

There was a little surface rust in my front pan so I cleaned it up and repainted the flat portions and battery boxes in POR-15 (which dries as hard as nails but don't get it on your hands!). Very satisfying and, as my car is black, fairly stock looking (a bit too glossy).

While the battery was out, I addressed the wiring. The car is a '69 so has dual battery boxes, but it has been "converted" to single battery.

I don't mind the single battery (which is on the passenger side), but thought you might find the wiring effort from the PO interesting.

The positive cable seems reasonably ok. The ground ran around the back of the gas tank, then back up to a grounding point under the dash. That is my question - is that a factory grounding point? If I wanted to go back to 2 batteries, what is involved (I will probably just copy Matt Smith's car - he lives close).

I pulled the whole lot out and used the "proper" factory grounding point directly above the battery - much better.

So - you might be wondering what is so incredibly bodgy about a long ground up under the dash? The bodgy part would be the conversion to one battery - the ground lead was "joined" in approximately the middle, using the highly secure crimp-it-together-side-by-side-and-get-lots-of-solder-all-over-it-and-hope-it-remains-conductive-then-wrap-it-in-lots-of-electrical-tape" technique.

Unbelievable.

Early_S_Man · 12-02-2001, 02:08 PM

Cam,

No, the factory ground is an M8 post with a wing nut ... to the rear of the box, near the fuse block.

Tyson Schmidt · 12-02-2001, 02:11 PM

Each battery has it's own grounding point. Right above it. Held on by a big wing nut for quick removal. The positive cable runs from the starter in the rear, up to the drivers side battery. The drivers side battery has a positive terminal with two cable connections. There is then simply, a positive cable running from the drivers battery positive to the passengers battery positive. It runs back behind the gas tank. If you look down at the drivers front corner of the tank, you can see the opening for the cables to run through.

RoninLB · 12-02-2001, 02:52 PM

Why would you want 2 batteries? Weight balance, back-up system, 11:1 compression, audio system???

CamB · CamB's Garage

Thanks guys.

I don't really want two batteries, except Matt will give me crap (something wishy-washy about "one of the neat things about early cars

to which I totally agree but can't be bothered dealing with).

I will have another look for the ground post on the driver's side - I didn't see it but it may have been "removed" at some stage in the past. It would be pretty easy to put it back the way it should be, but I like it how it is now. I will probably renew the cable to the starter (the one in there now has a "join" to make it long enough to reach the passenger side, which I have left well enough alone but looks like it is two ring connections joined with a bolt and wrapped in..... electrical tape).

Thanks again