battery in trunk

[Highbanked Hauler]

 When you put a battery in the trunk you obviously run the positive cable to the starter. What about the negative cable,can it be anchored to the body or does it have grounded to the motor ??

[macca3441]

You can connect your negative to a body earth (just make sure its a nice, clean, tight connection), then use another battery cable to earth between the body and engine block!
Make sure all connections are clean and tight, and that you've used good quality battery cables!
I prefer to use 0B&S, or 00B&S cable.

Wade

[FLG]

You can connect your negative to a body earth (just make sure its a nice, clean, tight connection), then use another battery cable to earth between the body and engine block!
Make sure all connections are clean and tight, and that you've used good quality battery cables!
I prefer to use 0B&S, or 00B&S cable.

Wade

Yep. Thats how its done with factory trunk mounted batteries.

[Chryco Psycho]

I have often run the negative cable back to the rear of the trans to make sure it grounds properly

[Highbanked Hauler]

I have often run the negative cable back to the rear of the trans to make sure it grounds properly

  I was wondering because of the little cable that grounds the motor to the firewall 

[Ghoste]

I have only moved it to the trunk on two cars but in both of those cases I grounded the battery to the trunk floor and the engine to the firewall as normal.

[Paul G]

My only concern is these unibody cars are welded together. Not intended for the body to carry high current. Newer cars with battery in the trunk are designed for it. I would do like Neal said and run the neg cable to the engine block or trans. If it was me. 

[FLG]

My only concern is these unibody cars are welded together. Not intended for the body to carry high current. Newer cars with battery in the trunk are designed for it. I would do like Neal said and run the neg cable to the engine block or trans. If it was me. 

Not true, a lot of newer cars are unibody..if not mostly all.

My 87 BMW has a little piece in the trunk welded to the quarter panel and battery is grounded on there, but is VERY important to make sure your engine ground is good.

[macca3441]

I have often run the negative cable back to the rear of the trans to make sure it grounds properly

  I was wondering because of the little cable that grounds the motor to the firewall 

Please re-read my first response!!
Wade

[A383Wing]

that little cable from motor to firewall is not large enough to carry starter current

Bryan

[FLG]

that little cable from motor to firewall is not large enough to carry starter current

Bryan

Agreed (not to mention its 40 years old), hence as macca said..you need to run a higher diameter cable from engine to the body.

[Ghoste]

A larger cable for a ground is a good thing to do.  I run a larger and a couple of extra ones on my car as it is.  I also wouldn't be concerned about the current in a unibody.  It will be just fine.