Battery relocation - ground question

[Jim64]

I relocated my battery to the trunk several years ago. (1964 Barracuda)
On Friday as I was leaving for a car show, as I was trying to start it to leave the driveway, I heard a click and then nothing. No power to my volt meter, no starting, etc.

After about 3 hours, I tracked it down to the connection between the negative battery cable and the body. The connection was tight, but apparently not a great ground, since tugging on the cable moved it enough to resolve the issue!

The 3/8" bolt goes through the sheet metal floor of the trunk, through the bracket that holds the ford-style solenoid, and then the cable terminal.

I've removed all of it, sanded down all the connection points, and I am ready to re-assemble.

I bought this stuff: https://www.amazon.com/gp/product/B0CRYCXK2Z/?tag=fabo03-20
...a conductive silicone grease. I'm thinking I can put some of that stuff between every metal-to-metal junction to make sure I never lose that ground connection again.

Is there any reason NOT to use such a product to ensure connectivity?

 

[toolmanmike]

As long as it conducts electricity as and prevents corrosion you are good. I would use a washer or two to give it some bite.

 

[RustyRatRod]

I don't think I'd put anything on the connection. Just clean the paint down to bare metal, tighten the connection GOOD. I would however, paint over it with some type of rust proofing paint. Several coats.

 

[crackedback]

How is the engine grounded to the chassis? A cable from block to frame rail is really good idea.

I like to weld a nut to the frame rail and attach the ground. You could weld a nut to the floorpan if you like. Welded in frame connected cars are much better about ground path to the front.

 

[Syleng1]

I know people don’t care for the extra weight but a ground from the battery directly to the engine is best. You’re basically running amperage thru 50 year old spot welds. I know- “everyone does it.” But with electrical… “home runs” are best.

 

[67Dart273]

Using the body for a ground is fine on older cars and was done for years. BUT BE SURE it is actually a good connection and BE SURE you have at least on, better two, large gauge (same as battery cable) grounds from block to body

BUT Modern electronics, stereos, etc, and EFI you really REALLY should run a dedicated cable from battery NEG to engine block.

 

[413]

When the battery is underhood the negative cable goes to the engine block. The ground strap to the body is like 10 gauge and runs the accessories and lights.

When battery is in the trunk you NEED a large ground cable between the block and the body to run the starter. You don't have the battery cable to the engine block in this scenario. For the starter to operate you need both positive and negative to flow the same amperage.


I would use the grease you bough and a star washer on both sides of the connection to the body.

 

[Bewy]

I would use the s/s star washer in post #2 between the lug & body metal. Nothing else. Sounds like the failure came from a loose connection.

 

[Demonracer]

Some of the lugs on the ground cables are cadmium plated, which means that there are dissimilar metals and the "will" be corrosion. My bracket car has a no oxidizing compound on each and every ground connection. When we wired my car, we put ground connections in multiple places and once done we ohmed them out to make "sure" we were grounded. I for one don't need to not make a call to the line because of something as simple as a ground connection.