Battery Relocation

[GregWeld]

I see this mistake time and again -- and it really just shows a lack of electrical knowledge...

There is NO REASON to run a GROUND cable "forward". Just run the ground cable to the nearest convenient point on the chassis or body. Then be sure to run a separate ground strap from the body/chassis to the engine block (the largest amp draw when cranking).

GOOD solid grounding is just as critical to the electrical system as the Positive side. Remember electric is a CIRCUIT...

If you ground thru paint - on your smaller connections... be sure to use a STAR WASHER UNDER the connection. These are designed to cut through the paint and dig into the metal. Don't use a split washer which was designed for a completely different use.

Running the positive through body cavities --- is just a fire waiting to happen... if you do this -- be double triple sure you've protected the cable from chafe (remember you can no longer see it and check it!)... and that you've put some kind of retention every 6". You'd be surprised how much vibration is in a car going down the road!

[RdHuggr68]

I have the factory ground from the block to the frame, it seems kind of small, what size would you recommend?

[GregWeld]

Something that is capable of carrying 200 amps!

Like battery cable... only don't use some cheap junk from Target... I prefer welding cable -- super fine strands of copper... 1/0 or 2/0 would do the job.

[ErikLS2]

Current (amps) is the same throughout the entire circuit, meaning both the ground and positive cables need to be the same size (if they're the same length) for it to be right.

[72Z/28]

Originally Posted by ErikLS2

Current (amps) is the same throughout the entire circuit, meaning both the ground and positive cables need to be the same size (if they're the same length) for it to be right.

I am using #1 cables and the negative is bolted to trunk sheet metal. Is it OK to use 1/0 ground strap between the body and engine and another strap between engine to frame?

[ErikLS2]

With short run lengths like that on the ground side, you can run a much thinner cable than 1/0, like 4 or even 8 ga. It can be mathematically calculated but I can't tell you the formula off the top of my head. A thicker cable wont hurt you though except for the added weight. Do a voltage drop test on both the ground and positive cables with the engine cranking. To do that, measure with a volt meter from the positive battery terminal to the positive terminal on the starter. Then also from the negative terminal on the battery to the engine block. If you get a reading more than 0.1-0.2 volts, the wire is either too thin or the connections are dirty, have paint on them, etc. The idea is to have as thin a wire as you can without any voltage drop, with maybe 1 wire gauge thicker for comfort. Since the most current is flowing when the engine is cranking, that's when you want to do this test and the test will only work when current is actually flowing. Here's a handy little chart I found when Google-ing wire sizes too:

[jarhead]

good information

[MaxHarvard]

Originally Posted by GregWeld

I see this mistake time and again -- and it really just shows a lack of electrical knowledge...

There is NO REASON to run a GROUND cable "forward". Just run the ground cable to the nearest convenient point on the chassis or body. Then be sure to run a separate ground strap from the body/chassis to the engine block (the largest amp draw when cranking).

GOOD solid grounding is just as critical to the electrical system as the Positive side. Remember electric is a CIRCUIT...

If you ground thru paint - on your smaller connections... be sure to use a STAR WASHER UNDER the connection. These are designed to cut through the paint and dig into the metal. Don't use a split washer which was designed for a completely different use.

Running the positive through body cavities --- is just a fire waiting to happen... if you do this -- be double triple sure you've protected the cable from chafe (remember you can no longer see it and check it!)... and that you've put some kind of retention every 6". You'd be surprised how much vibration is in a car going down the road!

Mine is routed to the roll bar and is only about 24" long. Works like a charm.