Battery to bed relocation

407 Views 9 Replies 8 Participants Last post by cliffpoint, 9 d ago

98K350012VDually

Discussion Starter · 17 d ago

Hey, so I have a 94 Cummins with two 34 group size batteries I'd like to relocate to under my bed on the passenger side. Itll be 10-15 ft of wire so according to the attached page I should be running 2 awg wire because my alternator only puts out 135 amps.
Now my question is what the effect will be on the wires when I fire my starter because that thing draws, what, 500-700 amps? Will that be enough to burn up my 2 awg wire? Should I run 2 separate circuits?

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Redark1

· #2 · 17 d ago

My 2 cents is get double 00 gage wire. Get that and do it once and be done.

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char1355

· #3 · 17 d ago

I recommend 2/0 gauge wire on all diesel applications like Redark1 said. That is not 2 gauge but is 4 times bigger. The charge wire front the alternator does not need to be that big but the cable going to the starter is where you need big current capability. There is usually a fusible link in the charge wire circuit which is 4 gauges smaller than the wire. Don't forget that your ground cable should be the same size.

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Blackduck596

· #4 · 16 d ago

From the Cummins manual. Minimum of 00 for battery cable and preferably the ground attached to a starter motor retaining bolt.
You would need that #2 cable for the alternator charge cable, alternator to the battery.

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dreamin

· #5 · 16 d ago

As Blackduck said ground to the motor. I see this mistake all the time. You ground the frame off the motor. Do not ground the battery to frame and then ground frame to motor. Some people think it’s the same. It doesn’t matter if all the cables are big. It’s not the same.

The reason why is a failure of the motor to frame cable. In one case, the motor starts and you wonder why some things don’t work right. (Lights, instruments and radio) In the second case, when you hit the starter, you will fry all other paths to ground from motor to frame. I’ve seen a throttle cable melt.

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eggman918

· #6 · 16 d ago

dreamin said:
As Blackduck said ground to the motor. I see this mistake all the time. You ground the frame off the motor. Do not ground the battery to frame and then ground frame to motor. Some people think it’s the same. It doesn’t matter if all the cables are big. It’s not the same.

The reason why is a failure of the motor to frame cable. In one case, the motor starts and you wonder why some things don’t work right. (Lights, instruments and radio) In the second case, when you hit the starter, you will fry all other paths to ground from motor to frame. I’ve seen a throttle cable melt.

When I was a Kid I had that issue and along with every little ground wire it melted he copper oil pressure gauge line right at the gauge spraying my legs and feet with engine oil.... Fun Fun Fun

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ntsqd

· #7 · 9 d ago

2/0 welding cable is what I used, and I left the batteries in the stock locations on our '96. For that length of cable run I'd be looking at either 3/0 or 4/0 for the starting cables, and #4 wire for the alternator to starter charging wire.

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cliffpoint

· #8 · 9 d ago

All the big old Delco Remy starters had the positive and negative posts. The negative post was grounded to the starter negative post, then another cable to the block,
then another cable back to the frame, then ground straps to the body.

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