So my brother has really wanted to move the battery in his 300SD to the trunk and we had been looking around in the yards trying to find a good cable. As you may know, many late model Mercedes and BMWs have super long positive cables running from the trunk to under the hood but we found that those were rather difficult to pull. Well put together interiors plus electric seats made it impossible to pull in the yard in a reasonable amount of time.

Fortunately we found the perfect vehicle to pull one from: Chevy Cobalt/Pontiac G5/Pursuit. Very common in the yards. They have huge, high quality (surprising) cables that stretch the length of the car and are very easy to pull. All you have to do is unbolt it at the power distribution box under the hood and remove the driver's seat and rear seat bottom. The rest is just ripping it out. Since GM interior quality, especially in the mid 2000s, is utter crap, ripping up the carpet and other panels is easy enough. Took less than 20 minutes to grab two.

The cable also has a thinner wire that plugs into a maxi fuse holder with a 50 AMP fuse. Great for a wire to an amp or something else with a similarly high draw.

Since our big local yards are Pull-A-Parts (3 in Atlanta), all battery cables, no matter the length, are $4. A 50 AMP Maxi fuse alone costs $5. Didn't measure it but it was longer than my brother's W116 300SD, so somewhere around 16 feet. I believe it is 0 gauge.

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Current: 1975 450SEL, 83 300D, 88 Yugo GVX, 90 300D OM603 swap, 91 F150 4.6 4v swap, 93 190E Sportline LE 3.0L M104 swap, 93 190E Sportline LE Megasquirt, 03 Sprinter, 06 E500 4Matic wagon.

Good info about the GM cars, didn`t know.

I have pulled 3 cables from some model BMW. don`t remember which one.
Wasn`t all that difficult as I remember. Runs through the rear bulk head, then along the
rockers on the inside behind the carpet. Held in with some plastic clips.
Then under the dash to the firewall.
Maybe 30 minutes or so.

Think it was $5 for a 12 ft piece. 10lbs of coper for $5, ain`t too bad a deal.

I used one to replace the cable on my 86 Ford 6.9 Diesel. If available from the dealer it was
about $250, did it for something like $30 with new crimped on ends.


Charlie


sent from my pos computer
she`s getting ready to crash.

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there were three HP ratings on the OM616...

1) Not much power
2) Even less power
3) Not nearly enough power!! 240D w/auto

Anyone that thinks a 240D is slow drives too fast.

80 240D Naturally Exasperated, 4-Spd 388k DD 150mph spedo 3:58 Diff

We are advised to NOT judge ALL Muslims by the actions of a few lunatics, but we are encouraged to judge ALL gun owners by the actions of a few lunatics. Funny how that works

Good tip, thanks! Any guess as to the years for the "Chevy Cobalt/Pontiac G5/Pursuit?" I'm not familiar with these models.

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"Buster" in the '95

Our all-Diesel family
1996 E300D (W210) . .338,000 miles Wife's car
2005 E320 CDI . . 113,000 miles My car
Santa Rosa population 176,762 (2022)
Total. . . . . . . . . . . . 627,762
"Oh lord won't you buy me a Mercedes Benz."
-- Janis Joplin, October 1, 1970

You can add the HHR to that list (same basic chassis). They're '2006 thru 2012(?) - whenever they went out of production. BTW - we love our HHR - great little car and pretty much bullet proof.

Jeremy - check under the hood. If you see no battery and a terminal on the LF fender for the "+" cable, you've found a donor. The HHR battery is in the rt rear next to the spare tire well so that's another thing to look for.

I hadn't thought of harvesting these for cables but it's a great idea. I bought welding cable to make mine and while it wasn't TOO pricey it was a lot more that the OP posted (I think I paid $35 for a 25' roll). I'll keep this in mind for the next time.

Dan

I have used inexpensive jumper cables as a source for large capacity wire for rear battery installation. A cable with the ends already attached though is very desirable.

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[SIGPIC] Diesel loving autocrossing grandpa Architect. 08 Dodge 3/4 ton with Cummins & six speed; I have had about 35 benzes. I have a 39 Studebaker Coupe Express pickup in which I have had installed a 617 turbo and a five speed manual.[SIGPIC]

..I also have a 427 Cobra replica with an aluminum chassis.

Cobalt is 2005-2010 IIRC

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Current: 1975 450SEL, 83 300D, 88 Yugo GVX, 90 300D OM603 swap, 91 F150 4.6 4v swap, 93 190E Sportline LE 3.0L M104 swap, 93 190E Sportline LE Megasquirt, 03 Sprinter, 06 E500 4Matic wagon.

Thanks—modern stuff! No wonder I wasn't aware of the model names.

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"Buster" in the '95

Our all-Diesel family
1996 E300D (W210) . .338,000 miles Wife's car
2005 E320 CDI . . 113,000 miles My car
Santa Rosa population 176,762 (2022)
Total. . . . . . . . . . . . 627,762
"Oh lord won't you buy me a Mercedes Benz."
-- Janis Joplin, October 1, 1970

Some pictures

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Current: 1975 450SEL, 83 300D, 88 Yugo GVX, 90 300D OM603 swap, 91 F150 4.6 4v swap, 93 190E Sportline LE 3.0L M104 swap, 93 190E Sportline LE Megasquirt, 03 Sprinter, 06 E500 4Matic wagon.

Just so the other readers know, be sure to use a large gauge ground strap between the engine and body otherwise the starter / alt will seek a ground through anything else it can find. Then tie the neg battery to the body as there is no need to run 2 cables to the front.

I know in theory you shouldn't NEED 2 cables from the rear battery but I've never had any luck running a single cable and I'm not sure why. I have have racing buddies who have fixed "issues" (slow cranking, poor charging, etc.) by running a ground cable from the battery to a starter bolt (also were I run mine).

I'd say try a single cable and a good ground as described but be prepared to add a main ground IF issues crop up. I'm sort of a freak for grounding stuff after finding that electrical issues are most often the result of poor grounds so maybe I'm just a bit hyper on this.

Dan

Saturn ions also should be similar. I had an 05 that had this setup, I believe it's based on the same cobalt frame/chassis/design.

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1982 300D (w123, "Grey Car")
1982 300D (w123, "Blue Car")
2001 Ford F150 "Clifford" (The Big Red Truck)
1997 Dodge Ram 2500 12V Cummins
1996 Dodge Ram 2500 12V Cummins
Previous Vehicles:
1995 E300D, 1980 300SD, 1992 Buick Century, 2005 Saturn Ion

Every rear battery MB I'm aware of uses the grounding system I've described.

If someone has poor charging, that is a sure sign that the engine isn't grounded with a large enough strap to the same member that the battery is grounded to or if they added such a strap, the electrical conductivity is poor due to improper instillation.

A second cable adds weight for no good reason.

Looking at a resistivity chart,

Copper 1.724 x 10-8 Ohm M

Mild steel 15 x 10-8 Ohm M

This makes steel 8.7 x less conductive than copper

But some sources show 1.67 for copper and 16.2 for steel, I'll use 10 X for a round number.


Copper 0 cable is 0.324" dia . solve for area: 3.1416 * 0.162 ^2 = area 0.0824 Sq in

For steel cable to equal the resistance of copper, the cable must be 10X area ( not diameter ) .

Solve for diameter: 0.824 Sq in / 3.1416 = 0.262 sq rt = 0.512 * 2 = 1.024" dia

I'd think there is more than enough steel in a car body or frame to equal 0.824" Sq inch / 1.024 diameter

Wow, thanks so much for the tip! I see those at the yards all the time, never realized they were hiding such a useful part.

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"Senior Luna, your sense of humor is still loco... but we love it, anyway." -rickymay ____ "Your sense of humor is still loco... " -MBeige ____ "Señor Luna, your sense of humor is quite järjetön" -Delibes

1982 300SD -- 211k, Texas car, tranny issues ____ 1979 240D 4-speed 234k -- turbo and tuned IP, third world taxi hot rod

2 Samuel 12:13: "David said to Nathan, “I have sinned against the Lord.” And Nathan said to David, “The Lord also has put away your sin; you shall not die."

I checked Windsor (California) Pick-n-Pull today; regretfully, none of those "modern" cars have graduated to this junkyard. The GM stuff seems to be mostly 1990s full-size cars.

Have 140s made it to Windsor? It's not difficult to relieve a 140 of its battery cable. Certainly no need to remove the front seats. It goes to a distribution block in the passenger footwell.

Sixto
83 300SD