Battery Cable routing on an EM

[rbray]

It's time for me to run the battery cable on my EM. My battery is mounted behind the wheel well on the passengers side.
How have you guys with EM's routed your battery cables?
Thanks,
Roger

[larryar]

If you send me your email address, I will send you pictures of how my local EM builder routes the battery cable. My address is
lmrusso@us.ibm.com

[Dan Heck]

On a related subject, some car builders who mount the battery in the trunk in a system employing a Ford-type starter solenoid choose to mount the solenoid in the trunk close to the battery rather than in the engine compartment. This avoids running a long, heavy hot-all-the-time copper cable the length of the car. This approach might give a small safety advantage in some configurations in which that high amp cable is running close to the fuel line and assorted rotating drivetrain parts that could tear things up if they let go. The cable running forward to the starter will only be hot during the startup. A trunk-mounted solenoid needs to be enclosed in a simple box to prevent the possibility of sparks touching off any fuel vapors or battery-generated hydrogen in the trunk.

Dan

[rbray]

Thanks for all the information guys.
Roger

[Chuck Hurley]

Use 1/0 automotive type wire Power Path
#736121 by Cooper Automotive - 25' roll

Use grommets wherever you pass through the body.

Run the wire on the opposite side of the car from the fuel and brake lines and on the inside of the frame. Clamp at intervals that allow for little slack with adel clamps
which are rubber coated (available at West Marine on-line) with stainless steel construction. Tap the frame for 1/4"-20 bolts and use stainless bolts with washers under the head.

Shield the wire with black plastic flex material that is available at most automotive stores at any point where chafing or heat may be present.

Finally either use a proper swaging tool to crimp the correct size ends in place or solder them on or do both. Do not nick the wire or leave any strands outside the connector. Every little bit counts when you are running this distance.

Just use good common sense and take your time to lay it out properly.

Chuck Hurley

[Chuck Hurley]

Just happened to think, too little attention is paid to grounding. Make sure that you ground the battery to the frame. Run braided ground cables from each side of the bell housing to the frame. Make sure all items mounted on fiberglass (voltage regulator, starter solenoid, MSD box or similar) have ground wires running from the mounting points to a good ground. I run a heavy ground wire back to the trunk along with a hot at all times wire from the battery via the fuse box and an ignition turned on wire from the fuse box for whatever I might install in the trunk at a later date i.e. automatic antenna, CD changer, amplifier etc.) Use the ground from the front and connect it to all lights etc. and run the last light ground on the loop to chassis ground as well. Like suspenders and a belt but it is absolutely foolproof. Also make sure your gas tank is properly grounded, mounting screws are not enough, otherwise the fuel gauge will never work correctly.

Believe it or not I have a killer audio system that I can hear over the side pipes. Then again every one for 2 square miles can here it to.

I could go on about proper wiring for pages. I hope this helps.

Chuck

[lewismc]

Running the battery cable from the trunk of my EM cobra to the engine compartment was quite a dilemma for me. As stated in an eariler post, the danger of a direct short to ground should not be ignored. For that reason I decided NOT to run my cable along the frame (ground).
I decide to run my battery cable through the fiberglass behind the passenger seat. From there it runs below the passenger side kick plate until it exits the foot box into the engine compartment. My starter solenoid and voltage regulator is mounted to the engine side of the passengers foot box. If you bought the wiring harness from EM all of the wires should fit nicely. My ground wire is connected directly to the frame via the rollbar (inside the trunk). I also have a ground wire from the frame directly to the block.
A trunk mounted solenoid my have it's advantages but having an "always HOT" wire in your engine compartment may be advantagous. I use the always hot side of my solenoid for powering my MSD unit along with my electric fan. This configuration seems to work well for me.

Lewis Mc Murtrie

[tim]

Roger, I used a gel-cell type battery to keep any fumes from venting into the trunk and possibly hurting other electronics I have mounted back there. I actually use 1/0 welding lead cable from a local welding supply shop. Like Lewis my ground goes to the frame at the roll bar mount in the trunk. I ran the positive cable through a master disconect switch in the trunk through the trunk floor and along the inside of the passenger side frame rail. I mounted the cable to the frame with adel clamps which are rubber cushion type clamps to you. I have an airplane supply store local that sell these type of clamps really reasonably priced and unlike the automotive market I can get them in 1/32" incraments. So all the adel clamps I use fit really tight so there is no moving around. My selenoid is mounted on the fire wall above the foot box but over towards the engine so the cable comes up from the frame behind the headers and mounts with adel clamps to the inside of the transmission tunnel. I crimped all the cable ends on the cables with a crimping tool and sealed them with heat shrink tubing. (soldering tends to atract moisture and cause corosion). If your EM frame is newer there should be a 3/8-16 threaded bung welded in the passenger side motor mount this is to pick up your ground in the engine compartment. Run a battery cable from the frame to the motor and an 8 or 10 gage from the frame to the grounds in you engine compartment. I hope this helps.
Tim

[Whaler]

I was looking at your suggestion.....What do the guys do when they need a decent positve up at the front end thats energized all the time?
I like your suggestion but the need for another hot defeats this one.

IE gauges fan igniton etc etc.

Tim

[Cobra20646]

Tim,
I think what Dan was talking about had to do with the gauge of the wire going up front.
If a 1-0 wire shorted somewhere along its length, it would hump many amps for a long time before melting like a fuse ........ resulting in major heating of something and no doubt causing a fire before the battery finally gave it up.
A smaller gauge wire could be fused in the trunk, and not present the same fire hazard.
- Jim -

[Whaler]

Thanks Jim....
Imagine 850 CCAmps shorted to ground...run for the hills!!

I have to run a line for the battery feed to the front solenoid etc so I read this thread over pretty well.

Tim

[Cobra20646]

Tim,
Yeah, that's the beauty of building these cars ourselves. We can do what feels comfortable and safe. I may have an entirely different opinion of how/where to mount the battery, or solenoid, compared to everyone else. I mounted my battery in the trunk and ran a single feed directly to the junction post on the starter solenoid. Probably the majority of the cars out there have done the same thing. The comfort and safety issue comes up as to "how" we did it. Taking pains to see to it that this lead stays put without chafing, and routing it away from moving parts and hot headers, etc.
Good luck with your build.
- Jim -