Lotus Elan

Battery Negative Wire

PostPost by: William2 » Fri Oct 18, 2013 5:00 pm

What is the concensus on whether it is worthwhile running a thick wire from the battery negative terminal to the engine mounting to improve starting, etc?
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PostPost by: holywood3645 » Fri Oct 18, 2013 6:09 pm

It can't do any harm.
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PostPost by: gjz30075 » Fri Oct 18, 2013 6:46 pm

There's got to be other issues going on to prevent good starting. I've never (knock on wood) had starting issues due to the factory cable arrangement. Bad, corroded grounds: yes. Loose cables: yes.

I ditched all my factory issued cables due to corrosion under the coating that couldn't be seen and replace them with #2 welding cable. Yes, it was difficult to run the positive cable through the car to the solenoid but well worth it. Ground cable (#2 welding cable) still goes to the chassis mount in the boot/trunk. I also replaced the cable that goes from the solenoid to the starter. Zero issues. If you're going through the trouble of running a cable from the boot to the engine, just run a good, known cable for the positive instead.

So, I guess to answer the question, I don't think it will be worthwhile.

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PostPost by: StressCraxx » Fri Oct 18, 2013 6:55 pm

Please consider the entire circuit and all of the connections.
Battery terminals, the earthing connector to the chassis, the earthing strap to the engine, connections at the starter solenoid, and of course at the starter.

Each one must be clean and without corrosion with good electrical contact.

They all matter.
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PostPost by: oldchieft » Fri Oct 18, 2013 7:36 pm

No such thing as too much bonding.

I ran a cable from the starter mounting bolt to the chassis.

It did not cure the fault but I left it in place anyway.

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PostPost by: stugilmour » Fri Oct 18, 2013 8:22 pm

Common mod for battery ground is to move it from the bottom of the boot to the tapped chassis bolt on the front face of the right rear tower. Gets good purchase and contact with chassis in the tapped hole. Less road moisture up there I think.

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PostPost by: tcsoar » Sat Oct 19, 2013 11:14 am

When I did my electrics I a bolted a piece of tinned copper bar to the three chassis earthing points. Each bar had a series of threaded studs through them to connect the earths from the car. I also run a 25mm cable from the battery to the first bar in the boot, then linked this through to the bar behind the dash and onto the bar in the engine bay. I have also put two earth straps between the engine and the chassis, one across either mount.

May be overkill but had the kit to hand so decided to use it.

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