Starter motor cable

[batman3481]

I have a Triumph-based Roadster with a 2.5Ltr engine fitted with a Lucas M418G starter motor. Its maximum lock torque 17lbs/ft at 450amps. Should I use 345, 415 or 485 amp battery cable?
Many thanks in advance. Barry

[b_caswell]

Re: Starter motor cable

As the maximum draw would be around 450amps then the 485amp cable will leave a margin for overload.

If you are fitting the terminals your self then make sure you get a good connection.

[stevejgreen]

Re: Starter motor cable

My opinion.

The starter motor cable, from battery to motor, should never be different in size, or smaller, than the cable from the battery to the chassis.

The maximum current drawn will be limited by the batteries CCA rating, usually marked clearly on the battery itself and the cable size should be selected accordingly, taking into consideration that the duty cycle of a starter motor is measured in seconds, far from continuous.

[batman3481]

Re: Starter motor cable

Hi Ben
Thanks for that, it was as I expected.+it was wired up with a smaller cable from battery to chassis so both of you have put my mind at rest.
Barry

[b_caswell]

Re: Starter motor cable

I would also run a heavy negative direct from the battery to the engine as well as the engine being
earthed to the chassis.

[stevejgreen]

Re: Starter motor cable

I would also run a heavy negative direct from the battery to the engine as well as the engine being
earthed to the chassis.

I would echo that, bad earth connections are generally a nightmare on Kit cars throwing up multiple strange faults.