The 'E' Type Forum

I need to replace the power cable to the starter motor. Does anyone know what the current rating should be for this cable.

BIG.

The stall current for a starter motor will be in the order of 700amps; the running current ~250amps and the idle current 70amps.

That means if your engine is locked and not moving, the starter will try to pull a huge current and everything will get very warm. If it is turning the engine over, then it'll be pulling 150-400amps depending on how many cylinders fire up and once the engine is powering the car but before the pinion flies back into the housing, it'll be pulling 70amps or so.

You need a cable of similar thickness to that of the battery terminal cables.

It's also a good idea to put the battery positive cable eyelet right next to the starter motor cable eyelet and not at opposite ends of the through bolt onto the chassis. I'm sure you can work that one out.

kind regards
Marek

Thanks MarekH, much obliged.

Another way to do it is to run a dedicated starter cable directly from the +ve battery terminal to the starter motor. Then you can go as large as you like. I use 26 mm2. A secondary benefit of this; having a dedicated starter cable that bypasses the distribution terminal means this latter becomes relatively un-cluttered.
Only downside is that the battery terminal lugs need to be changed; to a type that provides for more than one cable to be connected. I also changed the battery, so that the terminal position and access arrangement would be as I wanted:

[

[

Hi Colin....if your going to use a thick cable for the + side then you need to use the same for the - side.....Steve

Yep. Ground return is also 26 mm2

Hi Colin..Great....must be an optical illusion your black links thinner than the red....Steve