10 replies to this topic

[minbin 69]

anyone tell me what amp rating the battery to starter motor cable needs to be?

[HarrysMini]

I would use 300A. The Mini starter motor draws nowhere near that, but it's good to be safe and have some reserve.

[minbin 69]

thanks..yep always better to go over what it needs

[Sam]

I've got 170 amp cable in mine.

 

I'm not sure if a 300 amp cable would physically fit in the cable channel on the floorpan? The 170 amp only just fits.

[dklawson]

+1 on Sam's comment concerning cable size.  

 

Cables are typically referred to by their conductive area and the actual ampacity of that cable can vary based on the jacket material and how the cable is mounted.  The cable rating is also for continuous current.  The Mini starter will draw a lot of current but in short bursts.  So... fit the cable with the largest jacket diameter that will fit the track under the car body... and the largest amount of copper in square-millimeters.  Make sure you buy automotive cable or welding cable.  Both will have finer stranding to handle repeated flexing and vibration in an automobile.

[minbin 69]

thanks guys..i was looking at some 170amp car/welding cable on ebay wondering if that was man enough for the job

 

one like this?

 

http://www.ebay.co.u...=STRK:MEBIDX:IT

Edited by minbin 69, 18 May 2014 - 07:01 PM.

[HarrysMini]

300A does fit, I can't find the link of the one recommended to me, but the OD wasn't that big.

 

Edit: This is the one http://www.iem-servi...ails.asp?id=665

Edited by HarrysMini, 18 May 2014 - 07:10 PM.

[KernowCooper]

thanks guys..i was looking at some 170amp car/welding cable on ebay wondering if that was man enough for the job

 

one like this?

 

http://www.ebay.co.u...=STRK:MEBIDX:IT

They list in in the bumfp as 110a which is not enough I'm afraid, I use this http://www.iem-servi...ails.asp?id=665

12.2mm O/D

Edited by KernowCooper, 18 May 2014 - 07:12 PM.

[minbin 69]

sorry wrong link ok thanks i'll take a look

 

thats the one i was looking at

 

http://www.ebay.co.u...984.m1423.l2649

Edited by minbin 69, 18 May 2014 - 07:18 PM.

[KernowCooper]

Not big enough 170 amps, the one in my link is 300a, the one I recommended for Harry in another post, good quality cable helps fight volt drop with battery in the boot

Edited by KernowCooper, 18 May 2014 - 10:39 PM.

[Captain Mainwaring]

I would use 300A. The Mini starter motor draws nowhere near that, but it's good to be safe and have some reserve.

 

It's not about reserve it's about voltage drop - bigger the cable, the smaller the voltage drop and since the ignition system is run off the same supply as the starter, the bigger the voltage drop during cranking, the weaker the spark could end up, just when you need a hot spark.