# Cable size



## albo2 (Oct 4, 2011)

Hi all I have purchased some 50mm cabling, I have been informed that 70mm would really be a better choice, I'm running the HPEV AC50 with the 650 amp controller, the 50mm cabling is rated 500 amps, I would have thought this would be ample any comments.


----------



## Ziggythewiz (May 16, 2010)

Assuming you mean crossectional area, that would be almost a 0 gauge, while 70 would be over 00. We usually use 0 or 00 for road-going EVs. Most people would say 0 is fine for the battery circuit, with 00 for the motor-controller circuit, but we tend to over-size things.

Your max is 650, what do you expect your average draw to be?


----------



## skooler (Mar 26, 2011)

I'd say 50mm is fine for 600amps

I run 600amps on my rx8 with 50mm cable. Not even slightly warm after flooring it for a while.

Connections are the most important part.

Cheers,

Mike


----------



## Woodsmith (Jun 5, 2008)

Most of the time you won't be on full power and when you are it is usually a short burst so apparently slightly undersized cables will be ok.

If you are planning on sustained periods of very high power then you will need bigger cables to reduce over heating and losses.

I'd say use what you have and monitor. If you need to you can always replace the shorter controller to motor cables with 70^2mm later.
As has been said, good quality connections are important.



I run 35^2mm on my tractor (48v, 400A), and I have some 70^2mm for my trike.

I might run the 70^2mm for the whole circuit, or just for the motor with 50^2mm for the pack.

Then again I also have some 95^2mm so I might run that for the motor with the 70^2mm for the pack. That would weigh a fair bit more though.


----------



## ricklearned (Mar 3, 2012)

Ziggythewiz said:


> Assuming you mean crossectional area, that would be almost a 0 gauge, while 70 would be over 00. We usually use 0 or 00 for road-going EVs. Most people would say 0 is fine for the battery circuit, with 00 for the motor-controller circuit, but we tend to over-size things.
> 
> Your max is 650, what do you expect your average draw to be?


Unless its an AC motor with a 3phase controller, then you probably only need 0 for the motor-controller circuit.


----------



## PStechPaul (May 1, 2012)

If there are any high frequency components of the current being carried, the effective resistance of thick cables and bus bars may increase due to skin effect and proximity effect. Here is some information:

http://www.copperinfo.co.uk/busbars/pub22-copper-for-busbars/sec4.htm

Here is a plot of the equivalent resistance of an 18AWG wire, straight and wound into a coil of 1 to 3 turns. 










It is best to bundle multiple wires together and also twist pairs and triples of conductors to minimize inductance. This is not as critical for battery connection, assuming that there is a DC link capacitor for drawing the high current pulses. But it can eb critical for motor leads.


----------



## albo2 (Oct 4, 2011)

Ziggythewiz said:


> Assuming you mean crossectional area, that would be almost a 0 gauge, while 70 would be over 00. We usually use 0 or 00 for road-going EVs. Most people would say 0 is fine for the battery circuit, with 00 for the motor-controller circuit, but we tend to over-size things.
> 
> Your max is 650, what do you expect your average draw to be?



I expect to averaging 200 amps, with the motor cabling it will be very short as the controller is on top of the motor there are 3 cables from controller to motr I would have thought they wouldn't need that heavier cable as they will be load sharing


----------



## albo2 (Oct 4, 2011)

thanks for all your help guys this forum has been a great source of info I wouldn't have had the guts to do this without knowing your support is out there,

Infact Istill feel a bit apprehensive with the idea of me playing with high voltage


----------

