18
Sep
2009
2/0 Welding cable for the EV battery pack
There are plenty of EV sites on the web and all seem to offer different advice on the size of cable needed for the battery pack. I have read some say 1/0 welding cable is fine, while others recommend up to 4/0 welding cable. (Welding cable seems to be the best choice since it very flexible and ideal for routing through the car). I am going to assume the 4/0 is for the higher volt/amp packs... i.e. 144 volts or greater. Since our little electric vehicle is planned at only 48 volts I would think that the 1/0 welding cable would do just fine. But since I found a great deal on a 50 foot, 2/0 welding cable (free shipping) and to top it off it is made in the USA. The 2/0 cable also allows me to change the battery pack voltage later if so desired without the need to upgrade all the cable.
Here is where I purchased my welding cable :: Harris Welding Supply.
50 foot of 2/0 welding cable
The diameter of the cable is determined by the amperage of the system and not by the voltage. Voltage determines the type and thickness of insulation you need. *Most* welding cable is 600V DC rated, but it’s printed on the insulation jacket, so just check. “Safe” voltage is about 50% of rated for most applications where cable movement is possible due to the capacity to rub and chaffe.
Cable is not amerage rated because the resistivity of the cable increases with length, cable is rated in ohms per foot (or meter). The longer the cable run, the larger the cable musst be to avoid excessive voltage drop. Same with amperage, the greater the amperage, the larger the cable must be.
All that being said, there is nothing readily available, lower in resistance in terms of conneections, than flattened copper pipe. One main goal should be to reduce the cable lengths when ever and where ever possible.
Thanks John,
I actually just read some information about the 1000 amp Zilla controllers use 4/0 cable. So, I think my 2/0 is overkill with my system. But, room to grow a bit if needed it looks.
Also, I think the longest cable run will be from front (battery pack) to rear (controller and motor)… so maybe 7 feet. The rest I will try to keep short.