Friday, November 21, 2008

Buying Heavy Battery Cable

I spent last night visualizing how I could most effectively connect all the traction batteries with the least amount of welding cable and the shortest distance to the controller and motor.

This morning I took some thick rope to serve as a fake battery cable and used it to measure the long cable lengths needed to connect the front and rear batteries. Measuring this is important because welding cable is expensive and you need to get enough but not too much. Here are the measurements I came up with:

Rear battery rack:
  • battery 1 to 2: 6"
  • battery 2 to 3: 12"
  • battery 3 to 4: 6"
  • battery 4 to 5: 12"
  • battery 5 to side battery: 14"
  • battery 5 underneath car, through the circuit breaker to the contactor: 16 1/2 feet
Front batteries:
  • front battery 1 to 2: 6"
  • front battery 2 to firewall battery 1: 34"
  • firewall battery 2 to 3: 6"
  • firewall battery 3 to 4: 6"
  • firewall battery 4 underneath car to rear battery 1: 13 1/2 feet
Controller connections
  • controller to motor: 19"
  • controller to front battery 1: 14"
  • controller to contactor: 8"
  • contactor to motor: 15"
All in all, I calculated about 44 feet of welding cable. I already have 13 feet, so I purchased 33 more feet to have a little extra. For those in the Portland, OR area, I highly recommend United Welding Supply up on MLK for 2/0 cable. The price is based on the commodity price of copper and was $2.90 a foot today. This compares to $4.75/ft from Electro Automotive, $6.00/ft at Parkrose Hardware and $8.85/ft at

I also dropped by Napa Auto parts to pick up all the fuse holders required for the BatMon battery monitors. I'm thinking this is going to end up like wiring spaghetti, but we'll see.

Have a great weekend, everyone.

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