Battery and Motor Cables

The high voltage cables carrying current from the battery pack to the motors will be discussed here.

• Flexibility

  • These cables will likely be moved around, plugged in, unplugged, etc. many times during debugging and testing. This means we need a high strand count in the cables.

• Gauge

  • The wires must have sufficiently low resistance in order to minimize the resistive power losses and increase the efficiency of the drivetrain. We have selected a minimum of 4AWG (25mm2) for DC battery and 6AWG (16mm2) for DC motor controller wires.

• Color

  • We will keep all high voltage cable ORANGE, as the recommended industry standard (recommended by SAE, though I can’t find the document). Black or red heatshrink will be used on the ends of the wires to denote positive and negative high voltage wires.

• Shielding

  • MSXII did not have shielded HV cables, and no significant issues were observed (after switching to differential communications). I would love to do more research into this, but for now we will stick with non shielded wire.

• Insulation

  • Concerns with PVC insulation - it will slowly pull back from the connector over time, as it does when soldering

  • Crosslinking and irradiation explained here: https://chargedevs.com/features/cable-sizing-and-selection-for-ev-systems/

  • We will go for crosslinked, irradiated insulation, per the recommendations from Champlain Cable:

For reference, I believe that most welding cable is EPDM insulation.

Tritium Cable Recommendation:

This is essentially double insulated welding cable.

IEWC Part Numbers:

32102862

Huber + Scuhner 16mm2 1kV XLPO (Crosslinked polyolefin), double insulation

Champlain Cable:

EXRAD--HVFXI-16 (or 20)

EXRAD-XLE6-6X (or 4X)

EXRAD-FXIF-16 (or 20)

EXRAD-FX-6XX (or 4XX)

We would love for IEWC to provide recommendations or a call on speccing wires, and see what they have available.

Good discussion on cable lugs and why speccing the proper one for the type of cable you have is important - finer strands will lead to a physically smaller cable, so a proper flanged or bellmouth lug is required.
https://www.solarpaneltalk.com/forum/off-grid-solar/off-grid-solar-panel-systems/351593-is-welding-cable-suitable-for-battery-systems

Also be sure to use silicone grease on the copper cables to prevent oxidation.