Install Charging Circuit At Controller

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This describes installing appropriately crimped and terminated cables onto the Sevcon controller's DC terminals.

Warning Warning: This procedure, if performed imprecisely, can result in irreversible damage to your powertrain, fire, injury, and even death.
Motivation
The officially recommended charging inlet is the Accessory Charging Port, which is fused to less than the 1C limit.
In order to achieve 1C charging, some bypass is required for at least one charging subsystem.
One may run one charging system through the port and one through the controller.
Mechanism
The Sevcon Gen4 controller has a series of terminals: M1, B-, M2, B+, M3.
B+ and B- are battery side terminals used mostly for input power but also supply power back to the battery via regen.
Requirements
Planned route and matching cable length from the controller to the charger.
See the Sevcon Gen4 product manual under Connecting power cables.
  • Keep cable runs short
  • Minimize current loops by keeping positive and negative cables as close together as possible.
  • Route cables away from the LED if you intend to make this visible under normal operating conditions.
  • Minimize bending and avoid touching the protective riser brackets around the terminals.
Terminal Bolt Concerns
Connect your power cables using the original bolts.
  • They are sized to clamp one ring lug thickness.
  • Use a longer bolt (of the same material!) if you are fastening more than one ring lug.
  • Minimum thread engagement = 10mm.
  • Maximum bolt penetration = 15mm.
For the Power Tank, longer terminal bolts (by 5mm likely) may be required to ensure the right amount of thread engagement.
Disclaimer Disclaimer: TBD acquiring the right bolts (measurements and alloys)
Materials
  • Red and black cables (4AWG rated for 80A) crimped to M8 ring terminal lugs.
  • Anderson SBS75X brown or red for charger connection, again the cables require impeccable professional crimping.
Warning Warning: An appropriate crimp tool and skills to use are not adequately specified online. Power cable crimping should only be performed by a practiced and reviewed professional with specific experience in this application.
Tools
  • Torque wrench specifically suitable for low-torque, precise specifications and socket.
  • Small Philips-head screwdriver (PH1?).
Warning Warning: Controller terminal bolts are made of a soft conductive metal and should not be manipulated with any excess force.
  • Cross-threading or any distortion or excess or imbalanced compression of the bolt threads may result in excess thermal stresses under power.
  • Poor conduction between the bolt threads, head, and the terminals may result in excessive heat and fire while riding.
  • Sevcon terminal bolts are made of an unspecified alloy, and do not have a known safe replacement.
    Store-bought bolts of the same shape may result in excessive heating and fire while riding
Steps
  1. Perform a lockout on the powertrain.
  2. Remove the seat.
  3. Controller verified fully de-energized.
    Warning Warning: Proceeding without completely verification is highly dangerous and could result in injury or destructive damage to equipment.
  4. Record the existing cable layout via photograph to preserve after the operation.
    Disclaimer Disclaimer: Do not trust illustrations given here - internal cable layouts might vary for any reason.
  5. Gently loosen the bolts fastening the leads on B+ and B-.
    Warning Warning: Ensure the breaking torque is limited by your tool to not much more than the specification (7-12 ft-lbs) to tighten the terminal bolts later.
  6. Place the cable leads over the terminals as follows:
    ColorTerminal
    RedB+
    BlackB-
    Form a stack from bottom to top of:
    File:Controller charge connection lead stack.jpeg
    Charge connection terminal stack
    1. Monolith terminal. in background of photo
    2. (Optional) Power Tank terminal.
    3. Charger terminal.
    4. (For B- Only) Ground reference terminal. photo note: this is incorrectly shown between/below the charger terminal
    5. Washer.
    6. Terminal bolt.
  7. Ensure that the route for the battery leads is the same as before.
  8. Ensure that the route for the charger leads minimizes bending and does not contact the protective riser brackets around the terminals.
    File:Controller charge connection routing.jpeg
    Controller charge connection routing (example)
  9. Gently but firmly re-tighten the bolts on B+ and B- to 7 Nm ± 1 Nm (6.2ft-lbs) per Sevcon (also recommended 7-12 ft-lbs).
  10. Confirm electrical connectivity from each terminal to the Anderson connector that terminates the other end of the charger cable leads.
    1. While still de-energized, re-confirm there is no DC voltage at the terminals.
    2. Verify low/no resistance from the bolt head at B- to the end of the black cable's lead inside the Anderson connector.
    3. Verify low/no resistance from the bolt head at B+ to the end of the red cable's lead inside the Anderson connector.
  11. Prepare the working area for live testing:
    1. Remove any tools or stray materials from the surface of the controller.
    2. Route the new charging connection so that it rests away from any conductive elements, including the frame.
  12. Test live without the charger.
    1. Key the vehicle on.
      • Immediately key the vehicle off on any sign of an electrical fault.
      • Verify the contactor closes.
      • Verify that there are no reported errors, or only precharge warnings.
      • Check DC voltage across the red and black terminals in the Anderson connector housing; it should match expected battery voltage exactly.
  13. Test charging.
    Disclaimer Disclaimer: TBD Full safety procedure and checklist
  14. Fully de-energize the controller again for maintenance close-out.
  15. Route the new charging connector to its intended destination.
    Ensure that the new cabling cannot be chafed by the edge of the controller cover.
    Ensure that the connector is securely positioned so that it will not strain the controller lug connections or the terminals within the connector housing.
    Ensure that the connector is placed away from splash and dust weathering.
  16. Re-fasten the controller cover.
  17. Re-install the seat.
References