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Ultegra Di2 battery/ cable stupidity

Chris522Chris522 Posts: 3
edited January 2019 in Workshop
Hi all. At risk of highlighting my own stupidity and encouraging a stream of abuse I need some help.

When disassembling my bike for transportation I managed to pull the di2 cable out of the seat post battery which has damaged (in absence of knowing the right words here) both the port in the battery and the cable plug. Such that they no longer connect.

Does anyone have any ideas on how to fix the issue or am I looking at a new battery and new cable routing?

Any help great / abuse appreciated!


  • pilot_petepilot_pete Posts: 2,120
    Pictures of the battery and cable would help. Worst case is you will need a new battery and one new cable the same length as the damaged one (or longer). Chances are it routes to the Junction B in your bottom bracket. Remove the crank to get access and to find the other end of said cable. See the second picture here note that there is no bottom bracket installed in that picture. You may/ may not be able to get to your Junction B with the bottom bracket left in.

    Depending on the damage to the battery, you may be able to take the damaged cable and shorten it, from the good end, soldering the wires from the cut off end to the correct terminals on the battery. Some heat shrink over the bottom end of the battery onto the cable once confirmed working would leave you with a ‘tail’ with a cable end socket.

    You could then buy a new cable and join that to your ‘tail’ using a EW-JC200 inline connector.

  • Thanks Pilot Pete. I’ll have a look for Junction B! Appreciate the help.
  • pilot_petepilot_pete Posts: 2,120 here’s a very simplistic wiring diagram. It really is as simple as that...

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