My bike was on the trainer for a couple weeks.

One morning, Di2 stopped responding.

  • No shifting
  • No light at junction box at all
  • charger doesn't light up orange when plugged in
  • etube doesn't detect anything.

Tried different battery, same issue.

Tried different A junction box, same issue.

Tried plugging the battery straight to the A junction box with the charger only, no activity either.

I'm running out of ideas!

Let me know if you have a potential solution.


EDIT : I'm suspecting the charger not working and the batteries being flat. No lights showing on the charger at any time and not detected by my laptop when I plug it in.

  • I know you said the bike has been on a trainer. However, the symptoms you described could occur if the battery had been disconnected from the rest of the system. After all, we don’t plug the battery itself into the charger, we plug the charger into the junction box (usually mounted under the stem, or in your bar end). Is it at all possible that this happened? If you’ve done any work on the system wiring, did you use the stock Shimano connector/disconnecter tool? – Weiwen Ng Feb 7 '20 at 19:24

I've borrowed a charger from a bike shop nearby and it was my charger that was dead.

Not sure how the battery drained itself completely in the first place but I charged the system and it came back to life.

Underneath the charger, there is the production date and mine was from 04/2013 so it's quite old and could have just died.

  • Check your USB cable that connects the charger to the laptop/wall-charger. That one may also be dead. – Carel Feb 8 '20 at 15:40
  • Tested and no more luck there. Bought a new one, they are not cheap! – Val F. Feb 25 '20 at 21:38

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