QUESTION: I’ve got a bike with ultegra di2 electronic shifting after 2 years and 10k miles With no problems. The system won’t stay charged more then 48 hrs. The Bike has spent most of the summer in the local bike store where they swapped the main cable And the battery. It still Doesn’t work. Any suggestions?
As a work around I just charge it up before every ride when charge up my lights. – Chuck M.
Jim Langley responds: The Di2 batteries are usually pretty good. Are you sure your charger is okay? It needs to put out enough juice to fully charge the battery, which is supposed to take about 1.5 to 3 hours for a full charge depending on which battery type you have.
Do you know if the bike shop used the Shimano E-tube diagnostics to “look under the hood” to find the issue? You can learn more about that and how to do it here: https://e-tubeproject.shimano.com/about/
It seems to me that it has to be a bad battery, a bad charger or that your system is using too much power for some reason. Maybe there’s a draw on the system when you’re not riding, like from a short in a wire? Usually all or some of the wires run through the frame. It would be pretty easy for some sharp edge inside to cut through the wire insulation, for example. It might even happen where it exits the holes in the bars and frame.
I have never used the diagnostic tool, but I believe it would be able to pinpoint what’s going on so you can find it and fix it.
I would have expected a Shimano authorized dealer to be able to diagnose and fix the problem. Since the shop you tried didn’t, maybe you should contact Shimano and have them recommend another shop who can help?
I hope something here helps you fix the issue and get your Di2 working properly again.