Shimano Ultegra 8170 shifter battery issue

Equipment
1

My right shifter has multiple times stopped working with almost full battery. First time it gave a low battery warning before dying maybe 30min later. Second time just a few weeks later it just stopped working. Now it’s happening more and more often without warning.

I assumed something was draining the battery but when I put the old battery back it shows green light and it’s working. So it’s some kind of software or contact issue. Firmware up to date, no stuck buttons. Taken the wires off battery and put back nothing helps.

Any idea what could be causing this? I need to order the parts to wire the shifters but I would still like to fix the issue. I’ve contacted the seller but it’s from Aliexpress so I’m not expecting much.

2

I’m not sure what you man by “taken the wires off battery”, there’s no wires on the battery, it slids into a slot. Anyway, first thing to try is electronics contact cleaner, do the battery and the contacts inside the shifter. It’s also possible the spring holding the battery in has gotten damaged or was defective; I’m not sure if that’s repairable.

3

I meant I took the wires of the main di2 battery as it is supposed to somehow reset the system. I will try to clean the contacts but the lever is almost new so I doubt that’s the problem.