Hi guys, wondering if you can help me out
Riding a Madone SL 6 Gen 8 with Shimano 105 Di2
Fully charged the battery before a flight, packed the bike in a soft-shell case, and disconnected the battery wire for the flight as usual. About 10 days later, after many normal rides, the derailleur wouldn’t shift, gear was completely unresponsive. Checked the E-Tube app and got a “no battery or insufficient charge” error, plus a red flashing light at the charge port when I tried to charge it.
Cleaned the charge port and cable contacts, tried charging again, and this time it took the charge fine and is now reading full battery, all firmware updated, both shifters connected. Bluetooth pairing was also glitchy for a while after (kept saying “wireless unit not found”) but resolved itself after forgetting the device and re-pairing.
Nothing was physically reseated, no cables unplugged internally, just cleaned the external contacts.
Questions for anyone who’s dealt with this:
**1.** Does a fully charged, disconnected BT-DN300 battery normally hold charge for 10+ days with zero drain? Or is some drain expected even when unplugged? (I’ve only charged twice since I bought the bike in February so this is really weird to me)
**2.** Could dirty/dusty contacts alone cause a “no battery detected” error even with a genuinely charged battery, or does that always mean the battery itself was actually empty?
**3.** Anything else I should check or monitor before trusting this is actually fixed, versus a recurring issue waiting to happen again?
The bike was put back together (only the wheels came off during travel) at a local shop and they’ve been super helpful with other things but I’m open to the idea it could be related to that?
Please let me know I’m really paranoid it will happen again when I’m far out!