Di2 battery draining

Hi, My di2 is draining to flat after 3 or 4 days, fitted a new battery,same issue, just wondering if people have had the same issue and possibly solutions…

Disconnect components then reconnect one at a time. It should be easy enough to figure out which one is causing the drain.

I’m sure I’ve heard about wires rubbing through and shorting out which can also cause battery drain.

Sadly it could be anything. I’ve had a case of a worn wire and another with a rear derailleur which, with no accident damage just started draining the battery.

Some LBS have proper diagnostic equipment for Di2 which can trace the drain.

Is the system slow/finicky to charge? Do you get a solid light or a pulsing one on the charger?

Charges fine with a solid light.

Yes and it’s a bit of a pain to diagnose.

First up is connect it to a computer or the app. See if that shown anything. The consumer one isn’t as good as the workshop one but it may show something.

Then it’s just a question of methodically working through things as suggested above.

Visually check cables
Check connections (damp, corrosion, engagement)
Check components (visible damage)

The you disconnect one thing for long enough to see if the power drops.

For me it was a damaged rear mech. It was letting in water and shorting. Cables are likely, junction boxes also if they are low in the frame and often damp (e.g. around the BB somewhere).

Thanks for the responses, I’ll try and disconnect compenents and hopefully find the culprit, through process of elimination.

Cars and electronics, PITA, bikes and electronics…PITFA