Di2 6870 discharging issue

[RuskinAsh]

Hello,

I had the Di2 Ultegra 6870 working great for about 6 months, and now the internal battery just refuses to stay charged.
A single click on the shifter fully discharges the battery, even after a full charge. Even after re-inserting the cables, the problem remains. The groupset works perfectly when plugged in for charging.

The diagnostic tool says all components are working fine!

I have no one to swap components with to see which one is defective, any thoughts?
It's too expensive to just make a guess and buy a battery or the junction boxes. I was hoping you guys would know in which component the problem lies.

[BdaGhisallo]

I haven't encountered or heard of this particular issue in nine years of DI2 use but if you say everything works fine when the battery is charged I have to believe the fault lies in the battery or the A junction box. Either the battery is pooched or the junction box is somehow mis-reading the charge level and some how disabling it.

I have had A junction boxes go bad and short things out, leading to very quick battery discharging, but nothing on the order of what you describe.

Do you have the new internal battery or the previous gen?

[ooo]

What is currency of usb input? If it is <1A usb , try >1A usb power source

When charging from 0, stop charging every 5 minutes and check battery level, take a note how much time it takes to charge to 25%, 50%, 100%

[RuskinAsh]

@BdaGhisallo the internal battery is of the previous generation, all the components are up to date with the latest firmware. I have long suspected the Junction Box A, let's see

[RuskinAsh]

@ooo haven't really observed that, was using a normal mobile USB charger. I'll look into it.