I am planning out a Di2 setup with the Ultegra 6870 series, but I don't need to run a front derailleur. I am making a 1x11 setup. Is it possible to connect the shift level (I am using the ST-R785 levers) directly to Junction B, so I don't need a Junction A at all?
I know for internal batteries, a Junction A is required for charging, but with an external battery, it shouldn't be necessary. Does Junction A do anything else essential? It'd be awesome if someone with a Di2 setup (especially an Ultegra 6870) could test this too.