Metalman
Thank you for feedback.
there are two rain-sensitive points on Eplus:
1. front data connector /same brand as on Tidal Force - HIROSE/
2. display/controller
solution for connector is to disconnect, slide heatshrink tubing even 2 inch long over up communication cable, connect , slide down just enough to cover lower part of connector maybe 1/4 inch , creating "skirt" . Next place some silicone into tubing at the top, next heatshrink with heatgun only upper part of tubing
You would have to streach this skirt with pliers to be able to connect.
To weather-proof display/controller I applied slicone , applied silicone around edge of glass window .

About batteries.
If they had approximately same usage it woud be no problem.

PIC chip on BMS runs the code/software/ , counts discharge, takes cell volt readings /in group of 5 cells/ and decides what to display.
For correct displaying it needs to register real low /cut off/ voltage and real after charge voltage.
When this low and high voltages change every charge and complete discharge , BMS can get "confused".
your extra hub is NOT battery B and still is seen as battery A.
Maybe Rick Ruggiero would know how to assaign status B to this extra hub.
350htrr,
I cannot even imagine paraller charging of two hub batteries.
you don't know but Eplus battery is much more complex than you think.
each hub battery has electronics buit-in, there are not just cells.