Firedog,
sorry for late answer I was away.
As you can see from my Lithium conversion schematics I charge completely outside EPLUS drive.
This is my understanding that State of Charge SOC display bars are displayed based on Columb count by measuring charge going into original NMH battery and discharge Columb count.
When I was doing conversion I was very afraid that I would discharge my Lithium batt and finally I would get cut off.
Instead I am getting blinking one bar on both of my EPLUSEs.
As I guess power cut off is based on Columb discharge count AND voltage. So high voltage of our Lithium packs even after many kilometers keeps system from shutting down.
I also noticed that I have to wait longer for display to lit up after I connect Lithium to lower power board.
On every EPLUS display/controller sends enquiry also call handshake to both: battery upper board and to motor electronics, only motor electronics are ID to this particular disp/ctr. battery upper board is not ID.
in your case - for some reason your upper board did not respond to handshake.
why
there are many reasons for that - short on board, PIC chip lost power/5V/ , RS 485 comm. could not be executed , etc.
10 min time out - when no buttons or throttle use for 10 min.