Have the little screen connected to the Arduino and it is all working. Have finalised the design of the display graphics and implemented the 3 display pages I am going to use.
I also mounted the screen in its optional bezel for wall mounting.
Page 1 shows the bank voltage and the charge and load current, using 2 separate shunts measuring the incoming solar charge and the outgoing load.
The image below shows this page on the screen with the Arduino connected. The second and third page have minor changes.
Page 2 shows the cell monitor and a couple of additional buttons and a number display for the meter values.
Page 3 is almost the same like previously, just an additional button to switch the display back to page 1.
These are all the display objects I need to visualise the status of the BMS at any time. I can separate charge and load individually and can program the operational parameters.
A major nuisance is that the display still reboots randomly and 4D Systems has still not responded to the complaint, but that does not really surprise me. The display widgets are really not up to scratch. The meters run out of bounds when the values are transferred according to the scale but not normalised to a non zero low value. They also cannot cope with float values, only handle integers and for me this hole thing is good for hobby but not really ready for commercial use. The hardware is flimsy at best, especially the programmer and the use is quite inconvenient because the graphics have to be loaded from an SD card and the SD card has to be written separately from the flash memory of the display. This is really toy level in my book and not quite up to industrial standards although they might see it that way. There is more, but I am not doing development work fro them, so I will use my time for other things.
The images below show page 2 and 3 of the display with the cells in mV x 100 because the meter widget cannot deal with float numbers. neither for the labels of the scale nor for the values for the needle. This is really a joke when you think about it. Well, and there could be the solution that I may miss something very fundamental, but I doubt it. I would be happy to be wrong here, because I really don’t feel like programming my own widget in 4GL right now. I will eventually if they do not improve their software. I know that I am going to annoyed for the next 5 years whenever I look at it.