Nice work - testing the ability to read and write and read back a new blank chip seems to be the sensible thing to do to verify the results we're getting, otherwise there are too many unknowns if we're not even sure our diagnostic equipment is working properly...
Regarding CMU numbering I found a little nugget in the official i-Miev service manuals that may not have been spotted before. I think we've all seen and referred to these manuals before:http://mmc-manuals.ru/manuals/i-miev/on ... dex_M1.htm
In 54D-ELECTRIC MOTOR UNIT AND TRACTION BATTERY -> BATTERY MANAGEMENT UNIT (BMU) AND TRACTION BATTERY -> DIAGNOSIS FUNCTION we have the following page describing how to use the MUT-III diagnostic tool with the battery:http://mmc-manuals.ru/manuals/i-miev/on ... 800ENG.HTM
And this caught my eye:
NUMBERING CMU ID PROCEDURE
Because done at the factory, numbering the CMU ID is not necessary.
We know this statement is true as the CMU's are numbered (somehow) at the factory, however why even mention at all that the "numbering CMU ID procedure" is not necessary unless the diagnostic tool provides an option to do this ?
This implies to me that there MIGHT be a diagnostic procedure that can be run on a MUT-III to trigger a renumber of the CMU's.
From what I remember of previous discussion on this the speculation was that there is a daisy chain signal between the CMU boards that is wired in a certain order which would allow the CMU's to "self organise" themselves into the correct CanBUS ID order when commanded to do so. This is not something you would want to do all the time so it makes sense that it would be a diagnostic procedure that can be initiated at the factory and also on the MUT-III diagnostic tool.
Perhaps they originally planned for module level swapping at dealers to be possible, and thus built the CMU numbering procedure into the diagnostic tool, but later decided that dealers would only do whole pack replacements (less training required) and thus the advice is now that the numbering CMU ID procedure is not necessary and should not be used by the dealer.
The question is, who is brave enough to poke around in the MUT-III settings to see if they can find this renumbering procedure ? Does anyone have a scrap car which they can still communicate with the battery pack with ?
I will have a poke around in Diagbox on my car at some point however the Diagbox UI is very different and is not a one for one replication of the options in the MUT-III, so potentially CMU renumbering may not be possible in Diagbox. It is something that could potentially be added to a third party tool like Hobdrive though.
Martin in this Speak EV thread
is having to repair/replace a CMU with a faulty LTC chip and has a spare CMU board on hand but doesn't know which number it is, I've suggested the possibility of trying to find and use the CMU renumbering procedure so he might be the first to give it a try if it does exist!
Edit: It also occurs to me that for the renumber procedure to work even in the case that you start with a clash of CanBus ID's between two or more boards, there would have to be an out of band hardware control signal coming from somewhere else to initiate the renumber - didn't we find a non-Canbus control signal going from the BMU to the CMU's in the schematics ? Maybe the diagnostic tool sends a CanBus command to the BMU to initiate the process and the BMU then sends the necessary non-Canbus signal to the CMU's ?
Finding the secret sauce to easily renumber CMU's using a readily available third party diagnostic tool such as Hobdrive / icarsoft etc (no soldering/eeprom swapping) would be a breakthrough for the DIY and aftermarket repair and servicing of these battery packs.