DIY Electric Car Forums banner

AC-150 VMSG LOM optical temperature sensors repair?

290 Views 0 Replies 1 Participant Last post by  Swing
Hi all,

I am checking if I can repair this older EV which was built with an AC-150 system.
In general most is working fine, but it is sometimes giving erratic cell temperatures, causing it to not want to drive (cell temperature exceeded)
The value changes are so fast and restoring, that it is clear the temperature readings are incorrect and the cell is most likely doing fine.

This drivetrain uses the VMSG as the battery manager, and I got some documentation out of that.
However, for the temperature sensor it refers to the "LOM documentation", LOM stands Lihium optical monitor
Is there anywhere I can find this LOM documentation? It looks like the LOM units are coming from AC-propulsion as well, but I am not sure about that.
There also seems to be some debugging software for it, which probably requires a hardware tool (serial to optical). Bonus points if I can find that.
But so far, I can't find anything offering that documentation or the hardware.

Apparently it is an optical network with boards that each monitor 2 cells (at least in what I could find). They tell you the cell voltage and temperature.
I found these pics online on a blog of some DIY EV work:
Computer hardware Electronic engineering Gas Electricity Cable


Circuit component Wood Machine Electrical wiring Wire


So the black and blue are optical.
I don't know the wiring, but it looks like 2x temperature sensors on the black wires, and probably + and - of each cell.

So perhaps one of the temperature sensors is broken and can be replaced without replacing the LOM board.

If anyone can point me towards a source for documentation or buying these LOM modules, that would be great.
I already tried calling AC propulsion and I have tried to leave them an e-mail via contact form but it also reported errors.

I don't have the car here. I am trying to judge if I should go there, to remove the battery cases and open everything up.
I might better come prepared. It is not my own car.

Thanks in advance
Top