Replacing bad cell #65

The ECE Lotus has 4 battery packs with in total 100 cells. Based on the fiber optical cable which runs from the VMS thru all 4 packs I guessed that cell #65 would be in pack #3. Pack #1 has 24 cells and is behind the driver seat. Pack #2 is above the gearbox and Pack #3 is next to it, both have 24 cells. Pack #4 is behind the passengers seat an has 28 cells

Lifting battery pack #3

Lifting battery pack #3

Pack #3 removed

Pack #3 removed, Pack #2 above the gearbox and Pack#4 slightly vissible

After Pack #3 was removed it was placed up-side down and opened up.

Battery pack (Up side down) showing wires to LOM modules

Battery pack (Up side down) showing wires to LOM modules

The top cell of the lower 8 cells was defect.

Disassemble battery pack

Removing the bad cell from the pack

The replacements cell was at it’s nominal voltage of 3.7V it need precharging to match the other cells at 4.10V. The picture shows two cells in serie.


Precharging the replacement cel

After charging the pack was assembled and bench tested. Each set of two cells is monitored by LOMs (Lithium Optical Monitoring system by AC Propulsion). Each LOM is connected to the next cell with a fiber cable.

Bench test of new assembled pack of 8 cells.

Bench test of new assembled pack of 8 cells.

Lom module

LOM module

LOM module

LOM Utility test software screendump.

New cel 65 in pack

New cel 65 in pack

After some testing the 8 cells where placed back in Pack #3 and the car was put together. I’m getting better at it 🙂

The VMS showing nice voltage levels (first line). The second line shows the temp of the cells. Pack #3 is a few degrees warmer since 8 of the cells where in doors for a day or two.

VMS display after replacement of defect cell #65

4 thoughts on “Replacing bad cell #65

  1. Hi Gaby,

    Good to find and read your posts of the Elise. She’s a beauty.

    I also own an ECE converted car. A golf with registration 27-JND-2. Same power train it seems. I’d like to get in contact and see if we can exchange info.


  2. I am interested in your experience with the AC Propulsion’s LOM. I have several battery modules from E-Moli, which were used in BMWs, that have a LOM 2.0 module. I am looking for any information about how to interface with the LOM. Any help would be greatly appreciated.

    • Hi Jacob,
      as you can see in my post I managed to build my own LOM interface. If you want I can share my designs with you. Where are going to use the batteries for?
      Best regards

Leave a Reply

Your email address will not be published. Required fields are marked *