I was able to find 8 out of the 11 converted Lotus Elise.
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
After Pack #3 was removed it was placed up-side down and opened up.
The top cell of the lower 8 cells was defect.
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.
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.
LOM Utility test software screendump.
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.
Yesterday I visited the ECE Factory and talked to the engineer who converted my Lotus into an EV back in 2008. Learned a lot about the car. During my visit they where working on the Enexis Demo car.
One of the 100 cells, cell #65 is dying. This is noticeable under hard acceleration and the top speed has dropped to 141 Km/h.
It will be quite an operation to get to the defect cell. First te body needs to be removed and than I need to open the black box.