Today I have disassembled three battery modules out of a BMW i3 battery pack.
In total I will mount three modules which will sum up to 7.9kWh. This should give a range of about 150 - 250km.
After unmounting the modules I directly started modifying the sense cabling to adapt it to a different battery management system. I have finished the first today. In the next few days I will probably finish the other two
Here I will show you a little part of the CityEL project. It is a digital speedometer, which gets it's data over CAN bus from the battery management system.
The speedometer is based on a BananaPro embedded ARM board which is based on a pretty powerful Allwinner A20. Currently the graphics are rendered by software rendering, but it is planned to use the OpenGL ES capable graphics unit to render it. This should speed up the rendering from 10fps to about 30-40fps.
In the background there is a thread which stores all measured values to a database to use the data for a scientific cell model. Maybe I will use this model to calculate the SoC (State of Charge) and SoH (State of Health) of the cells in the future.
Prior starting the project, I have shot some images of the CityEL to show you the state before. I try to document every step with at least some images.
I have unmounted the roof, as I will mount a new one. It is too complicated to repair the roof. I would need to glue the polycarbonate with a special glue which would be visible. So I have chosen a glas fiber reinforced roof manufactured in the Czech Republic.
I have started working on an additional project. It is all about a battery electric vehicle, specifically a CityEL built 1991.