New Year
Posted by Brian on Monday, January 24, 2011
Happy New Year fellow EVers,
Things have been slow and cold lately in Toronto. Cold being the key word there. Without heated facilities, we haven't spent much time with the 944. I just bought a small heater, and insulated coveralls, so perhaps I can get some work done in the near future.
We're currently working on making the BMS system operate remotely from the batteries. Our BMS design currently uses a resistive bypass circuit on each cell that can be switched on during charging to prevent overcharge. This design is inherently inefficient, and produces a lot of heat. Because of the limited spacing of our battery cells, we were worried that the hot resistors were too close to the adjacent batteries, when the BMS was mounted directly on the cells. We are going to remotely mount the BMS inside the cabin of the car, where we can more easily monitor the cell voltages, as well as properly mediate the heat produced while charging.
We completed the wiring with all of the terminals including a plug between BMS and battery in case the batteries need to be removed/replaced. When the first battery was plugged in, we had a malfunction in the BMS. We tried a second BMS board, and it didn't work either.... Needless to say, I'll be spending some time re-testing and debugging all of the boards...again...
Stay warm!
Things have been slow and cold lately in Toronto. Cold being the key word there. Without heated facilities, we haven't spent much time with the 944. I just bought a small heater, and insulated coveralls, so perhaps I can get some work done in the near future.
We're currently working on making the BMS system operate remotely from the batteries. Our BMS design currently uses a resistive bypass circuit on each cell that can be switched on during charging to prevent overcharge. This design is inherently inefficient, and produces a lot of heat. Because of the limited spacing of our battery cells, we were worried that the hot resistors were too close to the adjacent batteries, when the BMS was mounted directly on the cells. We are going to remotely mount the BMS inside the cabin of the car, where we can more easily monitor the cell voltages, as well as properly mediate the heat produced while charging.
We completed the wiring with all of the terminals including a plug between BMS and battery in case the batteries need to be removed/replaced. When the first battery was plugged in, we had a malfunction in the BMS. We tried a second BMS board, and it didn't work either.... Needless to say, I'll be spending some time re-testing and debugging all of the boards...again...
Stay warm!