We're Monitoring You
As mentioned previously, careless treatment of the Tesla battery modules can be catastrophic, leading to fire or other failure. Therefore, it is important to monitor the state of the cells to assure they are in proper temperature and charge or discharge. To do this, a Battery Management System (BMS) is required. I'm using the popular Orion BMS 2. The BMS protects and monitors a battery pack by monitoring several sensors and using several outputs to control charge and discharge into the battery. The BMS measures inputs from cell voltage taps, a hall effect current sensor, and thermistors. Using the programmed settings, the BMS then controls the flow of current into and out of the battery pack by broadcasting charge and discharge current limits via the CANBUS to the OnBoard Charger (OBC). During and immediately after charging, the BMS will balance the cells using internal shunt resistors based on the programmed settings.