We are developing a battery management system using the bq34z100-g1 as the basis. The chip was working fine while connected to a power supply at 5V. We were using the EV2300 to setup the flash of the chip and calibrate it.
The battery being monitored in our question is a LION battery with a capacity of ~22Ah at 24V. An external voltage divider is being used to bring the voltage down for input to the device.
To go from power supply to being powered off the battery we decided to use the power supply as a 5V source for the pull-ups on the I2C lines. The ONLY connection of the power supply at this point was a connection to the system ground and +5V on the pull-up resistors.
Upon connecting the positive and negative battery terminals the chip immediately started to draw an excessive amount of current. More specifically, we observed that the in line resistors (100ohms) on the battery ground started to heat up and smoke after ~20s of being connected.
At this point we disconnected the battery immediately and reverted the circuit to the previous state with only the power supply connected, in an attempt to assess whether we fried the chip.
Now we cannot communicate with the chip and are attempting to assess if it is something in the external circuitry or the chip itself which is fried. We have another one mounted but it is not working either. We were just wondering if anyone has had a similar experience. It was not expected that the chip would immediately start to draw an excessive amount of current from the battery after it was working completely fine while connected to the power supply.
