Hi,
I’m seeking advice on selecting the appropriate battery monitoring IC for a project involving a 4S LiFePO4 battery pack. My key requirements are:
Accurate Cell Voltage Monitoring: I need to measure individual cell voltages in a series-connected pack.
Open-Wire Detection: The system should reliably detect when a cell is physically disconnected (i.e., reading 0V or open-circuit conditions).
Handling Removed Cells: The IC should continue monitoring the remaining cells accurately, even if one or more cells are removed from the stack.
I initially started using precision rail-to-rail op-amps configured as differential amplifiers to measure cell voltages. However, handling floating inputs when cells are removed from the stack altogether has proven to be a non-trivial design challenge. To simplify the design, I’m considering dedicated battery monitoring ICs for voltage readings and open-wire detection, with the L99BM114 as a potential candidate.
That said, I’m concerned about the L99BM114’s open-wire detection capabilities. The datasheet states:
"This safety mechanism is also able to detect loss of cell PCB connector. In fact, if Celln positive terminal is disconnected from PCB, both BALn_OPEN and BALn+1_OPEN failures will be flagged. Two exceptions: • If PCB connector to cell14 positive terminal (C14) is lost, only BAL14_OPEN flag will be set • If PCB connector to cell1 negative terminal (C0), CELL0_OPEN flag will be set."
Does this mean that I can still accurately measure the remaining connected cells when one cell is physically removed from the pack? And if cell 2-13 are removed then the flags for all higher cells in the stack will also be set?
Is there any alternatives you could reccomend otherwise? Additionally, any insights on configuring the ICs to handle open-wire detection and removable cells would be greatly appreciated.
Thanks
