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BQ34Z100-G1: Batch measurements of cell strings of lead acid battery?

Marcel Hecko
Prodigy 80 points
Part Number: BQ34Z100-G1
Other Parts Discussed in Thread: BQ34Z100

Im wondering whether I can use bq34z100-g1to monitor a substring of 200V lead acid battery which has 6V cells without actually putting any resistor in series with the cells. 

My goal is to measure health of the cell(s) by connecting the sense resistor in paralell to the measured cell (lets say one 6V cell) for a moment and then measure the internal resistaance/impedance of the cell with help of bq34z100-g1, then disconnecting the resistor from the cell again (using sir, relay or mosfet or something)

Is this simething I can use the bq34z100-g1 for? My goal really is to provide a one off measurement of the health of sections of the battery pack without the requirement to disconnect the cells to add sense resistors. 

  • 0
    TI__Mastermind 42535 points

    No, unfortunately the bq34z100 can only accept one input from your end terminals, GND and top of stack. Therefore measurements of this type cannot be done. However, if you disconnect individual packs you can measure cell resistance of each cell. Putting in a switching circuit like you suggest in your idea, you need to make sure that there's no drift in resistance due to heating of the sense resistor or of the MOSFET, secondly this can also increase your Rseries between cells and heating and therefore reduce your cell terminal voltage along with it.