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BQ76PL455A-Q1: Cable length problem

Qianqian
Genius 5010 points
Part Number: BQ76PL455A-Q1


Hello TI Experts,

I am now using 7 BQ76PL455A-Q1 for  96cells BMS project,and I am confused about it really need your help:

The longest cable length between Battery and BMS(455's sense pin)  is 1.5meters

I wonder will the cable length influence the accuracy? when colletcs the votage,the current is 0 theoretically, but if the current is a very little value, it will affects the accuracy if the cable impedance is too high(Now my impedance is 800mΩ) I‘d like to know if you know the current value when colletcs the votage?

Or when I am using BQ76PL455A-Q1,can you give me any advice on the  cable length ,maybe I can follow the reuqirement.

  • 0
    TI__Mastermind 19795 points
    Hello,

    The maximum current through the VSENSE lines is 7.6 uA (see datasheet table 6.11, link: www.ti.com/.../bq76pl455a-q1.pdf). While this is very low, the accuracy can still be affected by longer cables (which will have a larger impedance as you have noted). For the impedance given, this will lead to an approximate 6.1 uV accuracy change. While this may not be too significant, I would still recommend the smallest cables you can use for your setup, as the actual impedance may be higher than desired when the various impedance sources are considered.

    Thanks,
    Vince