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Original question:

BQ40Z80EVM-020: Timeout/failed to communicate/wrong value

BQ40Z80EVM-020: BQ40Z80: Timeout/failed to communicate/wrong value

Zeev Guzman
Prodigy 40 points
Part Number: BQ40Z80EVM-020
Other Parts Discussed in Thread: BQ40Z80

Tool/software:

Hello,

like in the previous case ( e2e.ti.com/.../bq40z80evm-020-timeout-failed-to-communicate-wrong-value ), sometimes (about 2..3 cases out of 10 batteries), after connecting the BQ40Z80 to the 7S battery, there is no connection via SMBus. After disconnecting and reconnecting the battery, the SMBus connection is restored, but the Battery Management Studio screen displays a voltage of 65534 mV instead of around 25000 mV, and the contents of the data memory are unavailable. After uploading the .srec file, the BQ40Z80 functionality is restored. This is not very convenient, since we have to unsolder and solder the battery to the BMS each time. Please let me know what are the possible causes of this problem and how to avoid it? Does the order in which the wires are connected from the battery to the BMS matter (for example, first positive, then negative, or vice versa, first negative, then positive)?

Thanks in advance!

Zeev.

  • 0
    TI__Mastermind 27321 points

    Hello,
    The bq40z80 is not longer supported in 7S mode. It is known that it can cause issues if used in 7S mode. This is why we do not longer have this device listed as 7S device.

  • 0 in reply to Jose Couso
    Prodigy 40 points

    Hello Jose,

    when BQ40Z80 was still listed as 7S device, we have developed 7S Li-Ion battery with BMS based on BQ40Z80. We've been producing several dozens of such batteries every month. If you discontinue support for 7S mode, we will have big problems with producing these batteries. What exactly is the technical essence of the problems that caused you to stop supporting BQ40Z80 in 7S mode? How critical are they, and how do these problems affect the BMS functions? If BQ40Z80 can no longer be used in 7S mode, what are the replacement options?

  • 0 in reply to Zeev Guzman
    TI__Mastermind 27321 points

    Hi Zeev,
    For customers that already have been using them and are at the production level, we might help debug issues. 

    I cannot reveal TI proprietary information in the public forum. Please contact your local FAE and have him/her reach to us.