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BQ34110: Bq34110

vani katta
Prodigy 60 points
Part Number: BQ34110
Other Parts Discussed in Thread: BQ34Z100EVM, BQ34Z100,

Dear Sir,

We would like ti use BQ34110 for Battery Health Monitoring System project. we would like to measure individual lead acid battery voltage and temperature and battery bank current,voltage and temperature.

my query : can we able to measure individual battery temperature with only voltage input (without current )  or else we need to use external thermistor .

we have to use it for measuring battery temperature , then we cannot able to use thermistor AT103-2 . can we able to use RTD's , Thermocouples externally to measure individual battery temperature.

9

Secondly : the required currents to be measured are above 50 Amps upto 1200Amps . How to scale down the currents to be measured . because the limitation of bq34110 if upto 32A  .it is mentioned in datasheet that beyond these range , we need to scale down.

kindly help us in this regards.

awaiting for your early and valuable response,

Regards,

vani.K,

Hyderabad,India

  • 0
    TI__Guru* 76230 points
    Hi Vani,

    -If you are trying to measure individual battery temp you will have to do that using your host controller and a thermocouple or thermistors or what ever means you chose, this will be totally independent of the gauge. If you decide to use the gauge external thermistor, you just need to place it close to your battery pack.

    - For currents greater than that 32A, you will have to scale. Pls refer to app note below to act as a guide.

    www.ti.com/.../slua760.pdf

    thanks
    Onyx
  • 0
    Prodigy 50 points

    Dear TI Team,

     

    Thanks for suggestion, we are planning to use one dedicated device for measuring overall Battery Bank Current by scaling down as per app note shared.

     

    Further wants measure Voltage and temperature of individual battery,

     

    Request your clarification on making use of Precision Coulomb Counter, Voltage, and Temperature Measurement (both) .

    We do not want use external temp sensors to avoid wiring from Battery to Control card.  if can make use of internal ADC and sensor for temp measurement along with voltage, it could be great design and can avoid external temp sensor for each battery.  Request clarification and share and ref design on this.

     

     

  • 0 in reply to BS Rao
    TI__Guru* 76230 points
    Hi Bs,
    Pls refer to the user guide on ti.com of the device for schematic diagram and layout. There are instructions there on using the gauge.
    thanks
    Onyx
  • 0 in reply to Onyx Ahiakwo
    Prodigy 60 points

    Dear Sir,

    We have purchased BQ34z100evm for lead acid chemistry battery management system.

    we have query , whether can we use BQ34Z100 for lead acid battery management system . i.e multi chemistry.

    Regards,

    Vani.Katta

  • 0 in reply to Onyx Ahiakwo
    Prodigy 60 points
    Dear Sir,

    We are using bq34110evm-796 evaluation board . as per instructions we have tested using 2Amp load.
    for 25amp load what changes we have to carry out in evaluation board .
    because for more that 2amp , resistor R21 got heat up.

    awaiting for your valuable suggestions,
    Regards,
    Vani.K
  • 0 in reply to vani katta
    Expert 2475 points

    The bq34110EVM can support about 2A continuous current and up to about 7A pulsed current. If you need to support higher current requirements, then you can remove R18 from the EVM and use an external sense resistor. You can use a twisted pair wire to connect the sense resistor to J7 on the EVM. A twisted pair wiring harness will be required to improve noise immunity. You can use current scaling in the document that Onyx provided to support the load current above 32A.

  • 0 in reply to TEC
    Prodigy 60 points

    Dear Sir,

    For 20 to 30 amp how much sense resistor we have to use and where to connect. please tell us the connection point in BQ34110evm-796. please tell the calculation formula.

    Do we need to use dc shunt upto 30Amp or simple chip resistor 1W will serve the purpose.

    Regards,

    Vani.K

  • 0 in reply to vani katta
    Expert 2475 points
    The voltage drop across the SRN / SRP interface should not exceed +/- 125mV, so the sense resistor will need to be 4 mohm or lower. If you were to use a 4 mohm sense resistor, then the power dissipation at 30A will be 3.6W. You can buy sense resistors to support this.