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BQ25890EVM-664: charge and balance four 64 volt solid state battery

freidoon Rastegar
Prodigy 10 points

Part Number: BQ25890EVM-664
Other Parts Discussed in Thread: BQ25890, BQ25750, BQ79616, BQ25751EVM, BQ25751

i have this board BQ25890,

  1. i have not been able to slow charge our solid state battery slowly and also the log does not dispaly voltage or current. The Bq studio show fast charginging and  but it display this binary 6,2025-11-27 17:46:27,24.053,40,06,50,00,0A,01,68,89,00,00,73,06,00,13,5A,5C,51,99,00,00,1D,331,SUCCESS   which converted does not matchmeasured ampmeter and Voltage.     
  2.  please help me  to identify a product that can charge a pack of 67 volts (80 Ah).  

regards 

freidoon@ssbats.com

 Solid state battery

3107536769

  • 0
    TI__Guru**** 175966 points

    Hi Freidoon,

    BQ25890 is a single cell, up to 4.35V battery charger.  Did you mean a higher voltage charger like BQ25750, up to 70V charger? 

    Regards,

    Jeff

  • 0 in reply to Jeff F
    Prodigy 10 points

    understood , i asked two questions   1.  how do i convert the Log to voltage  and current on BQ2590VEM (which binary no is Voltage and which on is  the current and what are the conversion equ ie v=2.34 * d +T etc)   2, we have four  single bipolar at 80 amp 70 VDC i selected 

    BQ79616 for balance and 

    BQ25751EVM for charging, not sure I will need a voltage divider ....   am I way off?

  • 0 in reply to freidoon Rastegar
    TI__Guru**** 175966 points

    Hi Freidoon,

    I assume you are referring to the ADC values?  If so, then for voltage, 2.304V+20mV*reg_value_decimal.

    If the solid state battery has the same charge profile as lead acid battery, then BQ25751 is a choice.

    I do not support the BQ79616 so I recommend creating a new post with that part number so that the appropriate TI group can respond.

    Regards,

    Jeff

  • 0 in reply to Jeff F
    Prodigy 10 points

    Hi jeff   Yes I am trying to figure which value is output voltage and current on ADC log   I see "ADC_Charge_Current_conversion" and "VBUS_status__and_ADC_VBUS_Voltage_conversion"    I sure which on is  out put voltage and current .. LOL here i sthe entire header . sorry for the long note   thanks again  Regards                                   DateTime,ElapsedTime,Input_Current_Limit__HIZ_and_ILIM_pin,OTG_Temperature_thresholds__and_Input_Voltage_DPM_Offset,ADC_controls__OTG_Frequency__ICO__DCP__and_Input_Detection,Battery_Load__WDT_Reset_periods__OTG_and_Charge_Enable__and_MINSYS_setting,Fast_Charge_Current_Limit_settings_and_MTK_Pump_enable,Pre-charge_and_Termination_Current_Limit_settings,Charge_Voltage_Regulation_Limit__Battery_Low_Voltage_and_Recharge_threshold,Termination_Current_Enable__STAT_pin__WDT__Safety_Timer__and_JEITA_Charge_Current,IR_Compensation_and_Thermal_Regulation_thresholds,ICO__Extended_Safety_Timer__BATFET_control__MTK_Pump_Voltage__and_JEITA_Charge_Voltage,OTG_Regulation_Voltage_and_Current_Limit_settings,Charger_VBUS__Charging_Mode__PG__USB_Input__and_System_Voltage_Regulation_status,WDT__OTG/VBUS_OVP__Thermal_Shutdown__Safety_Timer__and_TS_pin_faults,Input_Voltage_DPM_settings,Thermal_Regulation_Charge_Status__and_ADC_Battery_Voltage_conversion,ADC_System_Voltage_conversion,ADC_TS_pin_voltage_as_percentage_of_REGN_conversion,VBUS_status__and_ADC_VBUS_Voltage_conversion,ADC_Charge_Current_conversion,DPM_status__and_Input_Current_Limit_setting,Registers_reset__Input_Current_Optimizer_status__Device_ID__and_Temperature_Profile,LogRowTime(ms),LogStatus

  • 0 in reply to freidoon Rastegar
    TI__Guru**** 175966 points

    Hi Freidoon,

    The equation I gave is for ADC_Battery_Voltage_conversion.  The 20mV is the resolution in the spec table. 

    The others follow the same general formula except TS pin voltage.  The app note below helps with converter TS pin voltage to battery temperature.  https://www.ti.com/lit/pdf/slua745.

    Regards,

    Jeff

  • +1 in reply to Jeff F
    Prodigy 10 points

    thanks   i am still not clear which log parameter is the actual voltage  or current..  Thanks anyway

    regards