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BQ24650: bq24650

Part Number: BQ24650

Hi Team,

one of my customer facing the issue in bq24650 Synchronous Switch-Mode Battery Charge Controller, in which the charge controller waits for 30 min for the Vfb pin to go above 1.55 V .If the voltage does not reach 1.55 V at Vfb pin charge will be terminated and they have to reset the input manually .As they are using this IC in Solar street light reinitiating charge manually is not suggested .So in this scenario the charger IC will fail to charge the battery and the device will not work.

Kindly advice on this.

  • Hi Yashwitha,

       This is the inbuilt precharge safety timer of the BQ24650, which is fixed at 30 minutes and cannot be configured. If battery voltage (on VFB) does not rise above VLOWV (1.55V) in 30 minutes than charger will stop charging and indicate a fault. To reset the safety timer, and initiate a new timer, you can toggle the MPPSET pin low. You can also try increasing precharge current so battery can reach VLOWV but this would also increase the charge current in BQ24650.

  • Hi Kedar,

    We are using Li-ion Battery pack in solar street light application (operating voltage is 12V to 16.4V). When the battery voltage is below 11V and low sun intensity during early morning time. During this condition charge controller BQ24650 is unable to supply required power to reach 12V within 30 minutes pre-chargin time.  Charge controller will terminate pre-charging. Note: It difficult for the user to reset the device 

    VFB pin needs to be configure between 1.54V (Low) to 2.1V (High) and there is constraint that voltage divider values will not match with these voltage  and  it should be within operating voltage i.e 12V to 16.4V. 

    Please suggest us solution

    Regards

    Gururaja K

  • Hi Gururaja,

       I answered this post on your original post. Thanks!