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BQ25504 vs BQ24210 to charge LiIon from Solar panel

Sergey Vladimirov
Expert 1300 points
Other Parts Discussed in Thread: BQ24210, BQ24650

Hi,

Id like to be able to charge 1000mA LiIon cell from 5-6V Solar panel. In the meantime it would be connected to the system that consumes 100mAh on average with peak current at startup being up to 2A.

Could you advice which of the ICs would be more suitable for me?

Thanks!

  • 0
    TI__Guru**** 151155 points

    Assuming your solar panel can provide more than 100mA at its MPP, bq24210 is the best choice.

  • 0 in reply to Jeff F
    Expert 1300 points

    Hi Jeff I guess you are thinking about 10h safety timer.

    Actually thinking to attach even 2A cell and panel will provide 100-150mA. So I guess that wouldnt work very well. The system will also require some power.

    Any other alternatives? What about bq24650?

  • 0 in reply to Sergey Vladimirov
    TI__Guru**** 151155 points

    The MPP of a 5-6V panel will be 80% of 5-6V so moving to a switcher probably won't help you much in terms of efficiency.  The bq24650 is designed for much higher power and not well suited for this application.  Besides, its MPPT function is the same as the VINDPM function on other, lower powered linear and switching chargers. 

    The bq24210 is still the best for your application. If an outside application, the 10 hour timer is likely not a concern because the timer will be reset when input power goes away. The precharge timer is the concern because the battery voltage will not increase enough on a high mAHr battery before the precharge timer expires.   If you were not planning on using the TS feature to monitor the battery's internal thermistor, then you can connect TS to VTSB to disable the timers.  If you want to use the TS feature, we should be able to use an external supervisor to drive a FET that shorts VTSB to TS only during pre-charge (i.e., when battery voltage is below VLOWV.

    If possible, I recommend a higher powered solar panel for the larger battery.