• State
  • Locked Locked
  • Replies 3 replies
  • Subscribers 65 subscribers
  • Views 789 views
  • Users 0 members are here
Support feedback
Options
Options
Similar topics

This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

bq24650 2S charging

André Silva
Prodigy 60 points
Other Parts Discussed in Thread: BQ24650

Hi Guys! I am trying to design a solar powered charger for a 2S lipo battery with the bq24650! could you give some help/advice about what components to choose? I want to charge it around 200mA...

Thanks,

AS

  • 0
    TI__Genius 13700 points

    Hello Andre,

    The schematic found on Pg. 2 of the datasheet is a great place to start.

    Some of the biggest changes will be to change the value of Rsr so that 200mA results in a 40mV voltage drop. You will also need to adjust the MPPSET voltage divider to work with the solar panel that you select.

    The table on Pg. 17 of the datasheet provides a great starting point for sizing the power components properly depending on your design.

  • 0 in reply to Ryan May
    Intellectual 280 points

    Hello Ryan,

    If I may to ask question to this subject as it is concerning solving a similar issue:

    I Am using the 24650EVM and use its factory configuration to charge 3cells of Lithium ion. as in the data sheet, the charging voltage Vbat - should be 12.6v to this configuration, in addition, we entered Vin 19.2v and Max 3.4A, the process going well - SAT 1 is lighted.

    After a 7 hours, Vout is still measured at 12.4v and SAT 1 is still lighted - the problem - it should have been changed to 12.6v and SAT2 should be lighted instead.

    the question is - why it is still on Vout 12.4v? And not changing At 12.6V as in the data sheet? Why SAT1 is still on, instead of SAT2? 

    thank you,

  • 0 in reply to or nsl
    TI__Genius 13700 points

    Hello,

    The most likely reason for why the output voltage is 12.4V instead of 12.6 is a result of the voltage divider produced by R13 and R15 on the EVM. There resistors while they are precise still have a 1% tolerance which could be why the voltage is a little off. Have you measured the resistance values in this divider and calculated what the expected output voltage should be?


    What is the size of your battery and the current that you are charging it at? Also do you have termination enabled and if so what is your termination current. It is possible that even though it was charging for so long and was at the regulation voltage that the current taper had not completed or termination might have been disabled.