• State Resolved
  • Locked Locked
  • Replies 3 replies
  • Subscribers 62 subscribers
  • Views 586 views
  • Users 0 members are here
Support feedback
Options
Options
Related

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.

Help choosing IC for battery charge/discharge application

Hau Tran
Intellectual 615 points

Other Parts Discussed in Thread: BQ24610, BQ24773, BQ24170, BQ25703A

Hello all,

I am new to battery technology and I am building an application with such requirement.

We will be using 3S 18650 Li-ion batteries to power a motor. So it then will be charged/monitored when the motor is not running, when the motor is running, the battery will not be charged. Which ICs should I be looking into to achieve such requirement? How can I prolong the life of battery in such application?

There are two options of power supply (12V/5A or 15V/4A) that I can choose to power the motor control MCU and also act as the charger adapter, which one should I choose? I assume the 15V/4A is better because the 3S charging voltage has to be greater than 12.6V since voltage of each cell is 4.2V at full charge, is that correct?.

Thanks,

Alex

  • 0
    TI__Guru 56650 points
    Tran,

    If you pick 15V input, we can use a buck charger, such as: bq24170; bq24610, bq24773..
    If you have to use both 12V and 15V input, we have to use buck and boost charger bq25703A.
    So, 15V input can simplify the charger circuit.
  • 0 in reply to Wang5577
    Intellectual 615 points
    Hi Wang,

    I have another question, if the battery is rated at 1200mAh. If I have the 3S topology, the charging current for each battery should be ~600mA to 840mA or that charging current is for the whole battery system?

    I can't quite understand how do we charge each cell and monitor them if it is in series? What ICs can I achieve this as the extended from the solutions you offered above?

    Thanks,
    Alex
  • 0 in reply to Hau Tran
    TI__Guru 56650 points
    Alex,

    When the battery cells are in series, all battery cells get same charging current. If the series cells are not same, the charging voltage or status could be different for each cell even with same charging current. In this case, we need a gauge IC to monitor and balance them. Please start a new post to ask the gauge IC question and put it in gauge forum.