• State Resolved
  • Locked Locked
  • Replies 2 replies
  • Subscribers 63 subscribers
  • Views 247 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.

Getting started questions for BQ34Z100EVM

Dale Wityshyn
Prodigy 20 points
Other Parts Discussed in Thread: BQ34Z100, BQ34Z100EVM

I am considering using the BQ34Z100 to monitor a 48V LiFePo4 pack used for an electric bicycle. 

I have purchased a BQ34Z100EVM and EV2300 and the time has come to open them up.
I have a couple of questions before I get started.
1. The EVM specs say that the board should not be subjected to more than 50V, yet the nominal voltage of my "48V" pack (16s, I believe) is slightly higher. Will I likely be OK or do i need to adjust the voltage divider on the EVM?
2. The EVM specs limit the current to 7A. My application routinely sees currents of 25A or more. Would it be acceptable to replace the on board shunt with an off board one that can handle the increase in power?
3. This is probably the most important question and possibly the dumbest. Is it absolutely necessary for this chip to be able to monitor the charge current into the battery? Is there some way to only monitor the discharge and some reset the chip to full after recharging the battery offline?
Thanks in advance for your help and patience.
Dale
  • 0
    TI__Guru 73830 points

    Dale,

    You should not apply more than 50V to the EVM with the 48V resistor divider. You can use the equation in the datasheet to resize the resistor divider for your setup. You will need to use an off-board shunt to support 25A. The connector is rated to about 6 to 8A. The Impedance Track algorithm needs to monitor charge and discharge current to work properly. If you do not let the device monitor current during the charge, then you are going to have to reset the device after charge has been completed.

    Tom

  • 0 in reply to ThomasCosby
    Prodigy 20 points

    Hi Tom,

    Thank you for answering my questions so quickly.

    Time to dig in. :-)

    Dale.