• State TI Thinks Resolved
  • Locked Locked
  • Replies 1 reply
  • Answers 1 answer
  • Subscribers 63 subscribers
  • Views 339 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.

BQ34110: using EOS_RCELL_RRATE_LEARN()

Mark Scovel
Intellectual 595 points
Part Number: BQ34110

We imagine we are going to turn off EOS' auto learn feature (Auto Learn Time set = 0) and initiate EOS periodically (perhaps daily) during float voltage mode once current drops below ~45 mA. If we do that, EOS will not be able to auto learn the initial rcell value (captured when the battery was first put into service). So, we plan to manually initiate Rcell/RRate learning via EOS_RCELL_RRATE_LEARN. But if we initiate Rcell/RRate learning periodically, won't that cause Rcell/RRate re-learning which will defeat the ability of EOS to determine end of life? Does that mean we need a mechanism to know that we've already completed manual Rcell/RRate learning on a particular product and NEVER do it again? And what happens if a service person replaces the batteries in a fielded product? Do we need to re-initiate Rcell/RRate at that time?

  • 0
    TI__Expert 5090 points
    Hi Mark,

    The device has a DF that tells whether the Initial Rcell has been captured or not. If not, then the command will measure Rcell and store it as the Initial Rcell. If it has already been captured, then it is assuming a new Rcell is being captured, this will then be compared to the Initial Rcell.

    I would recommend you don't use the Rrate functionality (RSD), just stick with the DRD method. For DRD, you can measure Rcell often, and the device will compare the new readings with the stored Initial Rcell. However, the Rrate is looking at the difference between consecutive Rcell measurements over time, and if you take measurements too close together in time, you will find that the noise in the measurement will cause the rate to jump around a lot (since the Rcell won't have changed much over the course of a day, for example). If using RSD, you probably should not take readings more than once every several weeks to a month (after some moderate aging has likely occurred), but this will take some experimentation to understand how often is too often, based on the rate your cells are aging.

    Thanks,

    Terry