[FAQ] Cell Balancing FAQs

What type of cell balancing does the BQ79616 perform?

The BQ79616 does passive cell balancing. This means the excess charge from cells that have a higher charge is expended through resistors. This is to ensure that all cells have an approximately equivalent SOC (state of charge).

How is the cell balancing in the BQ79616 “autonomous”?

The BQ79616 can autonomously switch between even and odd cells at different stop conditions. These intervals are chosen and set by the customer beforehand. The stop condition is a set timer (up to 10 hrs) and a cell voltage threshold (whichever comes first). There is also a thermal stop condition. 

Alternatively, manual cell balancing control can be used to have more control over which channels are enabled (each cell can be set to have a different balancing time), but the stop conditions are still timers and cell voltage threshold. There is also a thermal stop condition. 

If the cell balancing is running, the MCU can read out the remaining balancing time.

What are the capacitors on the cell balancing inputs for?

These capacitors are part of the filters that are necessary for proper hotplug performance. They should not be removed. They can be reduced to 4.7 nF.

Is there a model to help simulate the external balancing circuitry?

Yes, this can be found here: /cfs-file/__key/communityserver-discussions-components-files/196/External-CB-FET-Solution.TSC