Part Number:BQ4050
I'm designing a BMS for 4S 5200mAh Li-Po battery pack, discharge current is up to 50A, currently i chose BQ76920 in companion with BQ78350-R1.
The BQ78350-R1 datasheet (SLUUBD3C–September 2015–Revised October 2016) said that cell balancing occurs only when charging.
Since the charge time is around 50-70 minutes (1C), balancing current need to be around 250-300mA to bring the pack balanced at full charge (Based on less than 5% imbalance in SOC), which is slightly high and lead to design issues. (eg. large dissipation resister).
So i'm looking for a more suitable solution and found that BQ4050 provides balancing while charging or at rest, my battery is designed for drones, the battery will be at rest most of the time, balancing cell at rest could reduce balancing current since the BMS has more time to balance the cell.
I'm confused with a recently downloaded BQ4050 Tecnical Reference (SLUUAQ3–March 2016), on page 51, it said that Cell balancing only occurs when charging current is detected, which is different from it's data sheet (SLUSC67B –MARCH 2016–REVISED OCTOBER 2017) that said it can do balancing while charging or at rest.
In conclusion, please clarify the questions below.
1. Is BQ78350-R1 (in companion with BQ76920) support cell balancing at rest?
2. Is BQ4050 support cell balancing at rest?
3. Any suggestion would be appreciated (in design, better solution, useful articles, etc.).
Thanks.