Other Parts Discussed in Thread: BQ40Z50, , BQSTUDIO, BQ24800
I'm designing a UPS power supply, with a pack of 2S LiFePO4 cells (7.4V max - 5V min) and bq40z50 as BMS. I need VSYS to be always regulated at 12V and 2A max current on backup.
I bought BQ24800EVM and made some tests with this board, it all works as expected except when I try to enter backup with VBAT below 5.5V, or switch from loaded VSYS at 2A to battery backup with less than this voltage on VBAT. I would like to lower this threshold as I may want to discharge my cells some more, and let the bq40z50 decide when to stop.
My settings are:
- Charge Voltage: 7440mV
- Battery depletion comparator threshold: Failing Threshold 59.19% ~2.486V/Cell (this means around 4.4V minimun voltage on the battery right?)
- Battery boost regulation voltage: VSysMin + 1.6V
- Minimun system voltage: 10496 mV
I don't know if this could be modified or if it's a restriction of the IC as I don't have the datasheet yet, I'm waiting for approval.