I'm looking into developing a small scale lead acid battery management system using the bq34z110 gas gauge with the bq77910A cell balancing and protection chip as recommended in the datasheet for the 110. The issue I'm running into is using the 77910A for lead acid battery multicell management.
I'm using four 6 V SLA batteries in series, producing 24 V total, which won't overload the 77910A. The problem which I'm facing is the issue of programming the CBV, which I'm assuming is the threshold voltage that triggers the cell balancing function to begin. In the datasheet, it shows that the threshold voltage is only programmable up to 3.9 V. This works for the lithium ion/polymer batteries with which I'm also working but would deep discharge the 6 V SLA batteries. Is there a way to program or stack the chip to get a CBV of ~5.7 V - ~6 V?
I would think this would be possible since this chip and the 77908 are recommended for use with the 110, despite their lithium ion programming.
Thank you,
Reba Liggett