Hi and thanks for your reply. I'm full aware of what you are saying. But in my application the charging circuit cannot be connected to the batteries during the time they are being used. This is an absolute requirement. So existing BMS ICs or circuits are of little help. I'm looking for another...
I have a bit unusual requirement regarding predicting appropriate time for replacing Li-Ion batteries.
In my application I will use two Li-Ion 18650 batteries (certified capacity 3300mAh) in series that will supply power to a device that draws almost constant 80mA (can vary between 70-90mA)...