Hi all i need help with measuring the capacity of a Ni-Mh battery in a project, i do not know which voltage battery exactly that it will be (They use different sets from a range of (7.4v - 9.6v) the cell voltages are 1.2 volts and discharge to around 1 volt completely discharged this so i have read isn't exactly linear.
If i understand this correctly i could have the voltage range detected during power on as such:
9.6 - 8 = 8 Cell
8.4 - 7 = 7 Cell
7.4 - 6 = 6 Cell
having now known the type of battery fitted i could use a voltage divider using 2 50 ohm resistors my maximum would be 4.8 volts and minimum of 3 volts which i could measure using a analog input and convert to a battery level value.
I realize i may be understanding this all wrong so feel free to educate me i do not need to know the exact capacity more when it is getting low and needs changing to alert the user but il await your comments.
Thanks in advance, Chris.