Hi Folks,
I'm creating an arduino project based on Nano 33 Iot to measure the voltage of batteries (max voltage 3.6) theese are elements of a LiFePO4 battery for a Camper, due to the charging circuits (including car alternator) I run the risk of damaging the Arduino analog ports, for this reason I'm adding:
a voltage divider (simple resistors) to reduce the voltage range between 0 and 2.9v (2.9 for specific design need)
a Zener (voltage 3 volts) to avoid exceeding the 3.3 volts of analog ports
a schottky to avoid negative voltage
a capacitor to cut high frequency (voltage should change very slowly)
Based on your experience, do you think this is sufficent ? if not could you provide suggestions ?
What is the best value of the capacitor?
The circuit:
Hi,
sorry for being late,. @DVDdoug : you are rigth I'm atting below the full picture (still WIP).
The idea is to have 8 opamps do measure the voltage of each cell (between 2.5 and 3.65volts), use an analog multiplexer as I will need more ports on arduino for other porpuses. FInally I'm amplifing the signal to have a wider range of voltages.
Are there any parts of the circuit you haven't shown? What is the op amp ground reference? Have you built any prototype yet? The final op amp is a complete waste, it has unity gain. Also you're running it into low impedances, it will go into current limiting...
