Protecting Arduino Nano Analog ports

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:


That should be fine.

Protection Circuits

To be 100% sure of the answers here, post the entire circuit. You don't show the voltage divider...

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.

The circuit:

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...

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