Hey, I'm currently working on a car battery (12V lead acid battery) monitoring system that I plan on making into a PCB design. I'm currently researching ways I will measure voltage and they simplest way I feel is a voltage divider. The arduino will be powered off a seperate battery and I'd like th…

Automotive electrical circuits are extremely noisy and hazardous to electronics. You will need protection against high voltage spikes, electrical noise and voltage reversals. There is plenty of design information online, for example Transient Voltage Suppression in Automotive Applications

LED volt meters are available for the price of a cup of coffee. Leo..

You can add a protection diodes to your voltage divider. Or, the AVR chip (Arduino Uno, etc.) actually has small (low current) diodes already built-in and if your voltage divider resistors are in the ballpark of 10K, that limits the current and the built-in diodes can probably handle it. I have a…

Personally first I would heed the advice of jremington's post. Then I would likely take the divider route. Finally I would do as Wawa suggested which is what I did on an old car I had. Unless you plan to do something with the voltage readings a DC voltmeter can be had off the shelf for less than you…

[image] DVDdoug: You can add a protection diodes to your voltage divider. First answer, second example is excellent.

I've used this, others would probably suggest some changes. I was using a Mega2560, so 5v input on the Arduino pins - adjust the divider resistor values if your Arduino does 3.3v One important thing to note is I use a separate regulated +5vdc supply for sensors and similar, which those schottky pro…

Using an Arduino to Measure voltage of a 12V Car Battery

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Paul_KD7HB September 23, 2023, 9:23pm 6

Be especially aware of your ground or negative connection. If the car ground opens up all the current will go through YOUR ground connection. Fuses for both + and - are necessary.

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Using an Arduino to Measure voltage of a 12V Car Battery

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