LiPo cell voltage monitor ?

Other Hardware Sensors
1

Hello,

I was wondering if I can monitor voltage in one cell in my 2S 5000mAh LiPo battery using Arduino analog input.
I am not experienced in electronics (also I am Arduino newbie) so execuse me if my ideas are bad.

This is my idea of circuit

I will use analogRead and then i will double voltage of one cell to get voltage of whole battery.

I will charge my battery everytime with balancer so individual cell's voltage should be same.

Could it work ?

Thanks for any response .

2

Yes, that will work. In such situations it is a good idea to put a resistor (say 10K) in series with the analog input, to protect against accidental overvoltage or polarity reversal.

Using a 10K:10K voltage divider, you can also monitor the voltage of both cells summed.

3

You mean like this ?

4

Yes.
It also protects agains phantom powering.
Without resistor, if you turn your Arduino off, the Arduino will still be powered through the pin protection diodes.
That will drain your single cell in a few days.
When you turn the Arduino off, with a 10k resistor in series, a small current will still flow (~200uA?).
Leo..

5

Wawa:
Yes.
It also protects agains phantom powering.
Without resistor, if you turn your Arduino off, the Arduino will still be powered through the pin protection diodes.
That will drain your single cell in a few days.
When you turn the Arduino off, with a 10k resistor in series, a small current will still flow (~200uA?).
Leo..

Ok I will try it tomorrow :slight_smile: Thanks

6

Monitor the high side of the second battery through a voltage divider on a separate analogue input. It's own voltage is then the difference of the two readings.

You can't assume the second is the same as the first as their discharge characteristics are likely not the same.