How to measure the battery while it is charged?

Hello,

I want to measure the charge of a rechargeable 48v, while it is charging. I searched the internet found nothing like that. How will the circuit to monitor the battery charge level while it's charging?

Measure the voltage on the battery through an appropriate resistor divider (ie, like a 15:1 divider or something), and measure that with the ADC.

You'll need to look at behavior of the charging battery when the charging voltage is removed, as of course the voltage jumps down to a new voltage, even though this doesn't represent any change in state of charge.

If you want to measure it with an UNO, use a 10 to 1 resistor ladder circuit connected to an analog input.

Input 48V -------- 8.2K ------- 2K POT \/\/\/\/\/  -------GND
                                          |
                                          -------- analog input

Adjust pot for 4.8 volts with 48V at the input.

Write your Sketch to read the voltage.