How to know the battery level of my Li-ion batteries

Thread Starter

Benjamin Peere

Joined Nov 29, 2018
Hi everyone,
I have a nrf51822 Bluetooth chip that control a stepper motor, this Bluetooth chip can be powered by a maximum voltage of 3.6V, but I need a higher voltage for my stepper motor (the driver of the motor works at least with 4.5V), and as I need some autonomy and some power I use 2 Li ion batteries in series, to power my nrf51822, I use a LDO to have the good voltage and not destroy it, the thing is I would like that my nrf51822 get the battery level to know if I have to recharge the batteries or not.
Does anyone know how I can do that?
i have look for it but have absolutely no idea of how to get the battery level if I measure it at the output of the LDO, and I can't directly plug the batteries to the BLE device or it will burn obviously.

Thanks for your help, and any idea!