Hellos.
Is it possible to monitor the charge level from the powerbank i have connect to an esp8266?
No.
At least, not easily. The power bank is going to output more or less a constant 5V until it runs out of energy, so you won’t be able to detect based on output voltage.
You’re going to have to do some soldering, and maybe even math too.
- You might be able to use a power meter chip like the INA219 to measure voltage, current, and power, then integrate those to figure out how many Wh of energy have been put into or extracted from the battery.
- You might be able to find some sort of lithium battery fuel gauge chip that does that for you.
- You might be able to make a high impedance voltage divider to scale the battery voltage into something the ESP8266 ADC can accept, and use that to approximate the charge state.
- You might be able to approximate the signal you’re looking for by somehow monitoring the status LEDs if they exist.