TP4056 read solar input and batterystatus

Hi there,
I'm pretty new into this world and I'm trying to build a very nice solar weather station.
For now i have some sensors connected to a WEMOS pro D1 mini which is working fine with a LUM sensor and a BMP280 sensor.

Since the whole setup is powered by a battery trough a TP4056 module and charged by a solar panel i want to know if the solar is providing power and how much it is. Beside that i also want to know the battery status, how much power is left in de battery.

Is there a way to achieve my goal?


Battery voltage is easy, and the only relevant thing.

Connect a 100k resistor between battery(+) and A0, and get it’s analogue value.
With 100k in series with the onboard divider, 4.2volt should return an A/D value of 1023.

Hello Leo,

You mean the A0 of the Wemos? And is there a way to know if the solar is giving some power? Is it the same trick to put a resistor on the + solar side to A0?

I want to know how much the panel is supplying to the battery.

The WeMos has only one analogue (voltage) input.

An INA219 breakout board (I2C) might be ok if you also want to know solar voltage/current.
This is ofcourse an extra drain on the battery.

This weather station from PaulRB (member here) might be an interesting read.

Hello Leo, thank you, ive read PaulRB's article.