Wrong readings with MAX17043

Hi All,

I'm using a MAX17043 to monitor the SOC of a 18650 2900 mAh for a small weather station (equipped with an ESP8266 nodemcu).
The MAX17043 board seems a clone of the Sparkfun one, its I2C address is 0x76.
I can connect and receive data from the board but:

  • voltage of the battery is 3.932 (with a multimeter), the MAX17043 reading is 2.218 V
  • SOC is 0.00 even after 30 minutes of monitoring
  • compensation value is 0x97

then the communication is taking place, but I can't explane why all that difference between multimeter and MAX17043 reading...and why the SOC is 0.00 while the battery is charged.
At the moment it's powering the weather station and the INA219 sensor connected to the battery is reading "3.924 V".
To test the board I've used the library of Daniel Porrey changing the I2C_ADDRESS to 0x76.
Any advice? (other than "buy the Sparkfun board" :stuck_out_tongue_closed_eyes:)
Thank you, regards.


I would suggest you include a schematic, not a frizzy thing. The address is generated by the MAX17043. Show how you connected the grounds and your voltage reference point. Include links to the modules you used.

The module is the following:


I attached the scheme used to test the board, I left the VCC pin of the board unconnected but also if connected to a 3V3 pin of the ESP8266 nothing changed.


Are you sure you have the correct pins for SDA/SCL on that “ drawing”??

Yes I'm....SCL is pin D1 on the ESP8266, SDA is D2 and according to the serigraphy printed on the back of the board the connections are correct.
Have you noticed something wrong that I can't see? :o

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