SparkFun Fuel Gauge with MCP73871

Components & Accessories Power
1

Hello, is it possible to use the SparkFun Fuel Gauge (MAX17043G+U) with battery charger MCP73871 (diymore board more specifically)? I’m having a hard time to make these two work together since whenever I connect the battery, the MCP board instantly overheats and the LiPo battery dies. I’m almost sure that the connections are all properly made. Below are some details of the complete circuit:

  • Battery: LiPo 3.7V, 1200mAh
  • Battery management: MCP73871
  • Fuel Gauge: SparkFun MAX17043
  • Booster Step-up: MT3608
  • MCU: Arduino MEGA 2560

The idea is to be able to power up the MCU with the battery and get the state of charge from the fuel gauge. I’m using the MCP73871 because I want the possibility of using the equipment while charging the battery (the MCP does that well with the built-in load sharing system).

Here is how everything is connected:

  • Battery JST -----------> Fuel Gauge JST female
  • Fuel Gauge (+) --------> MCP73871 BATT
  • Fuel Gauge (-) ---------> MCP73871 GND
  • Fuel Gauge Vcc -----> MCU 5V
  • Fuel Gauge GND —> MCU GND
  • Fuel Gauge SDA ----> MCU SDA
  • Fuel Guage SCL -----> MCU SCL
  • MCP73871 LOAD —> MT3608 Vin(+)
  • MCP73871 GND ----> MT3608 Vin(-)
  • MT3608 Vout(+) ------> MCU 5V
  • MT3608 Vout(-) -------> MCU GND

PS: the output filter capacitor that comes with the MCP73871 diymore board is connected as recommended in the datasheet.

Simple image of the connections:

circuit
circuit773×502 8.61 KB

2

You either have a bad board or you’re battery polarity is incorrect.

The MAX17043 is 4.5 volts absolute max, hopefully the 5 volts didn’t fry it. If it did, you will need to replace that and connect it to 3.3 volt power instead.

2 Likes
3

It was the polarity indeed. The JST connector from the battery had its polarity inverted. Red wire was going to the negative on the Fuel Gauge, and the black one going to the positive. Thanks for the help.