MCP73844 - Battery pack not charging fully

The following are some reasons why a battery pack is not charging fully:

  • The MOSFET could be overheating resulting in the battery not charging to its full capacity.
  • The battery pack could be faulty. To test if the problem is with the battery or the circuit: Apply a very low current (100 mA - constant current) to the MOSFET, and input the voltage as per specifications. Observe the battery voltage, if it is slowly rising then you can increase the current in steps up to about 1 A (double check that the battery you are using can handle 1 A current) and observe the battery voltage. If the battery voltage reaches full capacity then you can conclude that the battery is working properly.
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