Smart Charger : Daughter Board


Following our smart charger project and fixing the ina3221 posts, it is now  time to do the daughter board and finish the hardware side of the project.

The daughter board is basically 3 times the following schematic :

A couple of gotcha here :

  • There is a cap somewhere on the output+ of the tp4056, so we need a pulldown resistance to discharge it. Without it,  it will take ~ 7 seconds for the battery to not be detected any longer.
  • The TP4056 goes in security mode when a new battery is connected. We have to send a VCharge pulse to make the TP4056 exit security mode. We may overdraw the power supply there, need to fix it later.
  • The TP4056x might draw a lot of current, you might experiment instability if you connect the board to your PC/Mac/Amiga for debugging purpose.  All is fine with a proper usb charger (2.1A !)

Source code is available on github.



Now time to fix the bugs and polish.



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