So are you saying the chip would see the 12.6v?
I guess this brings up some more questions.
Can the input to these boards all use the same 5v source provided it there are enough amps?
Can I run all three outputs in parallel and then step up the 4.2v to 12v?
Here is a quick sketch I did a while back. I am trying to build a simple solar powered 18650 powered light. I have a few P channel mosfets laying around. They are not logic level. I believe they need 9v at the gate to shut off.