Hi,
Notes on charging your MacBook Pro:
- Your MacBook Pro draws power from only one power supply, even if more than one is attached—so using multiple power supplies will not speed up charging.
- If you connect multiple power supplies to your MacBook Pro, the one that provides the most power will be used, regardless of the order in which you connected them.
- You should not connect any power supply that exceeds 100W, as it might damage your Mac.
- Using a power supply that doesn't provide sufficient power can result in slow or delayed charging. It's best to use the power supply that came with your Mac.
The notes above are presented as fact from an Apple document for the new MacBook Pros, so, it will only charge from one, it won't charge faster, and it won't catch fire.