Power Raspberry Pi and charge Adafruit FONA from same source

Question

I have 12v leisure batteries hooked up to solar panels, I want to be able to power my pi (5V 0.7A max) and charge the Lipo battery for the Adafruit FONA (5V 2A max) for a combined 2.7A max (i think) from the same 5V 3A step down buck converter. Does this make sense and should it work?

Answer 1

This does make sense and should work as long as you make sure your RPi really doesn't consume more than 1A. In practice that means not plugging anything power-hungry in its USB sockets and not drawing significant current from GPIO.