Max Current Draw

Hello,
 
Can you please let me know if I connect the SimpleRTK2B Budget board to a 5V supply and a SimpleRTK2Blite on top of it and an XBee LR radio on top of that, all 3 connected together with power being applied to SimpleRTK2B Budget board, what’s the max current it will be drawing.   I’m attaching this to my lawn mower and I’ll be converting the 12V battery to a 5V supply to power these boards, but I want to put a fuse so if the current drawn is too much, it gets shut off.
 
So can you please let me know what’s the max current it should draw for all 3 to be connected together and operate together.