woah there, if its a regulated 5 volt output then nothing will be in danger of being fried. and i think the conversion in mAh comes from the boost converter. to get 5 volts from 3.whatever you need to drop the current capacity, so more amp draw on the battery in exchange for more voltage. so long as the energy is the same (minus conversion losses) it works out.
[edit: the input of 400mAh makes no sense however]
Thanks. I think the Input might have to do with it being Charged by USB or by the Solar Panel.