come on guys, the current generation MacBooks charge off USB-C ports. and yes, USB battery packs won't be powerful enough to 'charge' the battery, but they will be enough to power the MacBooks, at least during light-to-average usage. so yeah, when you are low on battery, just plug it into a battery pack, or any usb charger, it will last on you. what? you edit 4k videos on the go constantly? and you are talking about battery life?