Maybe the answer here is just that you don't but I'm curious if anyone uses their power source for the rig to also power their laptop.
I'm trying to figure out how I would solve this and I feel like the trouble is the laptop charger wants AC while everything else works on DC. A little ironic as in the end the laptop still runs on DC. So it feels silly to have DC battery->AC->DC charger. I'm not sure how long my laptop would last on its battery alone with everything running. Maybe a little more than an hour would be possible but it seems short in AP terms.
What do you do? Do you charge it, if yes, then how? How long can you image without charging?
I'm also curious what your power situation is in general, assuming of course you're out in the field and not connected to the mains in your backyard.