I'm surprised they haven't made a 12 volt truck/RV version of the keurig machine yet.
They'd be perfect in a truck if they were designed a bit differently.
First you'd need it to be 12 volts, and secondly the water reservoir would need to be designed more like a lawnmower gas tank with a diaphragm-type check valve in the cap that lets air in to replace the water when you use it, but won't let water splash out. The tank would need to be latched in place. Regular keurig machines water tanks are just set in place and held only by gravity.
Since 12 volt heating elements are slow, the timer would have to start 15 minutes early, so if you set it for 6AM it would start heating the water at 5:45 but not actually brew any coffee til you put a k-cup in and hit the button.
In manual mode, heating element on all the time, it would need an LED battery icon that comes on whenever the supply voltage is below 13 so idiots don't run down their batteries at night. But the manual mode would be so you can have coffee any time during the day when you're awake and the engine is running.