120V Outlet Only Works when Truck is in Park?

As the title suggests, do the 120v outlets only work when the truck is in park? I plugged in the charger for my drills and noticed it stopped charging when I started driving. Whats the point of having an outlet if you can only use it when the truck is in park

 

The outlet is 400W while in park and only 100W while driving. 400W is mostly useless. 100W won't power much of anything.

 

That makes sense. The charger I was using was a 310W

 

There have been quite a few people who have modded these to be on full time but most of them also installed an additional battery.