All Charged up I actually got this on accident, when you fire your Arc cannon at enemies it will automatically hit all nearby units, if you use it a bit you should get this on accident like I did but if it just doesn't seem to unlock, this is the guide for you!
(For those who want to boost)
BOOSTING METHOD: If you create a session with 12 people you can run into each other by having the host's of both lobby's change their server to Japan West! Then search in
Hardpoint Domination each other at the same time! Once you have a game, just meet up at a point (A,B, or C) and take turns killing 5 people in the titans!
Note: You get the Arc Cannon at lvl 21, make sure everyone has it attached in custom Titans before beginning the search!
Good luck and have fun!
Video: A well done job by The Box Bros for who that don't want to boost this