best ac/dc 4s capable balance charger

[_paralyzed_]

i've got a buddy in the army i'm building a brushless buggy for (the roller I just bought) and it will run on 4s.

I need to hook him up with a charger and prefer ac/dc as I believe this will be easier for him to haul around the world. (doesn't know where he's going yet)

I'd like any suggestions on the above, and wonder what the military guys think?? Is this the way to go or will he always have access to 12v? What do you guys do?