The most important thing for you to learn about chargers is the minimum amount of time it takes you to kill a target, and the range of that shot. For example, 3k liter takes about 60% charge to kill a target with 3x attack power and the range is about 15-20 feet (in the testing area). Another thing is learn to aim fast and once you've learn to do that, learn not to aim at your target until you've got your minimum charge otherwise they know you're aiming at them.
I'm sure there's other ways to play a charger but this is what I learned to become decent with them.