A full charge takes 20 seconds. Trident is also my recommendation to use instead. Trebuchet is an energy weapon.

Trebuchet's range makes you more survivable, but also less effective due to line of sight requirement, and not all maps are long-range friendly. Now I feel guilty, but my answer to your question is the same as what others have already pointed out - Zeus has very high damage, but 600m is too close for comfort in a slow robot. This sniper weapon can be charged up to deal more damage. Superheavy long-range energy weapon that fires bolts of high-temperature plasma, accelerated to enormous speeds. The Trebuchet is a long-range (up to 1,100 meters) heavy energy weapon. Able to charge prior to firing thus increasing total damage by up to 20 times. However, it can be fired at any time during the charge for reduced damage.

War Robots Trebuchet