SFB Tournament Tactics and Discussions
Batteries and Phasers are capacitive systems: the power you put into them on one turn can be used on a later turn. This is different than charging a heavy weapon and holding it in that once you charge a capacitive system, you do not need to expend any resources to keep it there. Once charged, always charged. The advantage of these systems are that they allow you to spend your turn-to-turn power on other things, while you slowly drain the capacitive system of power to feed what it's attached to.
An example is that you may start with a phaser capacitor of 8 points and spend 5 during a turn. The following turn, you might send only 2 more points of energy into the phaser capacitors instead of replacing all 5 energy (allowing you the same 5-phaser strike you recently used). When your opponent allows you some breathing room, you can then bring the phaser capacitor back up to it's full levels. This then allows you to later spend you energy elsewhere.