Batteries primarily maintain ECM/ECCM and occasionally charge Phaser/ESG capacitors. They will provide their power for about half a turn. So 6 batteries can provide 6 ECCM for about 15 seconds, for example. (I managed to charge a Disruptor with battery power, but it was a chore.)
A ship can recharge its batteries at a rate of about 3.3% per second. However, only the first n excess energy can go towards recharging n batteries. Anything beyond that is ineffective -- you can't "fast-load" 6 batteries with 12 excess power in 15 seconds. Going from zero to full capacity takes exactly 1 turn, assuming excess energy is available.
If shield reinforcement is set high, batteries will never recharge...which is well-known to any Mauler-ship's captain.
Topic: How SFC's batteries work (Read 8700 times)