this might sound stupid but im pretty new to li-ion batts, so bare with me. Im using a 3.7v Trustfire 1200mAh 18350. I have read quite a bit on them, and felt pretty confident using them safely. I test the voltage often and i was wondering, when will I know that my batt needs recharging? I understand the PCB will cut off when the battery reaches too low voltage, but should I wait until then before I recharge? Or at which voltage should I think of recharging?