Today I got delivered a Cyma cm.125 handgun and with it came a cable to the station which you charge the battery with which is Ni-MH 6*2/3N 500mAh 7.2V. I'm not sure how long to charge it, when I plug it in the power brick led turns a red colour but does it stay become another colour/give any feedback when its done charging? If not how long should i charge it?