Just got my Riva today. My charger for my regular 510 batteries starts green, turns red when I screw the batteries in, and then goes back to green when they're fully charged. Vaped my Riva until the button started blinking, screwed it into the USB charger ( which is plugged into a Mains plug ), and the button light blinked like normal, but the USB light starts green and is still green with the battery screwed in. My kit didn't come with a manual. How will I know when my battery is charged? Is it supposed to stay green? Oh, and to clear up any confusion, I screwed my Riva into the USB charger that came with my kit, NOT my standard 510 charger : P