Edit: figured it out. Sticker over the back of the battery. Green light threw me off.
Is there some trick to making this work? I tried screwing down the head when I unpacked mine, but it didn't move very far. I tried plugging it in to charge, but it's just been sitting on a steady green light for over an hour. Tried putting the head back on, screwed it down, felt around the tailcap (nothing), screwed the head on and off a few times, fast and slow, nothing. Plugged it back in, nothing but a steady green light.
Is there some trick to making this work? I tried screwing down the head when I unpacked mine, but it didn't move very far. I tried plugging it in to charge, but it's just been sitting on a steady green light for over an hour. Tried putting the head back on, screwed it down, felt around the tailcap (nothing), screwed the head on and off a few times, fast and slow, nothing. Plugged it back in, nothing but a steady green light.