So I ran the battery out on my ST16. Missed that it was low in pre-flight (need to make a visual check list). Got a low battery warning, but didn't look close and thought it was the initial drone warning. It was out a bit and I didn't immediately start back, when I did, the ST16 shut down. Drone stops for a bit then I see it ascending to RTH height, then slowly head toward me, turn around, back up to over the take off point and come down a little then it stops. And it stays there, just hovering pretty high up. Now I'm worried, started charging the controller directly to a USB port in the car, but it's slow and won't power up. Keeping checking while just watching the H sitting in space. Don't know why it isn't coming down. After maybe maybe 8 minutes, controller still won't power on and I notice the lights on the H flashing to indicate low battery. Now I'm afraid it's running out of battery at altitude and it's going to fall out of the sky. It finally did slowly land. Could it be that the takeoff/landing spot had a tree and bench kinda near behind it? Anyway, lesson learned, no damage done. Haven't looked at flight log yet.