Why is this happening?

[Sabienne Maceus]

When my phone's battery drains so it's yellow my phone randomly powers off then turns on again. For some reason it's also faster then when I restart it myself.

 

[paintdrinkingpete]

When my phone's battery drains so it's yellow my phone randomly powers off then turns on again. For some reason it's also faster then when I restart it myself.

It sounds like it's doing a "hot restart", which isn't a full restart -- it's kinda just like shutting down all active applications, and it is faster than a normal reboot. Why it happens or whether it's normal I'm not sure, I generally don't like to let my battery get that low. FWIW, today's modern batteries are pretty great compared to previous generations when it comes to "memory effects", but you should try to not let them run all the way down to zero if you them to perform at their best.