I can't find this bit of info anywhere, but what's the life span of the mini 2's motors? I've got over 300 miles traveled on the original motors and I don't want them to fail while I'm a mile away. And the other day my battery dropped from 50 to 30 all of a sudden and it's never done that before. Could it be a battery firmware update that caused this glitch? Thanks for any and all help with this question about the lifespan of DJI mini 2 motors.