Q: ipad keeps resetting

Ipad 4 16gb retina plus wifi only

3 yrs old battery at 100%

all updates done as notified so on latest iOS

suddenly crashes to black screen then apple logo appears and disappears then resets itself and password screen comes on

enter password, full screen back then crashes again.

does this constantly at the moment

have no apps on now.

factory reset done, no photos stored etc,all content erased but it still crashes

what more can I do?