Ridgeline17 is now 74 years old. I retired the old SawzAll and bought the Super. Looking to test out the better sawzall. I believe the vibration caused connections to battery to wear and cause intermittent stopping. I used 2 4AH batteries & 1 worked, 1 did not both charged OK? Then later batteries reversed problem! Sawzall had other problems so I concluded it is worn out and time to get the Super.