i thought it was the batteries too but its the same batteries i use for my 510 and 901 mods and they dont cut off. but when i put the 510-801 adapter, the 510 mod cuts off, same with the 901 mod with 901-801 adapter... so the batteries isnt the problem. plus i switch batts every 2 months. i tired every single penstyle atty(801,302,112) and it cuts off after a while