Are you CERTAIN that the battery was over drained? My PZ lipo carger does this every now and then. When it does I just plug the battery into the charger before plugging the charger in. I find that if I dont plug the battery in really "quick" it will do this. I'm thinking because all the pins dont connect at exactly the same time and freaks out the charger. As far as needing a "more powerfull" charger to charge a really dead lipo goes. That's not entirly true. You just need a charger that is capable of charging at a very low current level untill the battery reaches the minimum spec voltage. I recently got a Triton 2 so I could charge ALL my battery types. It has the low current charge capability for bringning lipos from the grave.