Michelle, I normally clean about 4 pieces at a time in my ss barrel. I have a 40 amp charger, but at times, especially when the pieces are large and aren't very dirty to start with, the needle will go WAY past 40. This makes the water so hot, that at times I have to shut the charger off for a couple of hours before I can put my hands in there, lol [smiley=kaioken.gif]. But as far as ruining the charger, I don't know, but mine still works fine :).