I have the 330 propress corded. I like it better then the cordless, but ran into a problem today. The job did not have any power outlets. I tried using a power converter to the battery of my van. All the specs say it should work, but when plugged in the green light on the propress flashes and won't work. Propress manual says if flashing it needs another power source. Anyone try this with a converter, if so what size, brands will work with it?