Lasts hours and doesnt lose any power. The only thing ive found is that it doesnt feel like it has that much punch compared to what a regular iron has. So i find myself upping the voltage and running it fairly high to lack the ink into the skin. Its super quiet. The most convienient machine ive ever used. I can literally tattoo snywhere with this machine, no need for clip cords, foot pedals and power sources, which makes setting up and ckean up so quick and simple. Feels comfortable in the hand. Ive gotten so attached to the whole convenience and comfort of this machine , that i doubt I'll ever use a coil machine again!