Question?? I got a new tool today.

Torsion bar? Gonna have to go slow. Can't tell if that's an 18 or a 20 volt, the 20v I have will definitely cut long enough on a battery to get through a torsion bar, and then some. But being spring steel if you go full speed with that blade you'll just take the teeth off the blade in short order. With the 20v DeWalt stuff I usually don't run at full speed with the Sawzall's or the drills if I'm cutting or drilling steel, full speed is so fast it'll smoke the blades/bits if you keep it up for very long. One battery will be enough, one blade might not be if you're not careful/patient. Just my .02. I haven't tried cutting a torsion bar with mine, but having used it on thicker steel that's what I would recommend.