Would give 0 if I could. Came in yesterday because...

Would give 0 if I could. Came in yesterday because my car died and I needed something to charge the battery with. Was told by 2 employees that the one I got (which was $70, but in the spot marked $30) didn't have to stay plugged in to charge the battery. I plugged it in for 27 hours then took it downstairs and tried to start my battery, only to find out it did have to be plugged it to work. And since I took it out if the box, they refuse to let me return it. So basically, I got lied to and scammed out of $70.