My old "Jump-Starter" died last year, so I bought a new one. It includes an air compressor. This one is so small I couldn't believe it could work. However, it seems that Lithium-Ion batteries have changed the game drastically. I only bought it after reading hundreds of very positive reviews on Amazon. I haven't tried to start a car yet, but it will pump up a tire without working hard. The charge indicator dropped infinitesimally (if at all) after pumping up a full size tire. The electronics and fail safe circuits on newer cars is so good that dead batteries are the thing of the past. I am going to try it on the engine on my test stand when I get back to Minnesota to see if it works. At this point, I'll bet it does.