The car is kind of dirty at both passenger side and driver's side floor mats and it is out of juice. OK, plug it in then start to vacuum. Bam! Power's out. And the circuit breaker at the central breaker box is at ON. WTH? Called several electricians around. Only one picked up. He said $240 a trip b/c it is a Sunday but he also said you'd better try to reset all the circuit breakers instead of the one you "think" controls the garage area. Miracle! Everything's back to normal. Lesson learned: the charger reads 120V, 12 amps which means another 9 amp from the vacuum is probably too much power draw for the circuit breaker.
it's probably not a bad idea to vacuum while charging if you plug the vacuum on a separate circuit. -- 12+9 is 21.
I flipped the breaker back and forth which I thought was the garage breaker but no avail. I also checked other breakers. Every one of them was firmly at the "ON" position. So it is possible that even the breaker is at ON position, actually the electricity could still be cut off? We used to have a breaker that refused to stay at ON so I have an electrician changed it but this time it is different. Each of them was firmly at ON position but no electricity in the garage. Weird.
Some brands of circuit breakers do not move the handle much when they trip. Some have a window that shows a red indicator when tripped, and the viewer needs to be lined up just right to see the red. A breaker can become defective and not reset. Or, that one is doing what it does properly, and it needs to be opened and closed perhaps with a good steady push in each direction. A quick flip may not allow the moving parts inside the breaker to get into their set positions.
