I live in Montreal. I bought the unit last year after seeing my neighborhood use it on his car. I was impressed by the size but somewhat sceptical that it would work but he assured me that it does. I have had it in my car for the last year and never used it. This morning my sister in law's 8 year old Audi eTron (the original, built on the A3 platform) would not start. It's -7C and her battery was so dead she had to manually unlock the car. I had almost forgotten that I had the GBX45 sitting in my car. Once I figured out where the positive terminal was in her car (the battery is hidden somewhere) it took only a few seconds for the GBX45 to power up and be ready to boost and her small turbo engine started almost instantly even though the blue snowflake LED was on (solid) indicating that the unit was cold but still operational. I took the unit indoors to charge and it did so at 45 watts for perhaps 3 or 4 minutes and it was fully charged indicating that it was barely depleted. I think that this is an amazing bit of engineering and really, every car should have an appropriately sized unit in the trunk or glove compartment.