[Al Skierkiewicz]

Guys,
Battery chargers rarely put out a pure DC voltage. Never use them for power supplies. Often they put out a pulsed DC that averages about 13 volts but peaks much higher. Popular 50 amp chargers just connect a few diodes to a big transformer and add a few lights and an ammeter and call it a day. Remember that a wet or gelled cell battery will charge (current flows) if the input voltage exceeds the battery voltage. That is why 50 amp chargers are not allowed for our batteries as the high current is capable of destroying the battery. (read that catastrophically) The charger supplied in the kit is a smart charger and won't even turn on unless a valid battery is connected and in need of charging. The internal electronics test the device connected before supplying full output current.
As for the compressor, start current is about 25 amps while run current is about 10 amps. Again, start current on the Chalupas or the Fisher Price is over 95 amps. With many of the modern power supplies, the start current (of even one motor) will force the supply into current foldback or just simply trip the breaker. The supplies that go into current foldback will not go back to normal output until the load is removed or the power is reset.
And you don't want to turn on a power supply at a low voltage and run it up with the electronics. For starts the RC is disabled until the input voltage is above 8 volts.
Although the breaker is rated at 120 amps, if you look at the curve you will see that it can handle a 600% overload for a few seconds and can handle almost 200% for 40 seconds.