[Amps] 12V 120A Switcihng Power supply?

[norsan@bright.net (Norman Hockler)]

A simple solution to the 12 volt high current is to use a car battery.  The 
battery will supply 12 volts at 300 amps for relatively long periods of 
time.  A  12 volt 10 amp switcher placed across the battery and set for 
about 14 volts will charge the battery when the mike is not keyed.  When 
the mike is keyed the switcher will just fold back as the current it will 
try to supply will be more than it can provide.
I have used this method with no problems many times.

Norm  N8NH