To produce 50 watts RF, its likely the Scout draws 10 or 12 amps at 13.8
volts. When your energy depends on power of back to haul the gel cells
or power of feet to crank a generator or power of the bank account to
buy solar cells your scheme isn't the first one that would come to mind
for efficiency. Because its not energy efficient. You have to supply 24
volts at 10 or 12 amps (240 to 288 watts) from the batteries to get 138
to 166 watts to the radio power connector to develop 50 watts RF. Your
DC efficiency is then about 57%. A little boost from a single 12 volt
gelcell to make its output 14 volts could be done with switching
technology at the boost of maybe 85% efficiency. That means to get 2
volts at 12 amps, 24 watts boost would require 28 watts from the
battery. So the battery would supply 12 volts at 12 amps, 144 watts,
plus 28 watts, total from the battery 172 watts to supply 166 watts to
the radio. DC energy efficiency 96%.
Unfortunately because of the need for current equalizing resistors for
the large bipolar pass transistors in most linear ham shack supplies the
efficiency is nearly as bad as your 24 volts of battery connected to a
13.8 volt radio with a linear regulator.
Perhaps fixing the root of the problem, excessive voltage drop in power
connector, wires, fuse holder, and power connector would be far more
effective and efficient.
Though one would have to settle for lower RF power output because when
the PA is matched for 13.8 volts its mismatched at 12 volts. There is no
simple cure for that.
73, Jerry, K0CQ
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