Doc,
I understand your line of thinking, but let me throw this out. I
thought about the same thing until I looked at the numbers. I bought a
Coleman Powermate 6250 for ~$400. Just before Hurricane Ivan hit us in
2k4. This generator puts out 5KW surges to 6250, and runs 11 hours on ~
5 gallons of gas. How much gas would it take to run a vehicle at 2000
rpm for that time? Most alternators in vehicles need a minimum 1500 rpm
to generate output. See attached image (This is for a 200A Powermaster
CS144 GM // alternator.) To get 200A out of it, you would have to keep
your vehicle running ~3500 RPM. You would need two of these in addition
to your normal alternator to be able to be able to supply the 416A+
required to put full load on that inverter.
73,
Craig (KB5UEJ)
kd4e wrote:
This has nothing to do with Amateur Radio, I am sorry
if I was unclear.
The primary purpose would be on the rare occasion where
a tropical storm or tornado knocks out power.
It would power the fridge or a small ac or lights until
power is restored.
Since we already maintain the engines in two vehicles
and they have large fuel storage it seems inefficient
to also maintain a generator for rare use.
They draw a LOT of current at 13.6 VDC. In this case, at 5000 watts
output @ 90% efficiency, the input draw will be 408 amps!!!
I'll second all of Dale's comments, and add this. What is your final
objective? If you could be happy with 500-600 watts RF output on the HF
bands, I strongly suggest that you look at a power amp like the Ten Tec
Hercules II that will be very happy supplying full output pulling 70-80A
from a 13.8V DC source. It takes only about 25W to drive to full power,
so the transceiver will add only another 10A. And that's keydown --
average current will be a lot less. You could probably buy that amp used
for about what it would cost to buy an inverter and clean it up enough
to actually use it in an HF station. Yes, legal limit power is another 4
+ dB up from there, but at what cost? If you can't hear 'em, you can't
work 'em! I don't know what other DC amps are on the market, but I'd
bet that there are others. I have a Herc II. It's a very nice amp.
73,
Jim K9YC
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