[Mobile-Portable] Solid State Amps - Battery & Floating Charge?

[K7fe at aol.com]

Doc, KD4E
Combining two amps in your car is only 1/2 an S unit and when you consider 
the additional battery and alternator requirements, not worth it.  Additionally 
the amplifiers may not "load share" evenly.
 
If you must because you want to be a "big gun" mobile station, consider this:
 
1.  Sell both amps and purchase an 8 transistor version that will provide 800 
to 1200 watts output.
 
2.  Your typical auto alternator will provide power for 75 to 100 amp draw 
(plus your vehicle requirements), so you will need a high capacity (200-300A) 
alternator which will cost $200 to $400.
 
3.  You will need a second battery about the same capacity (or larger) than 
your current car battery.  Where do you put that battery?  If it is in the 
passenger area or the trunk, it must be a "sealed" battery so that it does not 
produce toxic fumes or explosive hydrogen gas.
 
4.  Will your current mobile antenna handle the high power?  Many antennas 
will melt down.  A few like HI-Q will take the power and they are pricey (but 
worth it) if you need to purchase one.
 
5.  Bipolar transistor linear amplifiers used for a fixed station is never a 
good idea.  They do not amplify as clean as tube amps will and their cost per 
watt is higher plus you still must have a 12 V supply that is capable of 150 
amps...........price that one in your spare time.  Auto batteries in the house 
is a big no no.
 
6.  I was never fond of the capacitor idea, however it cannot hurt to have 
them at the amplifier DC leads input.  That is where I keep a second (sealed) 
battery with a very large charging/supply cable going to my alternator.
 
Your RV trailer is another issue.  I like a lot of batteries for electronics 
and lighting in my RV, so I have four plus a 6500 watt alternator and a solar 
panel.  You can do anything that you have the space and budget for, however 
you can have a great deal of fun with a barefoot transceiver and some antennas 
strung in the trees.
 
There is a photo of my RV on my QRZ.COM bio.  You can see the 40 foot motor 
driven crank up tower on the rear of my coach with a 6 element 10M KLM. 
 
Good luck with what ever you decide to do.
 
73,
Terry, K7FE 




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