It would seem 120/240 to 12v converters will be the logical solution for low-voltage lighting.
Regarding high-current dc distribution: I ran into that issue lots of years ago when I wanted to run some ham gear outside my travel trailer and use the 12v system as power source. I quickly found that 30-feet of #14 or #12 wire would not do. I finally used a 12v battery and floated it from the trailer power. And I was only running 150w on 2m. At one time I was considering solar power for a two-story log-cabin in the bush, but the wiring gets expensive (so do the panels). The cabin now has 120vac utility service so its a moot issue (and I sold it in 2003). My present shack has 13.8v provided by 50A Astron which is connected via a 12-foot run of #6 welding wire to the main 30A buss fuse. This connected to a heavy barrier terminal strip to provide power to all the amplifiers and high-current equipment. I see about 13.5v at the main fuse when running loads; unloaded it shows 13.75v. Two power leads run from there to two more barrier strips: one is #12 solid house wire and the other #8. Both about 3-foot long. My new 144-28 50w transverter runs off the strip fed by #8 wire and voltage runs at 13.2 under load. My K3/10 is fed from the #12 wired strip. There are only two other items connected there: panel lights for my manual antenna tuner and the main station controller (fused at 5A). Many of my new amps require 28vdc. I have a 8A and two 50A supplies for 28vdc. One 50A PS runs the 16-foot dish rotator-motors and will run 432-100w and 1296-300w PA's at the dish. I run #12 romex out there for 120vac power (remotely switched). The other 50A PS may go to the base of one tower where I may install some big amps for 900 and 1296 MHz. To place the amps at 50-feet will require #6 wiring up the tower. Installing a switching PS at tower-top becomes attractive (not the 90-lb. 50A PS). Ohms law rules dc-wiring! Ed ------------------------------ Message: 5 Date: Sun, 03 Apr 2011 11:05:02 -0700 From: Jim Brown <[email protected]> Subject: Re: [Elecraft] Local Noise Problem To: [email protected] Message-ID: <[email protected]> Content-Type: text/plain; charset=ISO-8859-1; format=flowed On 4/3/2011 10:12 AM, AB8XA wrote: > The sub-panel will also have a 30 amp circuit to my "shack," feeding a 24 VDC to 13.8 VDC converter for full nominal voltage to our 100 watt rig. There are many advantages to 24 VDC over 12 VDC in residential use. Yes, BUT -- that 24VDC to 12VDC converter is almost certainly some sort of switching power supply, and you will need to carefully search to find one that is not a source of RF noise.. AND the conductors are going to need to be pretty large, because they're carrying a 10A load (at 24V) just to run your 100W rig. Multiply that current (and copper) by about 9X if you also want to run a 500W amp. And the only one I know of that runs on 13.8V is the Ten Tec Hercules II, a very nice amp that's been out of production for about 20 years. 73, Jim K9YC 73, Ed - KL7UW, WD2XSH/45 ====================================== BP40IQ 500 KHz - 10-GHz www.kl7uw.com EME: 144-1.4kw, 432-100w, 1296-testing*, 3400-winter? DUBUS Magazine USA Rep [email protected] ====================================== ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[email protected] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
