Hi William, K3 #24 has been running on solar power since I bought it.
Our house electrical is set up a bit like yours, though we have a 48V system and FLA storage that covers the house if grid power disappears. The grid tied inverter is an older Xantrex SW4048. I added 2x 50W Siemens SR50 panels to the roof a little while after the main PV system was grid-tied back in 2002. That's a 12V system, nameplate-rated at 100W. The PV feed comes off the two panels to the radio room here on the second floor and is fused at 10A where is enters the radio room. That feed goes into a Micro M+ charge controller set to 13.56V to charge the SLA (lead-acid, sealed) battery. The battery is nameplate-rated at 110AH. All radio equipment runs off the SLA battery (K3, K2, scanner, even an inverter for 400W @ 120VAC). I'd say you can get away with < 50W of PV, and use the Micro M+ or eqiuvalent. The M+ is good for about 8 Amps if you upgrade the output FET. A 50 - 80AH AGM type battery will probably just about cut it if you're operating < 20W. Most of my ops are in that range, and I've found the 110AH battery is a wee bit of overkill most of the time (but very good for cloudy weather). You may also use the charge controller off a regular AC to DC power supply to charge the battery when solar isn't available or if needed for high duty cycle ops like contesting. I do this sometimes for those reasons. The Micro M+ charge controller is good for less than +14.5V out of the power supply because it behaves like an LDO regulator. Low voltage drops don't bother it. Good Luck and 73, matt zilmer W6NIA K3 #24 On Fri, 11 Sep 2009 08:01:47 -0400, you wrote: >Guys and Gals of the K3 ilk, >I am interested in setting up my K3 to run off of solar power but know >very little about what it will take. I assume a battery and a >controller/charger but what size battery would work best for operation >up to 10 watts, and what would work best up to 100 watts >(occasionally!) (and I do not need 120 pound flooded lead acid >batteries -- lighter weight, gelled cells in the 60 pound range are >preferable -- my back is not what it used to be!) > >Charging off the grid is acceptable at first, but the idea is to >switch over to the solar panel (what size, capacity?) as soon as I >can. I am familiar with solar power as I have had, in the past, solar >panels charging batteries for some of the house current (running >through inverters), although presently I only send the power back into >the grid without battery backup. Who out there is doing this for >emergency or regular use with the K3 and can offer some assistance? > >Bill, W4ISH > > >______________________________________________________________ >Elecraft mailing list >Home: http://mailman.qth.net/mailman/listinfo/elecraft >Help: http://mailman.qth.net/mmfaq.htm >Post: mailto:Elecraft@mailman.qth.net > >This list hosted by: http://www.qsl.net >Please help support this email list: http://www.qsl.net/donate.html ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
