Don, I think we are pretty much in agreement. I originally stated that a 33 watt charger was about right for a K2 and someone replied that it was way overkill. In practice, it takes a really good set of operators to transmit 25% of the time and few field day crews will do that. You experience with a 35 amp battery would tell me that things were just about in the right balance.
Willis "Cookie" Cooke, K5EWJ, PE --- [EMAIL PROTECTED] wrote: > Hi > > Actually 33 watts is more than enough to power a QRP > K2. You only transmit about 25 % of the time and > receive the rest so running a K2 at 10 watts will > only require about 15 watts to keep the battery > charged. For a 100 watt K2 you will need about 75 > watts of panels and about a 35 amp hour battery to > run continuously. I know this works because this is > the setup one of the operators used on field day > here in Tyler Texas a couple of years ago. The panel > was set up out in a field about 100 ft away from the > rig. The controller was one of my Solar Controller > Kits and the battery was a 35 amp hour gel cell like > used on electric wheel chairs. We operated night and > day CW at 75 watts out. The battery kept us running > all night and the solar panel had the battery back > fully recharged by mid day. > > > Don Brown > KD5NDB > > > > > Date: Wed, 19 Mar 2008 10:34:21 -0700> From: > [EMAIL PROTECTED]> Subject: Re: [Elecraft] OT - > Solar panel output> To: [EMAIL PROTECTED]; > [EMAIL PROTECTED]; [email protected]> CC: > > > > --- Ken Kopp <[EMAIL PROTECTED]> wrote:> > > We have > an RV with 12A of solar panels on the roof.> > They > charge a bank of 4 golf cart batteries with a> > > total> > capacity of 440 AH> > > > It's surprising > the amount of energy they will> > deliver,> > even > on a rainy day. Nothing near the 12A, but> > still> > > several amps.> > > > We have the experience to > back this up ... 5 years> > of six (winter) months > each on the Oregon coast.> > (:-))> > > > Didn't > want the idea that solar panels are useless> > in> > > the rain or a on a cloudy day to get started.> > > > > 73! Ken Kopp - K0PP> > [EMAIL PROTECTED]> 12 > AMPS of solar cells is a lot bigger than the 33> > watt unit that we were discussing. 12 amps X 14 > volts> is 168 watts. The 33 watt unit is less than > 2.5 amps,> barely enough to run a transceiver > continuously during> good sunlight.> > > Willis > 'Cookie' Cooke > K5EWJ> > _______________________________________________> > Elecraft mailing list> Post to: > [email protected]> You must be a subscriber > to post to the list.> Subscriber Info (Addr. Change, > sub, unsub etc.):> > http://mailman.qth.net/mailman/listinfo/elecraft > > > Help: http://mailman.qth.net/subscribers.htm> > Elecraft web page: http://www.elecraft.com Willis 'Cookie' Cooke K5EWJ _______________________________________________ Elecraft mailing list Post to: [email protected] You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com
