[Elecraft] ... and solar power

WILLIS COOKE wrcooke at yahoo.com
Sat Nov 30 18:33:26 EST 2013 

All this talk about solar panels makes Green such an ugly color and the smell of gasoline and the roar of an engine seem so much more practical.
 
Willis 'Cookie' Cooke 
K5EWJ & Trustee N5BPS, USS Cavalla, USS Stewart


________________________________
 From: Bill Blomgren (kk4qdz) <billblomgren at yahoo.com>
To: WILLIS COOKE <wrcooke at yahoo.com> 
Sent: Saturday, November 30, 2013 5:13 PM
Subject: Re: [Elecraft] ... and solar power
 


The 70 watt panels will produce 2-3 and up to 6 amps when "fully illuminated" -- That means having an aiming system of some sort so that they swivel... Not something I'd put on a roof around here... (especially since I'm not allowed to.)
 
a 3-4 amp charge rate would take a while on a 100 amp hour battery... but still passable. (won't cook the battery either..)
 
Two of the 70 watt panels sound like what would really do the job.  Didn't realize that they were only 40 watt panels. The guy here had some 35 volt panels that he sells to the highway department for roadside equipment.  (You can never tell what he has in stock, however...) He's always out of stock at the end of the hamfest season, unfortunately.  (I would have gotten one of this 70 amp panels, and a charge controller...possibly 2 of them.)  Again, my location is SUB Optimal for solar, but at least I could have light and a small fan and perhaps TV if the power goes off...
 
KK4QDZ - Now with Extra Class Priv's, and a tiny KX3 to enjoy them!

From: WILLIS COOKE <wrcooke at yahoo.com>
To: Bill Blomgren (kk4qdz) <billblomgren at yahoo.com> 
Sent: Saturday, November 30, 2013 5:59 PM
Subject: Re: [Elecraft] ... and solar power



The Harbor Freight offering is the one that I have been wondering if it is worthwhile.  It is on sale tomorrow for 139.95, but it is three 15 watt panels for a total of 45 watts.  Using the information you collected it would mean about two days of good sun to charge a car battery.  You might be able to get two straight days of good sun on a Sport Fisherman at sea, but unlikely to get that much at a Deer Lease in your camper unless you are camping in West Texas or Arizona or some similar place.  The efficiency on a boat would depend on cloud cover and how much charging you can get from the engine alternator.  I would guess that the person with four batteries has separate batteries for cranking and is using the 4 batteries  only for electronics and housekeeping and using other batteries for cranking.  The electronics he describes sounds to me like a Sport Fisherman or a large center console with two electrical systems.  Most of these can get some
 charging from the engines when the cranking batteries are fully charged or at least nearly so.
 
Willis 'Cookie' Cooke 
K5EWJ & Trustee N5BPS, USS Cavalla, USS Stewart

From: Bill Blomgren (kk4qdz) <billblomgren at yahoo.com>
To: WILLIS COOKE <wrcooke at yahoo.com> 
Sent: Saturday, November 30, 2013 4:08 PM
Subject: Re: [Elecraft] ... and solar power



 
I've seen numbers thrown around at hamfests by a local solar guy - figure 50% of the claimed output of any solar panel since at normal 'earth level'  you might see "full" output for only a few minutes at noon.  He was selling a 40 amp hour led acid in a roll around cooler with a 40 watt panel attached to the handles for a reasonable amount. (I don't remember the exact number) - with a charge controller.  His comment was it would probably take 6 hours for the panel to take the battery from 10 volts up to 'full'.  He had panels there that were up to 70 watts, which is ok....and there is a kit from harbor freight that is about $150 or something for a 100 watt 2 panel (or was it 150/3 panel) without batteries...Throw in the charge controller, and the batteries...and you have a FAIR backup.  (The panels they use degrade over time, however.. loosing "oomph" after 3-4 years...)
 
They pulse the batteries in most cases, so that means that pulses are faster and a tad bigger when the panels are throwing out the most energy..at least until the battery is topped off.
 
KK4QDZ - Now with Extra Class Priv's, and a tiny KX3 to enjoy them!

From: WILLIS COOKE <wrcooke at yahoo.com>
To: Bill Blomgren (kk4qdz) <billblomgren at yahoo.com> 
Sent: Saturday, November 30, 2013 3:49 PM
Subject: Re: [Elecraft] ... and solar power



I am watching for such comments.  I am interested in the noise of the charger as well as the amount of reduced capability under less than optimum charging conditions.  You are correct in general about charging capacity and load capacity, but the charging capacity chosen needs to take the self minimum discharge which adds the minimum load and the self discharge load  as well as the maximum load and duty cycle.  One would not want to use a 0.5 amp charger to charge a 100 amp battery, but would a 45 watt 3.5 amp charger be adequate?  Typical manufacturer's specs will usually not advertise this but inquiring minds want to know!
 
Willis 'Cookie' Cooke 
K5EWJ & Trustee N5BPS, USS Cavalla, USS Stewart

From: Bill Blomgren (kk4qdz) <billblomgren at yahoo.com>
To: WILLIS COOKE <wrcooke at yahoo.com> 
Sent: Saturday, November 30, 2013 2:22 PM
Subject: Re: [Elecraft] ... and solar power



I'm exploring it myself... The actual wattage of the solar panel determines how long it takes to recharge- but the battery size is what limits your operating time.   The biggie is getting a *quiet* charge controller.  Many of them are very noisy electrically.  (Pulsing of charge current can provide lots of noise..)

There are some quiet charge controllers.  Watch for comments about them... Then again, if you are charging during the day, and operating at night off battery, it won't bother you.
 
KK4QDZ - Now with Extra Class Priv's, and a tiny KX3 to enjoy them!

From: WILLIS COOKE <wrcooke at yahoo.com>
To: "bill at wjschmidt.com" <bill at wjschmidt.com>; "elecraft at mailman.qth.net" <elecraft at mailman.qth.net> 
Sent: Saturday, November 30, 2013 2:19 PM
Subject: Re: [Elecraft] ... and solar power


I for one would be interested in more details.  Which products do you use?  What is needed to prevent overcharge.  What does less than full sun do to the capacity.  What sort of storage do you use and what sort of load do you service?
 
Willis 'Cookie' Cooke 
K5EWJ & Trustee N5BPS, USS Cavalla, USS Stewart


________________________________
From: "Dr. William J. Schmidt, II" <bill at wjschmidt.com>
To: elecraft at mailman.qth.net 
Sent: Saturday, November 30, 2013 11:44 AM
Subject: Re: [Elecraft]
 ... and solar power


I use these solar panels for portable operation.  They are at Dayton every
year and sell their blemished military panels to Hams.

http://www.powerfilmsolar.com/products/?foldable_solar_panels&show=category&
productCategoryID=6579&productCategoryIDs=6578,6579



Dr. William J. Schmidt - K9HZ / J68HZ/ 8P6HK/ ZF2HZ

Owner - Operator
Big Signal Ranch
Staunton, Illinois

email:  bill at wjschmidt.com


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