[Elecraft] Solar Panels on sale !!

[Daniel Reynolds]

--- "Dave G." <dmg at bossig.com> wrote:
> FWIW,
> Harbor Freight has a 5W 12V Solar Panel on sale for #39.99 !!
> 
> Usual disclaimers applpy !! Just got a Flyer in the mail  :-\

I just picked one of these panels (#41144) up on Saturday from a local Harbor
Freight. The panel is an amorphous design. I originally saw it listed on their
website for $35.

These figures are not precise, but I remember in bright sunlight the following
measurements I took Saturday afternoon (about local noon).

Open Circuit Voltage ~ 20 V
Short Circuit Current ~ 2 A

These values seemed high compared to another report I found online. One report
I've read online suggests it effectively produces 3-4 Watts. I'm going to run
my own tests sometime this week to find out how well mine works. Today it is
cloudy, so I can't run a more refined test with power resistors.

I currently have it tied to a 7AH gel cell to charge during the day. It sits in
the back window of my car with the gel cell in the shade. I have no charge
controller, so I plan on checking the voltage each day to make sure I don't
overcharge it too much.

The panel is nearly identical in size (18x12) to the side profile of the silver
colored aluminum tool cases folks have been buying from Lowes, Home Depot, etc.
Harbor Freight has the same tool cases (not just silver, but also in black
panel with silver frame). Because of the size of the panel, it won't fit inside
the tool case. It might be mountable to the side (it seems to be covered on the
front with glass to protect the panel - the back of the panel might be more
susceptible to damage), but I think that would not be as useful as having a
panel free to float around the picnic table pavilion on Field Day (or in my
back window where my K2 case definately WON'T fit). Maybe someone will figure
out a way to temporarily mount the panel to the case for travel.

I was able to generate enough power from the panel on Sunday afternoon (around
4-5 o'clock, with some haze in the sky) to power the K2 on receive (around 250
mA). When a cloud came over, the radio would die. When the sun returned, it
came back on. The voltage floated around quite a bit, but didn't seem to get
too high (not more than 15 V that I could read on the K2... probably because
the K2 was gobbling up 250 mA out of the manufacturer's stated 350 mA). When
the 7 AH battery was added to the circuit (KBT2 disengaged), the voltage
stabilized considerably (around 12.2-12.3 - I think the 7AH battery was low).

Only caveat I've read so far about amorphous solar panels is that they wear out
faster than single crystal cells.

For the initial layout ($40 + tax), I'm not going to complain. It seems to
perfectly compliment my K2 and the 7AH gel cell I recently acquired for Field
Day.

72,
Daniel / AA0NI
Oklahoma City