Bruce and Jean's Tiny
Travel Trailer -
The
Boxcar
Solar
Panels
Jan
03,
2010
I
recently
found
a great deal on a 135W solar panel from these
guys: Northern
Arizona Wind & Sun
It's a Kyocera, which is the same brand I had on the teardrop. They
have good quality panels that match their published performance specs.
It costs the same as the 85W I bought 4 years ago (Moore's law?). It
was the largest panel I could find that could be shipped by UPS instead
of by freight ($150 to my house was the cheapest freight I had been
quoted!!!). Its been sitting in the garage for awhile and I finally
installed it on our trailer over the weekend.
 Since
there's
quite
a
bit
of
performance to be gained by tilting the panel, I
came up with a tilting mount using 4 pieces of aluminum angle and two
pieces of flat stock. Clears the garage door with an inch to spare...
Here it's in the down position for travel. The panel is about an inch
above the roof, which is important when operating the panel in the down
position. Output drops with higher temperature so you need space for
cooling air to circulate around the panel.
 Here it is in the tilted
position. I used 1/4" cotterless hitch pins to hold it in the tilted
position as well as to hold it flat during travel. I put the hinge at
the front so it couldn't blow up during travel if I forget to put the
pins back in or they come out.
This
panel
has
reinforced
ends
so
I couldn't drill through the ends
like I did on the 85W panel. I bolted aluminum angle to the long sides
instead. Here's
the
hinge
where
it
tilts.
It's screwed into a spar so its pretty stout.
I really struggled with drilling a hole in my roof. Hope it doesn't
leak !!
 I
couldn't bring myself to make a hole in the roof while I was building
so I brought the solar wiring in through the side of the camper.
I still have to seal it up with pucky or something to keep the water
out. I only had some red split loom hanging around so I'll probably
change that to black sometime. I'll need to tape it to the roof or
something to keep it from flapping in the wind.
 Does
it work? The voltmeter says its charging, even on a cloudy day. The
panel is 59" long by 26" wide. Its probably overkill capacity but
since the new trailer has a diesel furnace that will run all night, I
wanted to make sure I had enough to keep up with the increased battery
demand. Now I need to figure out how to get on the roof to tilt it
without a ladder.
 Jan
24, 2010 Prices are so low for solar panels right now I added another
85 watt panel from UL solar on eBay. That puts my total at
220 watts.
The front panel doesn't tilt as it would shade the rear panel. I'll
loose a lot in output from the flat panel except during the summer
months so I'm curious to see what my combined output is. Besides,
I only have a 10 amp solar controller and the peak output of the two
panels is 12.3 amps. I kinda blew it there, I'll probably need to
replace it with a bigger one but I didn't think I would be adding
another panel.
 No
doubt about having to make sure the trailer is facing south. The pop
top will shade the panels if it's not.
Edit
Note: I replaced the charge controller with a Morningstar
MPPT. Here's why I picked this one:
NAWS
Review
 Feb
27, 2010 Okay, okay! This is the last solar panel I'm going to
buy. I've gone overboard on solar panels but here's a portable
solar panel I got off eBay. Its for the days I camp in the shade.
Its an 80 watt solar panel that folds in half and sits on the ground.
It has a leg in the back to tilt it up towards the sun. It also came
with a travel bag:
 The
connections
are
all
on
the
back. I've got 25' of good marine #12awg for
an extension cord so there should only be around a 2% voltage drop. It
came with about 8' of #18 wire with alligator clamps on it. I cut that
off and added a connector to the alligator clamps so I can connect the
panel directly to a battery if I need to.
 Here's
the
nameplate
data,
nothing
really
good or a really bad. Here's a view
of the wimpy cable that came with the panel. Since the leads from the
panels to the controller are short I left them as they are (for now)
rather than replacing them with bigger wire.
 The on-board
controller is nothing special but it works. It's NOT weatherproof,
though the panel will likely keep it from getting too wet in the
rain. I added a connection so I can power the trailer using the
on-board controller or I can connect it to the Morningstar MPPT
controller that runs the roof top panels.
 The panel only has
one leg to prop it up. It's not real shakey but I might add another one
so its a little more stable.
Here's the output in
watts using the onboard controller as shown on the Trimetric TM
2025-RV meter. It was a cloudy day so the panel wasn't putting out
a lot. I had tested it earlier and it was putting out 65 watts in good
sun. Here it's putting out 28 watts in cloudy weather using the
on-board controller. I switched to
the MPPT controller and the
output was 33 watts, about 15% better. I also
compared the output from the on-board controller with a Sunsaver 10 PWM
controller and found an identical output. The on-board controller
has an acceptable efficiency level so I'll keep it and that way I can
plug the panel directly into a 12V cigarette outlet using an adapter to
charge the truck or a friends battery.
 Here's the panel
folded in half. It has a handle as well as a latch to keep it closed.
It will ride in the compartment behind it in this picture.
So what's the bottom line? It's a nice panel if you don't want to put a
panel on your roof or you camp in the shade a lot. The power output is
what can be expected from an 80 watt panel and should be enough to keep
up with most people's Teardrop Trailer usage. The wires that came with
the panel are a little small for my likes but that's an easy enough
fix. The only down side is it's kind of heavy at around 25 pounds and
you'll have to watch it to make sure it doesn't grow legs and walk
away.
The on-board controller is a little suspect as its not weatherproof so
I'll be carefull that it doesn't get wet. The plus side is you can move
the panel around and track the sun for maximum power harvesting. The
panel is being listed on eBay for $299 which is a fair price when you
considerall it comes with. Misty gives it
two paws up!
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