Teardrop Trailer Solar Panel
| I
had a few very definite ideas about this trailer. First, I
wanted to have a solar panel on it. Second, I was going to use
only LED lighting, so there would be minimal electrical load for
lighting. Third, I wanted an electric refrigerator, but what
kind? The first cooler I tried was a Koolatron™, with a Peltier Diode array for the cooling This is a large solid state electronic diode which "produces cold" when electricity goes through it one way, and gets warm when electricity goes through it the other way. This unit does not have to be level, like a gas refrigerator, and it does not use a compressor or refrigerant like a "regular" refrigerator does. The only moving part is a small fan for circulating air around in the unit. The price was also very attractive. There were some drawbacks, though. It has limits on how cool it will get. It would only get about 40° below the ambient temperature, at best. This was not good in warm climates. I also had to use a block of ice, because the solar system could not keep up with the electrical demand from this cooler. |
I was not at all
happy with the performance of this cooler, and decided that it
was not suited to be a refrigerator for my camper. I got a
Waeco™ refrigerator, which has a compressor and refrigerant in
it, just like a regular household refrigerator. It runs on 12
volts, and just uses a very small amount of electricity. It also
has a 120 volt option. In addition, it is very,
very quiet. It also does not dump a lot of waste heat into the
galley. I also had to learn to set the thermostat so it would
not freeze everything inside it. This has been a wonderful unit
for us, and I recommend it whole-heartedly.
It is about four times as expensive as the Koolatron™, but worth
every penny. I did have to make a different switch setup for a galley light. The handgrip on the new refrigerator would hit the light switch when the galley lid was shut. The remedy was simple. I just made a recessed switch. |
| My solar panel is
rated at 80 watts, and is just the same width as the trailer.
The mounting brackets that came with it were a generic sort of
bracket which I decided would be inadequate for my desires. I used some 2" x 2" x 1/8" aluminum angle on both long edges of the solar panel. This makes for a sturdy mount and also keeps the wind blast from getting under the panel and causing some mischief.  the full-length aluminum angle molding can be seen on the edge of the solar panel - the panel is mounted between the galley lid hinge and the roof vent |
The charge
controller that came with the solar panel kit was a compact
circuit board which I mounted in a home-made aluminum box on the
ceiling of the trailer cabin.  Now, my wife and I each claimed a certain side of the trailer, and it turned out that the charge controller was on her side. It interfered with her ability to store and retrieve the bulky items stored above the drawers. Logically, it would interfere with me, as well, if it were on my side. What to do? I found a different, smaller controller. It was self-contained and very sturdy, compared to the delicate circuit board of the first controller. It is compact and vertically mounted , out of the way. I did eventually move it to the other side of the vertical pillar - to my side of the trailer after this picture was taken.  |
| In the real world,
an 80 watt solar panel will only produce that much power if the
sun hits it at right angles to its surface and the sun is fully
bright. This would require mounting the panel at an angle of
about 45 degrees in this part of North America. A hinged
adjustable panel mount is possible, but would be more
complicated and involve lots of moving parts that can shake
loose. In actual practice, I found that this panel works nicely for me as long as I have good sunshine about half the day. The other thing is that I am using the Waeco™ refrigerator. With the Koolatron™, the battery could never get fully charged. The Waeco™ refrigerator is our key to campground electrical independence. I can run this unit for a couple of days with very little sunshine, if I start with a fully charged battery. I hooked up an extra wiring harness to take power from the car's electrical system to charge up the battery on cloudy days. This works well, but it is important that this setup only be used while driving, and disconnected whenever the engine is not running. This is a little awkward, but it is simple and works for me. The garage that hooked up the connector on the car used a part of the car's circuit that can be energized by the trailer's battery. I could probably connect a blocking diode in the wiring to prevent this, but it is easier to just disconnect the trailer from the car when it is shut down. |
The GoPower
Engineering™ charge controller that came with the solar panel is
a decent unit, and has displays for voltage, current and state
of charge (battery voltage, actually). But it is just on a
circuit board and not too sturdy. The SunSaver™ controller is a very rugged unit, ready to mount. It lacks the displays of the first controller, having only a green light when the unit is charging. It does have a very good feature missing from the first controller. It can disconnect the load from the battery if the battery voltage drops too low. This protects the battery from being drained too low, which can damage the battery. This feature requires an extra circuit which I do not now have, so I can not take advantage of it. |