Portable Solar Trackers

Build A Better Mount

Every portable solar tracker I have designed was designed to be mounted on a tripod or on a wheeled base.  This might be alright for a 100-watt solar panel that weighs less than 5 pounds, provided we secure the tripod with a ground anchor.  A system like this will generate between 5-6 amps every hour, provided the Sun is shining brightly.  It also depends on if the panel tracks the Sun.

Unfortunately, we only have a few hours a day to produce enough power to replace what we used the day before.  This is made more difficult when we continue to consume power to satisfy our power needs for the current day.  In a perfect world, we would produce more power than what we consume or a surplus. If we are consuming 30-50 AH (ampere-hours) a day then we need to produce at least that much.  This is difficult enough with a large array mounted on the roof of an RV, it is not possible with a 100-watt solar panel, even if it tracks.

So, what can we do to produce more power without installing a solar array on the roof of an RV?

Fixed Angle Panels 


In my mind, installing a solar panel flat on a roof is equivalent to running an 8 cylinder car on only 6 cylinders.  We are only using about 75% of it’s designed potential.  If we were to lay a 100-watt solar panel on the ground and measure the output of the panel every hour from sunrise to sunset, you might be shocked at the results.

In addition to being inefficient, we have a limited amount of time to collect solar energy, about 3-5 peak-hours per day depending on location and time of year.  If we reduce the amount of light striking the surface of the panel caused by clouds or trees we will significantly reduce the output.  We have a lot of things working against us when we are trying to produce electricity with a solar panel, so doesn’t it make sense to increase the efficiency any way we can?

A flat angle solar panel is about 30% less efficient than a panel that tracks the Sun, so why wouldn’t we want to make them as efficient as possible?  The chart below illustrates the annual production of a fixed angle panel compared to a dual-axis tracking panel and it’s about 33%.

The bottom line, make your solar panels track when possible.

 

solar output

Building Up

The build plans I provide on the website call for a tripod mounting system, this is fine for a single 100-watt solar panel, but not at all suitable for larger panels.  If you want to produce more power quicker and more efficiently than consider modifying your system so that it can handle (2) larger panels.  This will require you to mount the tracker on a more stable platform.  It will also require some changes to the solar mount to handle the extra weight.  The challenge is to still make the system portable and lightweight.

For those of us that tow our RVs, we already have a receiver on our towing vehicle that provides a solid base for mounting a vertical mast.  There is an attachment that slips into the receiver that is used for flagpoles and antenna masts.  If we insert a section of pipe, the same diameter as the tripod pipe, we can now mount the solar tracker onto a very stable base.

Simoner, manufactures a 175-watt flexible solar panel capable of producing 9.1 amps.  The panel is approximately 60″ x 26″ and weighs about 7 pounds.  Installing two of these panels side-by-side would occupy approximately 4′ x 5′.  The weight of these panels and the mounting system would be about 30 pounds.  Each panel can produce 9.1 amps, realistically I would not expect to see that much but I would count on a combined output of 16 amps.  We could charge our storage battery much quicker (about 2-3 times faster) than with a single 100-watt panel.

We would need an additional gear motor or at least a more powerful one to handle the increased weight.  The mast would need to be high enough so that the bottom of the (2) panels would clear the rear of the towing vehicle.  It would not be practical to just install an 8′ mast in the standpipe because we still need to be able to stow it in the RV.  This might be made easier with (2) 5′ sections of antenna pipe.  Channel Master manufactures 5′ sections of the antenna pipe.

Pictured below are two examples of how this might look.  The Sketchup drawing I made shows how it would appear on the back of a truck.  It may require a stabilizer on days with mild winds, it would need to be removed entirely on very windy days.

The photo below is another example and an even better method for mounting.

 

truck mounted solar

mast-hitch-mount

A mount like this can still be assembled quickly and disassembled quickly.  The flexible panels, when laid side-by-side, are about 60″ x 48″ which would still fit under a mattress. The gear motor and the mounting panel would still be somewhat compact, however, the extruded frame would need to be designed to be folded flat. I am currently working on a folding frame to mount the solar panels.  More on this later.