Introduction: Build Your Own Portable Solar Tracker for RV
A few years ago I submitted an Instructable for a portable solar tracker that was somewhat portable, but it was not easily transported or easily stowed in my RV. Many RVers like to "Boondock", a term used to describe camping without shore power, but there are not very many truly portable solar systems. Most of these systems are either expensive or not at all portable. A large solar panel propped up against a picnic table, with a heavy battery pack and a large Inverter is not what I would call portable or efficient and it is certainly not suitable for boondocking.
This build is ideal for use with an RV because it was designed specifically for flexible solar panels, which can easily be stowed beneath the mattress of an RV. The other advantage is that it can easily be assembled and disassembled. It is also expandable; you can adjust for any size panel between 50-watt and 100-watt using turn knobs.
You can build this system in a couple of hours if you have everything on hand. I have provided direct links in the parts list using Amazon Affiliate links but you can shop around and look for better pricing.
This project will involve modifying components by drilling, tapping and screwing parts together.
This build can easily be modified to suit your needs; you may find a better way to run wires or remove the tripod and solar mount for storing.
You might find that it is easier to mount the solar panel with adhesive backed Velcro strips, which would actually be a better choice.
Remember, this is a portable system and anything you can do to make it easier to assemble and disassemble will make it that much more suitable for an RV.
Someone with basic hand-tool skills can accomplish this project. This project does require tapping of the extrusion but that is easily done with the technique I describe.
Step 1: Tools Required:
The following is a list of tools that you will need to make this build. The best thing to use to tap the ends of the extrusion is an Impact Drill with an adjustable chuck. You don't need tapping fluid but it helps, any oil will do. To tap the ends use short bursts forward and short bursts backward. Don't be too aggressive. I have been using this technique for a long time and it works well. It works much better with tapping fluid.
Portable Impact Drill
8 mm drill bit
Miter Saw with a non-ferrous saw blade
Wire Stripper or Side Cutters
13/64” drill bit
Step 2: Assembling Tripod
The first step is to unpack the tripod and assemble it. Place the tripod somewhere out of the way but still make it accessible. Locate the steel square mounting plate that was included with your tripod and place it face-up on your work surface.
The link I provided is for a 12" x 12" sheet of PVC hair cell panel. It is a very good substrate for mounting components on. I recommend cutting it down to 10" x 10" to reduce the footprint. We only need it to mount a few components. Locate the center of the panel and drill a 1" hole.
Remove the pivoting bracket from the tripod pole, there are two bolts that fasten it to the pole.
Remove the bolt holding the plate and bracket together. There is a rubber grommet separating the two components, remove it. Flip the plate over. Now insert (4) 1/4” washers on the bolt you removed and insert it back into the opposite side with the countersunk hole. The washers build up the height so that they make contact with the pivoting bracket. The rubber grommet is no longer needed.
Now, reinstall the pivoting bracket and tighten.
Step 3: Constructing Top Portion Solar Mount
Locate the t-slot extrusion. If you purchased directly from the link I provided you should have (8) 25” (approximately) sections of 20mm x 20mm extrusion. Each section is cut to 22", there is nothing preventing you from making them 25", however, we are trying to minimize space. Also, flexible solar panels don't get much wider...only longer.
Please refer to the “Drawing & Dimensions” sheet for the cut dimensions. With a miter saw and a non-ferrous blade “carefully cut (3) sections to 22”. If you have never cut aluminum it can melt if cut with a dull blade or if cut too quickly. Allow the blade to do its job and don’t force it. It is possible to use wood blades but it will dull them and they can grab the aluminum very aggressively. Please wear safety goggles, a fragment of aluminum in your eye will ruin your day. These (3) sections make up the top portion of the solar mount.
Attach the 1/4-20 tap to the drill and tap the ends of the (2) sections. An impact drill with an adjustable chuck is the perfect tool for this job. You should always squirt a little tapping fluid first, but just about any oil will help. The secret is to go forward in short burst and quickly reverse the tap. Doing it by hand is slow and not necessary. I have been tapping with an impact on this very extrusion for the past 12 years and it is by far the best way to do it.
Tapping the holes allows us to thread in the 1/4-20 Button Head Screws you purchased. Thread them in but do not screw them all the way down, stop just short of the extrusion because we are going to be sliding the third piece onto them.
Lay all three pieces on a clean workbench as shown below. Center the perpendicular piece and space the other 2 pieces exactly 20mm apart, this is best done with a scrap piece of extrusion as a guide. Mark the piece with a pencil where the center of the screws would be and drill (2) 1/4” holes. These holes are how we access the screws.
Take the drilled piece of extrusion and slide it under the installed screws of the other 2 pieces as shown below.
Take the “T” handled wrench and insert it into both holes and tighten the screws.
The finished piece represents the top portion of the solar mount. It will eventually be mounted to the bottom portion and will slide in and out to allow for different sized panels.
Step 4: Constructing Bottom Portion Solar Mount
In this next step you will very nearly duplicate Step 5 except you will only use 2 pieces. The bottom portion has a single piece in the center. Tap one end of a cut section of extrusion and drill an access hole in the other piece as shown below.
The two sections, when joined, should look like this.
What you cannot see in the drawing are the turn-knobs and t-nuts that actually connect the two together.
Step 5: Installing Gear Motor to Enclosure
Mount the gear motor (pictured above) to the motor mount with the supplied screws.
Position the motor assembly on the PVC panel as shown below near the centerline. Place a mark in the slotted holes where the screws will go. Use M5 screws and nuts to attach the motor assembly to the panel. Slide the motor assembly toward the edge.
On the opposite end, we will install another “L” bracket to complete the “pivoting” portion of the mount. The picture below shows the walls of the enclosure removed for clarification.
Mount the 8mm coupler to the motor shaft. Align the coupler so that the set screw tightens on the flat area of the shaft to prevent slipping.
Take the 8mm shaft and insert it into the coupler. The threaded rod needs to be drilled through so that you can insert a cotter pin in it. Cotter pins can be purchased at any hardware store. The idea is to minimize the amount of play, the tighter the fit the better.
Once you have drilled and pinned the shaft position one of the "L" brackets (as shown) on the shaft. You will need to drill out the hole slightly. Thread an M8 nut and wedge washer first onto the threaded rod. Next, thread on a second M8 nut and wedge washer, this will secure the "L" bracket to the shaft.
The general idea is to support an M8 threaded rod parallel to the surface of the mount by supporting it on each end. The (2) "L" brackets are to be held securely in place with M8 nuts and wedge washers. A short section of 20mm x 20mm extrusion should be cut and tapped on the ends with a 1/4-20 tap. A 1/4-20 button screw is used on each end of the "L" bracket to secure it.
When the motor turns the threaded rod turns and the (2) "L" brackets move together. This is the pivoting motion we need to move the solar mount.
To attach the solar mount to the "L" brackets, pass a 1/4-20 x 10mm turn knob followed with a turn knob in each of the "L" brackets as shown in the drawing. The t-nuts allow you to slide the bottom portion of the solar mount on and off easily. Tightening the turn knobs holds it in place.
The best way to stow the solar tracker is by separating the tripod mount from the solar mount.
Step 6: Connecting Solar Frame to Tripod Mount
The tripod mounting plate should look like the drawing above.
What we are trying to accomplish is to create a “pivot” point for the solar mount. The shaft of the motor acts as one pivot point and the other end has an "L" bracket with a bronze bushing to provide a low-friction surface to ride on.
Align the turn knobs and t-nuts to align with the bottom portion of the solar mount (it is the section with only two pieces.
Move it so that about 11" is hanging down below the motor.
Next, slide the top portion of the solar mount onto the bottom portion (as shown in the drawing).
The top portion also has t-nuts that must be aligned with the t-slot.
This is how you will assemble and disassemble for stowing.
Step 7: Installing Charge Controller
To install the charge controller and the tracking sensor we need to separate the solar frame from the tripod mount.
Slide the solar assembly off of the tripod mount by loosening the t-nuts on the "L" brackets.
To mount the charge controller to the enclosure as shown in the picture above; mount it just below the motor and to the right. The Solar Tracking Module should be mounted to the left as shown. These are best mounted with self-tapping screws that are available at any hardware store.
Step 8: Installing MC-4 Connectors
The MC-4 connectors are bulkhead connectors that allow you to connect the solar panel quickly. There is one for each polarity. They are held in-place with a plastic nut. The metal connector does not have to be soldered but it should be. There are instructions online that detail the process. It requires a special tool (pictured above) to disconnect the solar panel. This can be kept on the side of your mount with a lanyard.
To install the MC-4 bulkhead connectors drill a suitable size hole to pass them through the Haircell panel. The best location is in the lower left-hand corner. You want them pointing down toward the ground and behind the panel.
The flexible solar panel comes prewired with (2) MC-4 connectors. They plug into the MC-4 bulkhead connectors. The connectors can only fit into their matching counterpart. The solar cables will snap into the bulkhead fittings without the tool, but you must use the tool to remove them.
Step 9: Installing SAE Panel Fitting
The SAE panel connector allows for quick connection of the SAE cable going to the RV. If your RV is prewired with the proprietary system "Zamp" then you will need the adapter shown in the drawing. The Zamp system is reverse polarity, the adapter just reverses the wiring for you.
The SAE panel connector should be installed opposite of the MC-4 connectors. It too should be pointing downward and behind the panel (shown in the drawing).
The short pigtail (red & black wires) will attach to the Charge Controller.
The SAE cable would then be plugged into the connector from behind and run to the RV. If you are using the Zamp prewired fitting then plug in the adapter and then plug it into the RV. If you are going directly to the RV battery then you will need to buy an SAE to alligator clip adapter, or other suitable connection.
Step 10: Installing Solar Tracker
The Solar Tracker has a remote sensor that exits the Solar Tracker Module via a single cable. Because we want to be able to disconnect the solar frame from the tripod quickly, we need to make the sensor easily detachable.
In the previous step you installed the Solar Tracker module to the tripod mount. The sensor comes prewired and attached to the module, the best way to handle this is to coil-up the slack and attach it to the mount with velcro straps.
The actual sensor needs to be attached to the solar mount, but it needs to be easily removed. It would be a lot easier to cut the cable and install a quick-connect fitting but it makes more sense not to introduce moisture or create a high resistance connection. So, we will just coil the unused section and use a turn knob or nut on the sensor. A quick release knob would make it a lot faster to remove the sensor for transport.
The sensor is mounted on a threaded rod. To attach it to the solar mount you can use any number of components to secure it. You could purchase a "T" bracket (shown in the drawing) that is held in-place with t-nuts and m5 screws. A turn knob could then be threaded onto the shaft, this will allow you to remove it quickly. You may find a better way to deal with this,
If your RV has the room to allow you to stow the tripod mount and solar mount as one piece then there is no need to disconnect the sensor.
Step 11: Wiring Diagram
The wiring is fairly straight forward once you understand the concept.
All "Red" wires represent positive and all "Black" wires are negative.
The SAE panel connector that mounts in the lower right corner of the tripod mount, via the red & black wires, goes to the Charge Controller "Battery" terminals; Red to Red and Black to Black.
The MC-4 bulkhead connectors, mounted in the lower left side of the tripod mount, go to the Charge Controller to the "Solar" terminals; Red to Red and Black to Black.
The Charge Controller comes with a "Load" terminal, it provides power based on when you want it to. The "Load" must be turned on to provide power.
Connect the Solar Controller Module to the "Load" terminals of the Charge Controller; Red to Red and Black to Black.
The two remaining wires on the Solar Control Module are "Yellow" & "Green", they go to the gear motor. There is no polarity but it does matter which lead goes to where. The motor receives power from the Solar Tracking Module when the Sensor detects light. The motor will turn clockwise or counterclockwise depending on how it is wired.
When the Sun comes up in the East the Sensor will detect the presence of light and when it does we want the solar mount to turn in an easterly direction. When it is aligned with the Sun we want it to stop. To test the direction of the motor requires you to shine a flashlight on the Sensor. This step will be done after everything is connected and mounted, in the meantime, we will temporarily connect the wires to the motor.
Step 12: Mounting Solar Panel
The flexible solar panels are attached to the solar mount via M5 x 10 mm turn knobs, a washer, and t-nut. Place a flat washer on an M5 x 10 mm turn knob and pass it through the solar panel grommet. Put on the top (2) and then slide it in the t-slot of the top bar. You may have to expand or contract the two sections to align the (2) grommet holes on the bottom. When the panel is in-place turn the knobs and tighten them. You may need more than one washer to get it to tighten.
Step 13: Initial Test
Please confirm that you have correctly connected all the components together. The solar panel MC-4 connectors can only be inserted one way and the same with the SAE connector that goes to the RV.
If your RV was premiered for solar it may have a Zamp connector on the side, if so you will need to also connect the SAE adapter to reverse polarity. Zamp connectors are the opposite polarity of a typical SAE connector. The adapter you purchased will correct for that. If you connected everything together correctly than you can test your system by pointing the solar panel toward the southern sky. The look angle will be determined by your latitude and time of year. There are online sources you can refer to get a better idea. For test purposes all we care about is facing south and that we have enough sunlight to trip the sensor. When the solar panel is connected to the MC-4 connectors and the cable to the RV is plugged into the SAE socket power is being applied to the Charge Controller. The Charge Controller, via the “Load” terminals, sends 12vdc power to the Solar Tracker Module. The Sensor, mounted at the top of the mount detects the amount of light and direction and sends a signal to the Tracker. The tracker converts that small signal to an amplified output to the gear motor. The direction the motor turns will be dependent on the Suns position. When the sensor is back in alignment with the Sun the signals will cancel out and the motor stops. This system does not have built-in limit switches.
Step 14: Disassembly & Storing
To disassemble your solar tracker start by unplugging the SAE cable from the RV. Then remove the MC-4 cable using the special tool. I recommend keeping the MC-4 tool attached to the mount using a lanyard, Velcro or magnets. Coil both cables and attach them to the solar mount. A Velcro loop would work nicely.
The sensor can be removed easily if you used a turn knob to mount it. Simply remove the knob, coil the cable with the sensor and attach it to the PVC panel. The solar mount can now be removed. Loosen the M6 nut (you will need a wrench) and remove it and the lock washer. Loosen the (2) M5 x 15 mm turn knobs holding the “L” bracket and slide it away from the motor. Now unscrew the 1/4-20 turn knob you installed on the bottom “L” bracket, be sure that it clears the hole on the other “L” bracket. Simply lift the entire mount and store it. If space in your RV is at a premium then you can separate the solar panel from the solar mount and stow the panel under your mattress or on an interior wall. You could also continue to break the system down by separating the two sections, or break them down even further. The PVC panel and tripod mount can be stowed as one and the tripod folds up very compactly. This is what makes this system so unique, you can break it down or build it back in a matter of minutes. This might be useful if you are transiting and won’t be setting up your solar for a few days.
Step 15: Parts Needed for This Build
The following items are all available through Amazon via my affiliate links. Please note that you can purchase these items from any source you like. You may find certain items for less.
The tripod and the mount are critical to this build because of the mounting plate. You can substitute the plastic enclosure with any watertight enclosure provided it stays within the dimensions of the tripod’s mounting plate.
Cost: $78.99 Quantity: 1
Cost: $8.49 Quantity: 1
Cost: $6.99 Quantity: 1
Cost: $23.88 Quantity: 1
Cost: $13.89 Quantity: 1
Cost: $5.79 Quantity: 1
Cost: $5.30 Quantity: 1
Cost: $5.22 Quantity: 3
Cost: $9.15 Quantity: 1
Cost: $38.99 Quantity: 1
Cost: $13.99 Quantity: 1
Cost: $45.99 Quantity: 1
Cost: $32.82 Quantity: 2
Cost: $11.98 Quantity: 1
Cost: $7.59 Quantity: 1
Cost: $7.49 Quantity: 1
Cost: $5.17 Quantity: 1
Cost: $4.76 Quantity: 1
Cost: $8.19 Quantity: 1
Cost: $12.59 Quantity: 1
Cost: $9.50 Quantity: 1
Cost: $11.19 Quantity: 1
Cost: $9.99 Quantity: 1
Subtotal (25 items): $429.67