Complete DIY solar tracker project
Design and practical realization with instructions of a low cost mobile solar tracker and performance comparison with a fixed solar panel system.
How to create two simple systems for the control of the rotation to be combined with the tracker for solar panels.
- INDEX
- - Philosophy and project guidelines
- - List of materials and tools required for production with estimated final costs
- - Dimensions, description of the parts that make up the structure of the solar tracker, construction tips
- - Features and descriptions with diagrams of the two possible systems for motion control.
- - Comparison of voltages and currents generated using fixed panel and solar tracker over a day
- - Situations where a solar panel with tracker can be more convenient and efficient
- - Support for implementation
- Philosophy and project guidelines -
The challenge of the project was to realize the mechanical and electronic part of a solar tracker for a photovoltaic panel (of variable size) among those on the market with powers between 100W and 350W, maintaining a low cost and small size for mobile use.
Once the specifications that the project had to meet were established, a research network was conducted to verify if other manufacturers had already achieved what we imagined.
From the researches and for some characteristics no practical realization had solutions present in our project,for the most part they were incomplete that is; excellent projects realized through CAD but only theoretical, sophisticated sun tracking systems using Arduino but with mechanical part only demonstrative or complete realizations very well studied but not within reach for costs and complexity to a DIY construction achievable by all.
Taking into account every aspects mentioned, the final result can certainly be improved and the product of several compromises however carefully evaluated led to the creation of a solar tracker for photovoltaic panels complete with mechanical part and system of rotation control with the following features:
- Iron structure with square section assembled with screws and bolts dimensions (without solar panel) of 1250mm - 80mm - 60mm L x H x W
- Sun tracking system on a single axis by linear drivers with inclined panel plane 30 degrees and rotation of + e - 40 degrees with respect to the solar zenth
- Original rotation position control system that does not use arduino or complex electronics and photoresistances for solar position detection
- Mechanical and electronic components required for easy to find and low cost construction
- Possibility of disassembly for easy transport by car
[ Deepening and motivations with advantages and disadvantages of the constructive choices used ]
NOTE: Although not used in the final design on these pages you will find electronic diagram for sun position detection circuit that makes use of photoresistors and operational amplifier for the control of a relay intended to power linear actuator.
- Materials, cost estimates and tools necessary for the realizations of the photovoltaic solar tracker -
For the main structure was used the 30 x 30 mm square section tube 1.5mm thick iron, 2 bars of 2 meters with about 400 mm of unused material.
For the joining between the parts it was chosen to use the 55 x 130mm galvanized pre-drilled plates, 6 plates are needed. The welding between the parts for the project has been discarded even if it would have saved costs as not everyone has a welding machine, for those who are in possession of it is still an excellent alternative solution to the junction plates.
For some "L" parts 25 x 3mm flat iron was used, 1 meter is sufficient.
All parts are assembled with galvanized M6 screws, nuts and washers, 2 screws are also needed, preferably M10 x 55mm stainless steel.
NOTE: to fix the solar panel to the structure of the solar tracker will also need aluminum profiles in these pages not mentioned as to be defined according to the size of the solar panel you want to mount.
For the electrical and handling part are needed; a 12 Volt linear actuator 150 mm stroke and an electonic timer type CN 101 or similar characteristics, the datasheet of these two components can be found on the "tool materials and costs" page,
3 relays double exchange 12 volts, a millephous breadboard for printed circuit, 1 light bulb 12 volts 21 watts.
For the realization of the electromechanical stroke sensor as it was preferred in the project is also necessary a sheet of plastic material of good strength thickness 3/4 mm size 300mm x 200mm that will have to be shaped as explained later in these pages.
NOTE: if you want to make a version with 24 volt solar panel all the components will obviously be chosen in the version with such voltage.
The minimum tools required are an iron hacksaw, a column drill, drill for M6 M8 holes and a soldering iron for the simple printed circuit for relays.
The cost of the listed materials excluding paint, is around 100/110 € or 110/120 $ in total.
[ Further details on materials and photo realization ]
- Dimensions and construction advice -
The dimensions of the structure assembled by us are 1250mm - 80mm - 60mm L x H x W so designed to be slightly lower than those of a 100w panel considered the minimum power to use. Therefore solar panels of larger size and power will stick out in length and width but this is not a stability problem being the very low structure, possibly for very large panels it will be advisable to increase the length of the support beam from the current 600 mm to 700mm or more. The connection profiles between the solar panel and the structure of the solar tracker are not mentioned in these guide pages as they depend on the size and thickness of the photovoltaic panels you intend to use, In our realization with panel 100w were used light aluminum profiles joined to the structure by "L" square steel plates with screws.
The description and order of the various phases is described in more detail on the page linked below.
Note: all dimensions are expressed in millimeters and threaded screws in ISO metric standard, at this link you will find the conversion tables inch sizes and UNC threads
[ Details realization and assembly sequence parts ]
- Solar tracking control systems -
To follow the rotation of the sun even if only one axis is needed a control electronics that rotates the photovoltaic panel so as to keep the solar rays parpendicular to the panel, this condition is the one that leads to a significant increase in energy production throughout the day.
In the experimental phase 2 rotation control systems were tested for solar tracking, the first, electronic with the use of a simple operational amplifier 2 photoresistances and a few other components, the second of craftsmanship mechanical realization that makes use of only 2 switches and 3 relays mounted on a printed circuit, in both systems is also necessary a 12v programmable timer at low cost that in the network is generally found looking for "CN 101A timer".
Between the two systems even if the one with with operational amplifier and photoresistances worked correctly during a short test was rejected in favor of the switch system, although it needs more work for construction has the advantages of greater reliability, no problem with excessive humidity or heat, no incorrect positioning due to particular weather conditions or branches of nearby trees that are moved by the wind deceive the brightness sensors. These characteristics,considering also the trasportability of this solar tracker,make it particularly flexible in positioning even in cases of objects such as poles, trees that go to interpose briefly between the sun's rays and the sensor, This unique feature is obtained taking advantage of the rotation steps obtained through the timer programming and stop switch.
- Programming of rotation movements with Timer -
One of the most original features of our solar tracker is that it uses a normal low-cost timer to control the rotation of the photovoltaic panel independently. On the "Electronic-controls" page or via the link below you will find an example of a program that we used a fixed solar panel versus a panel with a solar tracker to make the performance measurements.
- Comparative test of performance of fixed photovoltaic panel against photovoltaic panel on solar tracker -
After completing the realization of our solar tracker despite having already consulted yield tables made by others that are often the result of theoretical calculations or if realized on the field do not normally explain the conditions with which these results were obtained, we decided to make a comparative solar panel fixed against solar panel with rotation to see the differences directly.
NOTE: the purpose of the comparison is NOT to obtain scientific data applicable in other situations and plants but only to get an idea of the possible real efficiency gains obtained by our components under test conditions declared and replicable by anyone.
The test took place in the beginning of September in northern Italy, taking measurements using 2 meters connected one as a voltmeter and the other as an ammeter to the solar panel and recording the relative values.
For the test the structure of the solar tracker was directed so that the photovoltaic panel was perfectly perpendicular at the zenith point of the sun in the position to be considered as "fixed reference positioning".
Having started a day of full sun, measurements of volts and ampers were made every hour from 08.00 am to 20.00 pm, the first with fixed positioning and the second right after taking advantage from the rotation in the panel allowed by the steps of the tracker solar, in the table below the results obtained.
To have the test values replicable by others was chosen in passive resistive load consisting of 4 resistors of 10 Ohm 25 Watt in parallel for a resistance of 2.5 Ohm and dissipating power of 100 Watt, the solar panel used in the test is in fact declared 100W.
Finally, from the real data collected in our test we can deduce that more you move away from the zenith point of the sun more(as was obvious) the differences in performance become marked and the purpose of the test was to see how much, as well for the assessment whether a system with solar tracker was economicallys successful compared to 2 solar panels arranged at an angle, the conclusions in the following chapter.
[ For complete Volt and Ampere data generated and other test information, visit the Performance page ]
NOTE: The returns as you will notice from the table data are not linear, that is, as to the passing of the hours going towards the solar zenith the returns do not always grow because even if full sun day there may be light clouds or haze invisible to the eye but which do not escape to the photovoltaic solar panel, which you could easily check by connecting the panel with a load similar to our and tester on Volt measurement.
- Mobile solar tracker: situations where it can be useful and convenient -
After having realized our low cost mobile solar tracker and tested in the field the differences in performance compared to a fixed system we came to the conclusion that such system can be cost effective if you equip it with a solar panel photovoltaic starting from 200 Watt. This is because compared to the purchase of two panels arranged at an angle to have a similar performance throughout the day you will do without a panel and with the amount saved you can buy the components to build the solar tracker that will give you an excellent performance with less space requirements.
The situations in which it can be used are all those where there is no power line, so coupled with a simple charging unit and a battery will allow you in isolated homes, holiday homes or in situations of momentary lack of electricity to still have a source of energy to power light bulbs, laptops, radio stations, water pumps, power tool charging of 12 Volt, Smartphone charging, power supply portable tv etc..
- If you would like to make one using our project and should you find some difficulties during the construction phase you can contact us for clarifications and suggestions, we will reply as soon as possible -
