Max Maker that's true and he need to prevent the mobile panel to refresh its position all the time.

Max Maker an keep any wires tucked away so no unnecessary shadows 🤔😎👌

Yes, in lots of his videos he gives up too early. That's a shame!

He didn't give up, he just needed to finish the video and publish it. That's just how it works unfortunately...

And different seasons. Because he lives in the northern hemisphere, this time of year the sun shines more straight. That's an advantage for the flat panel. If he try this experiment in autumn or winter, the percentage of increased performance for the moving panel would be much more.

make a pair of black abs pistons and resevoirs ... moutn a resevoir to each side (top and bottom to for all axis) ... and have the left resevoir move the right hand piston and the right move the left hand one ... same idea if you add a top and bottom ... top moves bottom bottom moves top ... then you dont need to use any power to move the panels and the sun will reset them as long at there is light .... over knight the panels will reset to mid point and be ready to adjust in the predawn light as the first light of sun starts warming it up .. so instead of waiting till 8 or 9 am to get sun you have it as day break and have it until it is dark out .... increased collection time automatic tracking with minimal maintenance and an added advantage you could add a piston overheat valve that would send excess heated water into your own hot water and limit how much power you have to waste heating up water to st in your hot water tank

@@0623kaboom do you have some link, which describes this setup in more detail? Thanks!

@@skythe83 I think he's describing a hydraulic system which uses heat from the sun to operate? Very interesting notion but I imagine it would take a lot of fiddling, and some sort of compensation for ambient temperature

didnt know that tip, thx

😂

Well, mistakes happen.

Ylläri Pylläri probably mm, don’t blame him, he is a boss.

boss at mistakes hahahaahaa

I wonder what's large then =>

just jokin... sorry if it hurts, i am fan of his engineering skills, he and martin Kobler are favorite Germans of mine

lol 🤣🤣🤣

Spoiler alert!!!

Me to

tbh a heliostat isnt really a tracker either ... it is a comparator and is used for comparing the light between the separated planes .. because of this it makes a great tracker because it can then be set to adjust to point at the most direct point to the source ... but it was NOT made to track the sun first ... it started as a heat seeker guidance system ...

tbh that version is crap it has to have power when all he had to do was install 4 lil home made cylinders on it and have the fluid in them heat and expand to push the panel in line with the heat and keep the panel facing the sun ... but nope he would rather take the miliamps and micro volts he has in short supply and waste most of them making something to follow the sun with power ... instead of following the shade BEHIND the panel

@@0623kaboom That doesn't work. The directional movement has to be controlled by the intensity vector of solar radiation not by the extent to which something heats up in the sun

It would follow the brightest area in the sky, probably the moon, or just stay in place if all sides are equally dark

It's all the programming matter. You can change the code, so that the tracker goes into sleep mode, when all photoresistors are in dark, and nothing weird will happen.

​@@stuartzhang6431 Lol this is genius. The simple solution is not always easy to come up with.

David Bay Pedersen Do you have it on Thingiverse? I'm thinking about making one with worm drives and L298N duel H bridge (run both motors). I probably won't make the same as yours, but I always like getting inspiration from other's ideas.

Infrared sensors and animal spotting?

Jake Garrett i Dont at the moment, but sure i just need to set up an account, i think it takes a Day or to before a Can upload files. Not gonna Lie the thing isn’t perfekt. One part do need a bit of love taking of the support, Never thought of contributing it so when i made it work never updated the file. This could be much different depending on the printer, my printer at the time had som problems with support Being tough. It was expected. All the trouble did make It more appealing to look at, so in my books its okay. Will post More details on thingiverse. As for motor controll i used brushed dc motors that are in a servobody. Do NOT recommend. It made everything tedious later. Use servos! If you are thinking about doing something like this, DO it. It is not that complicated. And you Will have great reactions :))

Lou Fazio no infrared sensors or animal spotting, not the point of the project

want a better one ... use the suns ability to heat fluids and have it do the work without wasting electricity ... basic hydraulics ... 4 black resevoirs (top, bottom, left and right) .... each resevoir when heated moves a piston on the opposite side to adjust the panel ... so left moves right top moves bottom etc ... any excess heated fluid (say water) can be used to heat the hot water tank and reduce power needs to do that as well ... a basic hydraulic system like that costs less ... needs less maintenance ... and functions better than any powered system ever would . another added bonus you will learn about hydraulics, specific heat capacity ... trajectory and astronomy and mechanical engineering and design ... and solar power ...and the best part efficiency .... just building it and basic monitoring and your project will almost write itself

Until you get the solar right, is it allowed to paint the roof tiles white with an outdoor-rated paint? That way some of the heat is reflected away instead of being absorbed

Yes that’s possible.

Usually people asked to rate comment and subscribe but this guy doesn't. I subscribed anyway because he is very good at what he does

@@sentient1705 it's because people forget about it.

I thought about that too. You know where the sun is at any given point in time. One thought though this system you don't need to know your location and time precisely or even at all. Also in my case I have some trees that shade part of the day. Clouds might also vary the best angle to point the array at. This overall is such a simple way to get to a solution. Not sure how practical it is with full sized panels. But very cool approach.

I mean, I just finished transcribing the NOAA solar calculator in a fork of Dusk2Dawn by DMKishi. No table necessary, just an RTC, and it calculates solar elevation and azimuth on the spot.

@MrAvant123 Thank you for doing that! Radar, starting from nearly nothing at the beginning of WWII, radar quickly became both quite capable and quite essential. Radars fundamentally like those -- and likewise the ones that you worked with -- are still keeping us safe from adversaries, mistakes, and just plain banging into things on foggy days. More recent developments like Doppler, phased array, and synthetic aperture radar do great things as well, but from start to finish the whole endeavor depends on knowing the signal direction.

or you could say fuck that ... and use the heat from the sun to heat fluid in a pipe on each side of the panel and the expansion of the fluid moves the panel into line with the sun .. same for top and bottom and he save that power he wasted with his tracker ... and has a reliable power friendly green solution instead of his botched power saver waster circuit

I was thinking the same effing thing, but instead about only doing a two-and-a-half-hour test. It's like he literally made this and was like I do not want to do this anymore.

Nice experiment, but none of this is needed. We know where the sun is every minute of the day. Its not going to dart about like your flashlight, its TOTALLY predictable for centuries into the future,. Just wire up your panel to a motor that rotates once every 24hours and set it on a polar axis. Job done. No sensors, no programming, no servos, no Aduino, nothing much to go wrong. If your 25% gain in performance is worth paying for, then motorise, otherwise leave it stationary. Obviously, you won't rotate 360 degree constantly, that would just twist your connection cables. It needs to be like a car windscreen wiper where the motor spins constantly in one direction, but the mechanism swings the blade to and fro across an agreed arc. East to West in the day, and West to East overnight. Simple.

@Shadan Rikan There are several reasons why, including that it will be pointing west in the morning and may take several hours to move to thee east. Its also out in all weathers so is going to be unreliable and the sensors will need cleaning. Car headlights and street lights will have the thing hunting about all night wasting some of the electricity generated in the day. No, its a technical answer that can't work in a practical situation, sorry.

0623kaboom Have you made or seen a working model of this design?

Suraj Grewal yes, far better in every way, including immunity to wind force on the panel, which is significant in a practical installation. Non-worm servos would be flailing.

Suraj Grewal Yes, that would be a great idea. I might have to do that, the L298N duel H bridges are cheap (drive both X,Y motors), and I have some heavily geared down RC motors that would work great for this. I just need to make a 3d printed worm drive, maybe use a screw or something for part of it. Now I've got my creative gears whirling, thanks!

or gone to solar heat and black abs resevoir connected to pistons and let the sun do the setting of his panels and not waste power moving the panels at all .. added benefit he can also use the resevoirs to assist in making hot water for his home ... yet another benefit .... he has no need to power any form of solar tracker ... just use a solar heater system

Yeah, Ave recently talked of something similar, a piston filled with wax.when it melts, the piston expands.

DC geared motor + window comparator + H bridge driver would be enough for tracking sun without MCU.

so maybe you have to connect a battery

I think you still need to drive the servers manually, because it won't be able to track as none of the 4 photoresistors got direct sunlight on it if the panel is facing the other way! maybe I'm wrong

Yes, but all you need is a battery back-up, a real time clock (you can actually do this in the code with a reference time input on startup) and some extra programming. You can then (at some point in the night, say 1 am where it's going to be dark at any time of year) set the panel position to a pre-set direction that is going to be at least towards the rising sun. Probably also a good idea to set a minimum light level and persistence before moving the panel so it isn't thrown off by nearby light sources like car headlights shining on it . Edit: Or you could seek every hour. So a timer runs every hour when there's no light which moves the panel through its full range and re-positions it to the highest light level position.

yup true ... if he went with a solar heater to move the panels instead pre dawn sunlight would readjust the panels in the predawn light and yup move his panels without needing to waste any power moving the panel array around ....

it would.

Raúl Almagro That was my first thought too. At that point one can even drive the mechanism with a basic timer.

The suns arc is moving up and down troughout the year. You would need to adjust for that manually every week or so. With a telescope equatorial mount you observe the stars just for one evening and it works great for that.

With an equatorial mount you can just manually adjust for the earth axis tilt depending on the time of year. Or even put it on a geared motor that automatically advances the angle once a day/week. The suns arc changes so slow though that it's accurate enough for months at a time even when doing manual adjustments.

Two or four adjustments per year are all that are necessary (10° off axis makes for barely measurable loss of energy generated)

But how much more effective will an equatorial vs alt, Azimut mount be in reality? I understand the mechanical benefits . I've got an HEQ5 pro mount my self.

Yes the tilt is depending on your local Position. There are Internettools to determines the perfect positioning to some degree

Q

a ball creating a shade would be for sky cover, the tube imitating a pyrheliometer is for direct-normal irradiation :)

MC's Creations he is the best

Gears

JAMES! Since the 70's You have to build for bad weather. A large panel is going to require some serious engineering to allow a small pivot axis and the strength to control that sail in a serous wind storm. You might look into what is used for the solar farms here in the California desert. The cheapest solution would probably be a rear axel from a small rear wheel drive car, as that could be rigged to give you a dual 90 degree rotational axis... but who wants a car axel on their roof, not to mention you will need to add a truss or two in your attic to support such a structure.. Personally it seems like too much of an engineering project for such a small return. However, if your looking to turn something larger, you can usually find the motor and gear box from an old power wheels type kids toy. You know, the little battery powered cars for toddlers. Those come with decent size gear boxes and a 775 type motor. The earliest models from the 90's come with the largest motors and gears. I pulled a couple out of the trash. People around where I live often throw these things out when their kids get older. You can also find the motors/gearboxes on ebay. Still, I wouldn't trust plastic geared anything in a storm on my roof. You know that panel is going to sail right into a neighbor's new car the first time there's a big storm... probably the most expensive car it can find too. -Jake

Jake Mitch yes. Gear it like a clock! Literally! Only go 6-8 hours and start over.

Upcycle Electronics I was thinking of pairing up the panels. On their own piviot. And connect with linkages. Like louvered shutters. Or the vents in a car . that a little lever that moves each louver. Or solar panels in my case. I am off grid. And need to get all the power I can while I can get it. The sun is behind a hill and trees until 10:30 or near 11 am. And going behind the trees again around 5 in the evening. I may just try a pair of panels and manually track the sun. To see if it's worth it. By manually I mean a slow motor and timer. And keep checking every hour or two that it is on target! A few degrees every 15 min. Should be close. Or maybe build a simple tracker with whe small solar panels and MOSFETs go turn in the motor. The majority of the panels are going to be basically the roof of a car shed. To keep most of the rain and sun off the card and what ever is under it. I have electric wheel chair motors and gear boxes. They can go really slow and still have loads of power. With a pwm controller. And they are 24v matching my battery bank voltage? Thanks for making me really think about it . you made some really good points!

If your only looking for a single pivot axis use two sealed containers on each side of the panel/mechanism with a fluid that evaporates connected across the middle. Build a mechanism based on a balanced pivot seesaw. The fluid should evaporate in the morning from one side and condense into the other container changing the balance weight and tilting the panel. Then you just need a low voltage comparator and relay circuit to open a valve and send all of the fluid back to the start when the panel(s) output drops to zero, or you could use a dedicated low power timer, or build a valve that uses the temperature differential of the night to reset a valve. Notice 'fluid' probably doesn't mean water. I doubt you'll get water to transfer fast enough, with enough volume. You'd probably need a solvent like alcohol to get it to transfer quickly through evaporation alone with high enough quantity. This setup won't work in the wind but if your 'surrounded by trees' you probably don't have a lot of wind to deal with regularly anyways. I always dreamed of building a truely off grid setup. I wanted to build a setup that separates the oxygen from hydrogen in a water electrolysis/Browns gas rig. You can't compress or store HHO as it is spontaneously explosive, but if you separate the oxygen you can compress and store hydrogen. Batteries are a short term storage mechanism. Solar panels are also limited by their service life. I wanted a concave mirror or lens focused on a boiler that powers a steam cylinder. Every mechanical part including a steam engine can be made using aluminum castings that can be made with a home foundry and machined using hobby level machine tools. This setup would then drive a small brushed motor/generator. You can actually cast your own replacement sleeve bearings and make your own carbon brush contacts to keep a brushed motor going for ages as well. An off grid solar panel might last you 10-15 years tops, and batteries will last you 2-4 years of daily cycling. Those need to be replaced. A HHO/steam/generator setup could last several decades with a good periodic service routine. Then you'd have a combustible fuel source and mechanical energy source. I always wanted to move somewhere remote and try something like that...before I became partially disabled... ya know the 'build a log cabin in the woods' kinda dream a lot of 20 somethings have. The ideal energy source would be a setup built on a property with a creek that can power a water wheel, but that's getting away from your solar panel aspersions. With solar panels my main concern would be keeping them clean and protected from UV damage. There's probably a 15%-30% deficiency just from a dirty panel. Plus, of the few used panels I've seen up close and delt with, they seem to have lots of UV damage from the various types of plastics used to coat or cover them. If the panel turns yellow or hazy after a few years that probably has a large impact on how well the panel works. Mitigating that problem is probably more cost effective than anything else. Personally, I dreamed of a mechanical system I could service as opposed to a substrate (panel) I couldn't reproduce myself. I watched a ton of videos from myfordboy on YT about hobby casting and miniature steam engines along with videos from many many others, I also have all of the David Gingery books about how to build your own machine tools from scratch, although I just got a little lathe/mill combo instead. I was super interested in that stuff back before getting hurt (bicycle ride to work vs car in 2014). If a person had a few fresnel lenses from a few old projection big screen TV's, a 20lb foundry casting setup that could run off waste engine oil (engine oil setup - means you could get hot enough for casting iron too), and a considerable amount of raw materials from things like cast car wheels/scraped aluminum heads, etc., a person could build a setup that gets them power off grid for decades and service it, at least in theory. Anyways...sorry for the TL;DR, ya just reminded me of long lost dreams and fun stuff I wanted to do, and I figured I'd drop some of my favorite source references in their too,... if you happen to have a similar interest ;) -Jake

Need 4... Needs to track up, down, and left, right. Sun goes side to side daily. But it also goes up or down during the year.

@@MrPhotographer77 might be underrated as a comment

I'm interest in this. Can you pls point to me a source to read more on that?

@@tawiahlot9926 There are many sun position algorithms out there with varying accuracy so there have to be papers about them. It's definitely not a simple topic but there is even an arduino library for it. I highly recommend that you read about how the sun moves in the sky, why the tilted axis of the earth affects this movement and why we have different seasons. It's a very interesting topic. A youtube video called "Patterns of the Sun" should be a nice starting point.

@@charimuvilla8693 thank you very much

then you would appreciate this ... . save them money on the tracker plants .. use HYDRAULICS and solar heating to move the panels and track the sun ... 4 piston per array 4 black resevoirs ... as a resevoir heats up it expands the fluid ... the fluid moves the piston attached to the oppisite side and adjusts the panel to put it back inline with the sun and balance it so all the pistons are at the exact same temp ... . if water is not used as the fluid ... but some form of antifreeze or glycol .. that fluid can also be used when it gains excessive heat with an automatic overheating pressure valve and an under pressure valve .. to dump excess heat to a heat exchanger (hot water tank) and top back up with normalised fluid ... no power, no fancy electronics ... limited maintenance and most efficient system to track the sun .....on an industrial scale it would cut costs about 30% just from the waste of using some of the solar power to track the sun ... and every system could use it and not truly effect the cost of the overall system ... more bang for the buck

This video is a catalyst for thought. The rest is up to us!

yshwgth knowledge is cumulative, no need to explore america again.

depends on if you want to play around or just get sht done :D

:D

A real man does whatever he wants, and does not focus on what people say "a real man" does. ;)

Why reinvent the wheel ?

Have an impression here: kzfaq.info/get/bejne/q7-Hq7Sdsre3fmg.html

simple ... make it hydraulic ... and you lose the power drop of the all the components ... and the need for electric circuit tracking and go to radiation heating and hydraulic expansion ...

What, are you crazy? You're comparing a flat solar cell to a tracked one. One hour will easily give a close approximation. And in the winter, the tracked one will 179 x out of 180 give a better return compared to the static, flat panel. That other 1 of 180 times it will simply equal it.

You should stay away from solar. Watch and learn something: kzfaq.info/get/bejne/Zsujhcmlv5nVlKs.html

LOL, 1) You're claim about needing 1 year to ascertain measurement results is ludicrous. Do you not know how science and math work? Do you think every engineer on the planet needs to spend a day, month, year on comparison measurements to come to a decision as to when one path is more efficient than another? Hint, no, they don't. In this instance, without having to wait for a year, it is possible through the magic of science and math to figure out loss/gain to a close approximation. www.solarpaneltilt.com/ 2) The 179/180 times example was for those with basic math competentcy. Flat plane is generally regarded as 180'. So seeing as a tracked panel will always outperform a non-tracked one, the only time a non-tracked one will even equal a tracked one is that 1' out of 180' when both non-tracked and tracked happen to coincidentally be at the same angle. The rest of your original comment is pretty obvious. You're statment that someone needs a full year to waste to measure efficiency/comparison is daft for the purposes of simply making a decision on which one is a better path.

I didn't say you needed a year to decide which was better. I said you needed a year to TELL HOW MUCH BETTER ONE WAS THAN THE OTHER. Learn2Read.

I understand math is hard. However, using it allows many of us to not have to wait a year to get accurate to nth decimal. Musk is shooting multiple rockets off a year, and he doesn't need to wait a year when someone gives him a slightly different destination, needed trajectory, final parking orbit. Fucking math, how does it work? knowyourmeme.com/memes/miracles-fucking-magnets-how-do-they-work

Like I said in the video, the movement of the servos is limited. That is why such a shadow could exist.

The shadow cast by the ldr would become insignificant once this system is scaled up in size to domestic supply panels.

Except you wouldn't scale it up to size, this system is not how actual sun tracking systems work - they just follow a planned path based on real time clock, this helps eliminate hunting. This is just a quick and dirty setup to demonstrate the advantage of sun tracking in principle.

@GreatScott: B.S. Your placement of the LDR blind is a bad design...has nothing to do with servo movement. You could have easily offset the blind for zero shadowing.

It doesn't matter - no shadow should be cast under any scenario.

TrolololGames A laser guided missile that rides straight into the sun, at least

Wowthatsfail The experiment would be just interesting, a real missile is way more complicated (r/woooosh ? I don't have a lot of humor with this)

You need an interference filter to block out all other light except that of the specific wavelength of the LASER for your Seeker head. In addition you could make it more complex with modulated coded signals and even with frequency (wavelength ) hopping

The early AIM-9 Sidewinder was simple as hell. To filter out the sun/clouds/water reflections you would use a spinning reticle - half is 50% translucent, the other half is a "chopper" with alternating opaque and transparent like a dartboard - which is a simple mechanical solution. The "chopper" would intermittently make the engine exhaust disappear which gives you the base "ambient light" that produces no movement. The 50% translucent half tells you when the target appears and disappears meaning in which direction you need to pitch or yaw. Because like in a pizza slice the chopper becomes wider with greater radius, the frequency at which the signal changes tells you the angle of the adjustment you need to make. To prevent the missile from locking into something else while it's "looking" directly at the exhaust (a bright spot at the center of the reticle would show a constant signal and confuse the exhaust signal with "ambient light"), you'd use a mirror to offset the incoming light by a few degrees so that the image is always "chopped" even when the missile is looking straight at the exhaust. Obviously the missile can't roll on it's axis (or else the pitch and yaw corrections will be incorrect if the missile rolls), so the tail fins have rollerons that counter the rolling movement.

Titanium Rain Thanks! that was very interesting!

That was my first thought as well. Since the actual track of the sun is no secrect, the search space is rather small and even an arduino should be able to handle it...

Just scrolling down looking for a comment like this, it took a lot more scrolling than I had expected

Unfortunately you're then subject to temporal noise and instability. This was definitely simpler to get working for an experiment. Another issue is that you need to explore 4 or at least 3 rotation directions whenever there's a decrease in the readings, and also periodically if there isn't, because for example the sun has moved but also the occlusion reduced and more light is available, so just because you found the position that gave you the highest reading a while ago, doesn't mean the position is still optimal. The direct comparison of 4 sensors (3 would suffice) is inherently stable, the worst that can happen is that you have a constant bias towards one of the sensors due to sensitivity differences. If you had to do this for real, you need to also take into account that moving the solar panel consumes energy, so ideally you want to move the rig with a pre-planned motion rather than hunting for light, and you also want to eliminate the inefficiency due to sensor bias and the panel thus being off-angle. So you could indeed have the solar panel as your sensor, but you would only calibrate it once with clear sky to find the true relative position of the sun, then you get a real time clock, get sun movement formulas depending on geographic coordinates, and calculate the rotation of the rig relative to the sun trajectory, and then just follow the trajectory automatically. You can also eschew the sensing altogether and get a shadow rig that will allow you to find the optimal orientation by shadow length of a perpendicular object on the panel, input the correction manually, and have the motion system take over based on formulas from there.

Siana Gearz, commercial sun followers do just this. They usually only rotate in one axis, as the sun follows a very predictable and straight path. As a bonus, some of them put the panel in horizontal state to get the maximum diffuse light when the day is cloudy and the production is low.

Fundamentally two-axis control is better than single-axis, because the sun changes angle during the year. However it is understandable that this adds a lot of complexity and cost, and might not be worth it for a small gain in energy output.

This was done just as an experiment...

what I was thinking too, I learned that from experience

Reminds me of the time I took apart some type of solar radio and tried to make a phone charger out of it. I glued both solar panels and an LM705 with hot glue. But it didn't work anyway so it didn't matter that it would've melted in the sun!

It does? In my experience it doesn't budge much below 100°C. I guess they are all different formulations. I'd be more concerned about his PLA prints, because those can start to lose shape at 60°C.

Silicon the best,..

dont use power to track the sun .. use hydraulics .. and the suns ability to heat a fluid ... more efficient all around ... 4 pistons 4 black resevoirs ... some hose and clamps .. and of course your pintle mount for your panel array ... . each resevoir mounts slightly beyond the edge of the panel array so it is mostly shaded (unless you plan on using pressure valves to also heat hot water and keep the system topped up) ... each resevoir feeds the piston to the opposite side .. top feeds bottom left feeds right ... simple cheap effective and no more maintenance than washing your panels and greasing you mount 2 or 3 times a year

0623kaboom funny you replied this - I came across rotating base homes also to track sun not only for the solar mounted roof system but for keeping the sun in the right rooms or desired rooms . There are many design options right knowing the art of the possible is something we are keen to understand

自由生活 they actually do that in real life application, but for the experiment this worked fine...

At each different location, at each different time, the sun's tilt angle is regular, assuming it does not take into account the possible deviation of the Earth's rotation axis.But it is the standard way of doing things. However, the use of light-sensitive resistors is indeed relatively simple.

+自由生活 There is professional systems that rely on mechanical system on both horizontal and vertical movement. From what I have read they are actually more accurate in the long run then any light-sensitive resistors where a simple thing that bird poo can make things really bad.

Yes, I just want to express this.~~

gerard dekort the math seems quite complex for a low power solar panel. You might use more power doing the math than just using the photo resistor method. Also, to account for the issue of the photoresistors being covered. The system could detect large differences between resistor values and could do several things to still be an effective panel. Such as using some preset angles based off time of day. For example, if its before 11 point east, if it's between 11 and 1 point up, if it's after 1 point west. While this would be less effective but would still likely be more effective than sitting flat.

ce neblock Yes :)

He can make piece of code that will avoid it

Kamil Maciej hmm...that would be hard. You have to determine if it is cloudy or just low light and regardless, you'd need to make sure that your movement doesn't cost more energy that it is worth.

This could be solved by adding code that says , if the 4 photoresistors are of the same value, do not move.

My Code: /*pr means photo resistor*/ if((pr1==pr2&&pr2==pr3&&pr3==pr4)==0) { //code that moves solar panel } Easy to add

Or you could program it (the 4th) to function as a fail protection... though I don't imagine they fail often, exposed to the elements, it is all possible for one of them to be covered with dirt, debris or bird poop.