Solar Controller Basics

The solar controller

Every energy collection system needs a brain.
  Otherwise things could get nasty real quick. A solar array of any size -even one panel- does to. Unless of course you decide you want to sit there with your multimeter in hand ready to disengage the circuit when your battery voltage gets to 12.8v/DC. Lucky for us solar controllers are pretty simple little devices and are therefore pretty inexpensive.

Basic Solar Controller

  A solar controller needs to do a few things as previously mentioned.

These functions include but are not limited to;

•   Keep your battery form overcharging      

  Most of the time the solar controller will be factory preset to a maximum voltage and you will have little choice in the matter. The industry standard appears to be borrowed from the automotive world at a safe 13.8 volts. This most likely isn't the optimum voltage to charge deep cycle batteries as efficiently as possible but it is a safe level. Some solar controllers have “field adjustments” that can allow you to up the anti a little to a higher setting. Voltage goes downhill so to speak, it will equalize itself across two points. Therefore you have to have a higher voltage to bring up a lower voltage. -i.e. to charge a 12 volt battery you need a more than 12v source- The highest voltage you ever want to charge an AGM battery at is 14.1 volts due to the bad things that happen if they gas, but more on that later.

• Handle unexpected spikes  

  Solar controllers are usually rated at the maximum amperage they will tolerate before failure. This number is actually a little lower than the true tolerance though due to government guidelines that require solar controllers to handle at least 25% more than their rated capacity. Early on there was an effect of cloud movement discovered that concerns us here and that is how cloud sides can temporarily focus higher levels of light on a solar panel and substantially spike production levels. But you shouldn't skimp in this area and purchase a controller that's 25% less than you will expect to need just because solar controllers aren't cheap.

•  Supply your needs for the present & future

   If you have to upgrade your solar controller every time you need to make an unforeseeable upgrade in your array you will be out of substantially more cash than if you just super size early. The difference in cost from one solar controller to another that is twice the size is far less than two solar controllers. You would be surprised at the number of people who commit to spartan electrical lifestyle in the beginning but wish for a little more "comfort" later.

• Stop back feed to the panel

  The last function of a basic controller is to stop your battery from discharging through the panel when there is no sunlight available and no power is being produced. (12.8v goes downhill to 0v remember :) The voltage loss is pretty small but newer panels are manufactured with the intention of the solar controller stopping the night time back feed.

 Relay solar controller

   The simplest of the lot are designed to just open the circuit with a mechanical relay (disconnect the wires) to keep the battery from going into meltdown. They are pretty simple, cheap to make, and are the oldest technology. The drawback here is that your panels go on producing energy without you collecting it. It leaves your panels on an open circuit and the voltage output spikes harmlessly. On another note any excess voltage above about 13.8 volts your panels produce gets lost to creating useless heat. Most panel modules will produce 17-18 volts in direct sunlight so the excess is just burned up through resistance.

PMW Solar Controller

  A newer version of solar controller employs solid state design -transistors- and goes under the generic acronym of PMW controllers. PMW stands for Pulse Width Modulated and with PMW controllers the opening and closing of the circuit happens so quickly you won't even notice it. By all outward appearances the voltage will stay at one level. With the speed at which this happens the controller will effectively keep the battery at a predetermined level. The advantage of this type of controller is the lack of moving parts to wear out and give you trouble in the future. There are also no contacts or points to get scorched. One drawback here is complexity for the sake of convenience.

MPPT or Muppet Solar Controller

   More advanced than the last we have the MPPT controller. MPPT stands for Maximum Power Point Tracking with this little puppy you gain 15% or more in efficiency due to its ability to convert excess voltage that the other controllers just loose to heat resistance into current your battery can use. This means that a solar panel or panels that produce 18 volts at 10 amps will give you 180 watts instead of the 120 watts you could expect from the older style solar controller. This feature can be a real asset in the colder months of the year when there just isn't sunlight for as long each day, but due to the colder temperatures your solar panels are working just a bit more efficiently. You need to up the amperage to help offset the loss of light you are experiencing and your batteries can absorb the extra power by taking more amps in a shorter time frame.

Non Pv Solar Light

  There is another way to harness the sun without all the wires and batteries. You can utilize the energy as it is created with the help of a skylight or solar tube. These kinds of interior lighting are incredibly efficient as you are taking advantage of the light its self with no losses in power conversion or storage. 

 The obvious drawback here is it only works for you when da sun is a-shinin. But that is no reason not to take advantage of its usefulness when it is. Houses, long ago, use to be designed with the sun in mind, southern exposures, big picture windows, (actually pretty poor at thermal insulating,) that are great for letting in light.

 
We tend to build on smaller lots now with fewer options, in some cases, to take advantage of natural lighting. We also build with relatively energy efficient materials to help us hold in the heat or air conditioning to help make our lives a little more comfortable. Unfortunately with smaller more energy efficient windows further handicapping our capacity to use this valuable resource. 

 

  The good news though is we can actually "pipe in" sunlight. With products like the tubular skylight we can enjoy the sun inside our temperature controlled environments. Not to mention save a little cash on the old power bill. 


   There are actually other benefits to letting in a little UV. Ultra Violet light has been use for all kinds of sanitation purposes. They are using it to kill germs and bacteria, mold and mildew, apparently it also offsets some of the ill effects of less than friendly old magnetic ballasted florescent lighting.   

 This type of technology should definitely be remembered in the struggle to become a little more frugal and a lot more energy efficient. If its already there you may as well use it to your advantage.  

 

Small Steps to Solar Independence

More info? Click here

 Not everyone can afford to go for the full off grid system right out of the gate but that shouldn't stop you from starting somewhere. I am a really happy to see smaller stand alone devices coming into vogue on the market recently. The technology isn't going to stop the world but at least its a start. I stumbled across this little gizmo here today and thought I would share. 

 It's a self contained solar light that has an extension cord to get the panel out into the sunlight to charge the 3 on board triple A batteries. I have seen several outdoor lights available listed as security, or spot lights but they mostly have the solar panel attached to the housing of the lamp itself. Where this one lets you get the panel out into the light with its 20 ft line so you can light up the dark little nooks and crannies during the day as well as at night. 

 The ease of installation permits even the less electrically informed among us to take advantage of free power without the hassle of playing with car batteries and solar controller and all that jazz. 

 The drawback to a system this small is a short life. It is only expected to produce light from all its 10 leds for 2 hours, and there is a low switch that lets you run it at half power for 4 hours (5 leds). If you want to just go out into the shed to grab a few things than 2 hours will be more than enough but if you  need to be out there for a little while than you may find it advantageous to get 2 sets that way you can produce up to 8 hours of light, in case your needs would so demand. 

 I think this will be a fantastic little setup if you need to get some candle power going in a dark spot without a candle or and electrician. This is probably the next best thing to a set I brought to your attention earlier in my article First Solar,Amorphous panels  . And its surely an easier way to get you on the road to your first solar experience.
 
 Though if you need a stronger light source than that, you should probably go for the amorphous panel set and get a 12v battery. Then you can pick up something like this florescent 12v light that will provide an amazing amount of light for its size and power consumption. These can be easily wired up to a standard lamp socket (like the ones in your house) then you just supply the 12v current and you are in business. Of course you can use the above mentioned amorphous panel set's 200 watt inverter to run any old household lamp as well.(albeit a bit less efficiently)

 Just be sure you don't get your 12v Dc (battery power, and solar panel power) and your 120v Ac (inverter power) confused.
  

Simple Solar Cell Explanation

 The solar cell. 

 Solar cells use differing materials with three basic properties, a positive material (P-type),like boron or aluminum (known as group 13 elements in the periodic table),  and a negative material like phosphorus, arsenic, or antimony (you guessed it... the N-type), with silicon (insulator) in the middle.

pure silicon

The process for adding these materials together is considered doping, in a semiconductor like silicone. The material is added as the crystal is grown to be included in the lattice of the crystalline structure. Normally silicon crystals have a repeating pattern to their lattice structure which leaves no room for electrons to pass and makes it a good insulator. By doping the lattice structure is interrupted to attach either an element that has excess (in the case of a n-type element) or is lacking electrons in the valence shell of its atomic structure (p-type). (dig deep... I know 6th grade science was a long time ago) In case you don't remember the valence shell is the outermost layer of an atom.(don't feel too bad, I had to look it up again myself)

N-type silicon (Si) doped with arsenic (As)

  So the couch potato,(excess and just sort of hanging out) electrons in the n-type can be knocked loose by incoming photons to be caught by the p-type silicon holes (openings in the valence shell). So in this way electrons can be collected by taking advantage of the voltage difference in the two materials created by the sunlight (photons) passing into the doped silicon lattice structure.


 To form an electrical circuit for energy to flow you have to have a voltage difference, electricity flows downhill, higher to lower. The solar cell takes advantage of this by having a P-type, and N-type node separated by silicon to create a positive and negative side that you can attach conductors to, to collect the electricity produced by the action of the photons knocking the electrons out of their loose valence bonds (N-node) into the holes in valence level of the p-node side. 

 This is just very simple explanation of the basic operation of a solar cell, there are many other kinds of materials used for the construction process I have not listed here. Not to mention several ways to combine the principles I have listed here to produce different kinds of solar panels. With differing construction methods and materials, different bandwidths of light can be accessed to produce electricity in different lighting conditions. Or increase efficiency by combining different bandwidth producing elements into one panel to increase overall efficiency.  To date I have heard of panels containing up to three different "cells" in one panel to collect photons the prior "layer" was unreceptive to. But you wont likely be finding them at a yard sale any time soon!!
 

First Solar, Amorphous Panel

  Any off grid power generating system has 3 basic components but may have several depending on the accessory options you would choose to employ. The first is the generating portion of the system; solar panels, windmill, generator, or hydroelectric generator. There are still others but these are apparently the most common.

 In this case I am going to be focusing on a solar generating system or PV. At the very least you are going to have a panel, a control module, and a battery to collect any power you don't use as it is produced, or for use in off peak production hours (at night). I have already answered the question "what is amorphous"  so I don't want to get into that here. But I do believe it is a good start to your first solar experience. Mostly due to cost. 

  Even if you manage to find an excellent extended warranty you may still be a little intimidated with the knowledge you are learning on a panel that costs more than the price you would have had to pay for a whole setup containing an amorphous panel. Also, the bit about it being a little more forgiving in the areas of shadowing and breakage, as I mentioned in the other article. In fact, I have seen people demonstrate thin film amorphous panels with holes actually punched through them every few inches with a hole punch to illustrate their durability and ability to produce even in these extremes.


 You will have to decide what particular kind of panel you want to start off with though. But even if you do decide to start off with a higher production panel I think it would still be wise to have some amorphous stuff around to pick up some rays when the higher output panels don't have enough light to start producing. So you could still have a place in your solar array for these panels even after you are comfortable with your newly acquired solar expertise.

 After you have decided what kind of panels to get you are going to run the power they produce through some kind of controller to access it. If you try to run anything more complicated than a dc fan off of the raw power from the panel than you are inviting disaster. Even something as simple as the fan may smoke at the open circuit voltage of panels which can be around 23ish volts in some cases. And even at that it is all variable depending how much light energy is actually being processed by your panel. 

  After the controller you will be in need of a battery to store the juice you produce. It is best to use the energy as it is collected due to inevitable losses in its storage, but that is impractical at times. I try to do most of my "heavy lifting" during peak production times, with "fresh off the vine" energy to curb my storage losses.  Like grind my coffee beans with the 100watt grinder or run my high speed rotary Dremle tool that uses similar wattage. 


  There are several choices to make in the battery department too. There is a mind bending amount of information on batteries that range form the metal lined jars recently discovered in the Egyptian pyramids to the sexiest noble metals only seen in R&D labs currently under development.  


 The most common variety currently available inexpensively though is of the lead acid sort. Even if we narrow that field down there is an incredible assortment of voltage and construction variants. 

 I am going to suggest here to use a common deeep cycle, marine grade, 12 volt, vented(the kind you can take the caps off of and add distilled water to),  lead acid, battery. Try to avoid the duel purpose variety for now, but if you can't find anything else it will do. Your battery should be over 100 ah, more is better here. This is an industry standard measurement that is meant to imply that a 20amp load will fully discharge the battery in 5 hours. You see ah = amp hours. So with a little simple math you can determine how long your battery will last (when fully charged), with the load you intend to put on it.  There is some cause for caution here though due to marketing implications that would incourage the purchase of a lesser battery. Don't be confused by other capacity designations like CCA =cold cranking amps or, CA =cranking amps, or HCA = hot cranking amps, or RC = reserve capacity.

 Unfortunately I can't, in good consonance, offer you a link. You see the lead acid batteries have an electrolyte in liquid form. This means it can spill and shipping is prohibitively expensive.  I encourage the use of this kind of battery though due to the fact that it gives you the opportunity to witness the effect of charging and discharging on the fluids in the cells (ACID). This is of value for 2 reasons I can think of right now.

 One is with an inexpensive controller that comes with most of the starter sets the voltage to the battery may fluctuate to a value too high to be acceptable, causing evaporation of hydrogen from the electrolyte. In a vented battery its no big deal, you just add more DISTILLED water. But in a sealed "maintenance free"  battery it will vent, If the input voltage creeps to high, damaging the battery and may-be you. 

 Two they are usually more expensive than their vented lead acid equivalent for the same AH rating. And so are the charging regulators (in some cases) required to offer you the kind of confidence necessary to feel secure in your first solar experience . So you are just going to have to find a local store to go buy a battery at.  Just remember the higher ah rating the better.

  

Mono-crystalline Panels

   
   Mono-crystalline solar cells are created by first growing actual crystals or boules of silicon then slicing them thin to put into solar panels. This is the oldest and most efficient type of solar cell commonly available. 

   Pictured here is a relatively low cost set to help you get started on your first solar experience, if you have a few more dollars to spend than would be necessary for a poly setup of the same wattage production. 

 Being more efficient, a mono-crystalline solar array will take up less space than either an amorphous or a polycrystalline solar system with the same output value. So this would be the perfect type of panel to buy if space is too much of an issue. This solar panel will suffer the same setbacks as a poly system but it will produce more peak power.  Being that this is a set though you will have fewer headaches in the initial install (which can make a first solar experience rough) 

 Even with the initial extra expense of this type of panel you should still see a savings in your utility bill by the first year easily. If you are really serious this kind of technology is the longest lived at a typical loss of efficiency of .5% or less a year. This particular guarantees 90% of total expected production to still be available in this panel for 10 years.  


  This is an excellent choice for a first solar set if you are in it for the long haul. 




 Pros

   Mono-crystalline panels have higher output levels per inch than the other technologies commonly available today.

  Mono-crystalline panels have longer expected lifespans than other tech

  Mono-crystalline panels are the old kid on the block so this is tried and true tech




 Cons

  Pretty much the same as the poly panels they are of rigid construction only and suffer loss due to shadowing.

   

   The set pictured here in particular comes with a solar controller with protections for your battery and other appliances. 

  It also has an inverter so you can plug your AC stuff right in.

Subsidized Solar

  I guess you may have noticed I have been posting lately on the solar panels available today. I am only part of the way through but I saw this link and thought the middle of the topic would be a good place for it. What it is, is a site that tells you what kick-backs you can get for going solar in your local area. 

  That's right kick-backs. (finally we get a shot at a few hea?)  There are state and federal dollars already set aside for you to make your home more energy efficient.  Imagine that, you pay less on your power bill and get a discount on setting up the system.  Some of the money is available as tax credit and I think there is some grant stuff on there too. I don't have time to search out what kind of stuff is available in every state but you can. Here is the link.  Da Link 

 Good luck. I hope you find something cool. It may not make an install free but I think you can get financing on this kind of thing and probably beat the power bill costs in relation to your payments.

Polycrystalline Solar Panels

Polycrystalline Solar Panels

 The poly panels are the next step up from amorphous panels in terms of efficiency, you can get a bit more watt for size, so you don't have to give up as much real estate to catchin rays.

   
  They are however a little pricier than their less efficient kin, but due to the manufacturing process utilized in their construction. They are still a good, lower cost alternative to fill your, first solar, need for power. 

  Polycrystalline cells are typically cast from a molten silicone solution to create a many crystal type of structure, hence the term Polycrystalline. The panel shown here is 12.7% efficient as apposed to the amorphous type that has an efficiency rating somewhere around 6-8 %. 

  Pound for pound though you will get a lot more bang for your buck with this kind of panel overall. Manufacturing costs are so much lower than the more efficient Mono-crystalline panels, and there have been advances in the efficiency of the poly type to make them a real competitor. If you have a little more to spend this would make a good first solar panel.

  Pros
   Polycrystalline panels are more efficient than thin film solar panels               (amorphous)
 
  Polycrystalline panels take up less room than thin film panels to collect the same wattage


  Polycrystalline panels are less costly to manufacture than mono panels so the consumer pays less overall per watt


 Cons
   Polycrystalline panels are heavier than amorphous and delicate to handle due to their cast construction
  
   Polycrystalline panels suffer greater losses from shadowing on part of the collection surface


  

   This kind of panel is the most popular in use as of now, due to the low watt to dollar ratio. This is certainly the way to go for a first solar system if you have a place to mount them that is rigid and out of the shade. Perfect for the roof of a house or in a field without any overshadowing structure.
  

 

What Is Amorphious, First Solar panel

  What is amorphous, in Latin it is spelled "amorphus". If you asked a Greek speaker "What is amorphous?" They would tell you it is spelled amorphous which is where we get the spelling in English.

 It's definition is; "having no determinate shape or structure, shapeless, unorganized."

 If you asked a chemist "What is amorphous?" They would tell you "Its of a solid: not crystalline, or not apparently so."

 Amorphous solar panels are usually marketed as "thin film Pv panels". They are constructed from a vaporized silicon and applied in an amorphous form or (a-Si). Amorphous  silicon being without apparent structure or shape is without the crystalline structure of conventional silicon Pv cells. Due to the non-crystalline composition it is flexible in nature, so when it is applied to a flexible surface it can form a panel with the same overall properties (flexible). A-Si can be applied at a low overall temperature so plastic can withstand the process and due to its flexible nature you can use it as a base for flexible applications. There are other materials used for thin film pv panels but this is the amorphous variety.



    
   If you want to try your hand at your first solar panel to produce electricity, it may be wise to start small. If you get the principles down with a small amorphous solar panel set (PV) than you will know better what to do with a full blown off-the-grid solar panel array to fuel all your electricity needs.

  The main thing to remember is not to run appliances that require more power than your first solar panel can handle.  As a rough rule of thumb...

What is Amorphous , Pros & Cons

The Pros

* Amorphous solar panels are produced by depositing a thin layer of silicon onto a base material in the form of a vapor. Base materials can be any number of things including glass, or flexible plastic.

* Amorphous cells also typically produce more power on cloudy days than some other technologies available today.

 * Amorphous cells are much lower in initial cost do to a less expensive manufacture process.

  * Amorphous panels suffer lower losses due to shadow casting across the surface of the panel and can produce closer to their rated output in these circumstances.

* Amorphous panels are less prone to failure due to damage because of the nature of the construction.

The Cons

* Amorphous panels have lower peak efficiencies than their higher priced cousins.

* Amorphous panels require more space per watt than other panels

* Amorphous panels can suffer permanent production losses due to exposure to extremely bright light

   I didn't want to get too technical here, I just gave you a general overview of some of the known properties of amorphous panels to help you figure things out. There is tons of information out there if you want to go check it out for yourself (which I strongly encourage). I personally have amorphous panels on my sailboat for our power needs for a few reasons.

First - the low initial cost is obvious.

Second- on a boat especially a sailboat I always have shadows bouncing about willy nillie and mono or poly panels would suffer more losses for it.

Third- I like the idea that I can crack a panel and it will keep producing power with whatever portion is still intact, (good to have on a boat, I have even heard of some people cutting off an end to fit in an odd spot, but I think this kind of abuse is frowned upon by the warranty people; )

  I am not too worried about the loss due to bright light exposure for the simple reason I never really have a good angle on the sun. If I do its not for very long before the wind gives me another little push.

  This may not be the panel setup for everyone but I do think its a good one to learn the basic principles of solar production, it's forgiving technology and it's inexpensive in case of the accidents that often befall a maiden voyage in unfamiliar waters. Last of all, it is nice to get everything as a "set" to avoid all the headache of figuring out all the capacities of all the individual components till you get a feel for things.

 Flip...

WOW long time no post

 It has been some time since I last posted, I actually thought I obliterated this blog but it seems to be a little more resilient than would be apparent. (guess someone is a little stingy about giving up content ;)  Since its still here I will give it another shot.       

         In my ongoing quest for FREEDOM I have gone nautical.  Having had an affinity for the water for a long time I am working on incorporating that into the search. I will still be reviewing the same sort of ideas I was before in my land based blogs but will likely be focusing more on things to facilitate life on a boat.  I am currently living on a sailboat

We are all environmentalist like it or not

   The environment is where you live. It doesn't matter if you are a hamster or a human. Most of the noise we hear on the news today though seems to revolve around some idealized sense of what environment is. The mind conjures up pictures of pristine natural woodland scenes with Bambi bouncing through the grass. Most of us however, who live in the city, may never even see such a picturesque example of gem quality babbling brooks where that dear drinks. Yet we are still included.

   When I think of environment or someone who calls them self an environmentalist I have a bunch of canned, media created notions, of people chaining themselves to trees and bulldozers,  carted off to jail by the bus load, getting a mugshot on the 6 o-cock news, and a labeled as an environmental terrorist.

    The thing is those people are not necessarily environmentalists they are activists.  The biggest advocates for the environment that I know of are much less marketable.

Plant a Tomato

   If we suddenly found ourselves without a viable income, could we adapt in time to survive? A premise like this would have, in recent history, seemed a little far fetched. Unfortunately though many Americans today are finding out it may be a bit more of a valid question than we would have thought even a few years ago. We all remember a time when employment was much easier to find. Giving us a since of security even if we weren't “in the market” and were happy with our current situations, at least we knew there were options if we wanted to choose them. Now things have changed. Not only are there few gainful positions available, many of us labor under the burden of the knowledge we may be “downsized” or loose our jobs all together for the sake of the bottom line.

  Even before the current economic woes we currently face in this country, studies suggested the average family could only make it for three weeks to a few months on their savings. What options do we have? It's pretty evident, the ones we create for ourselves, or the ones the government will provide. It is time to at least consider what we are willing to do to keep out of the soup kitchen lines for every meal, as lively as the conversation may be. What will you do?

Value

  Real options don't just fall out of the sky. We must actively seek them. Seeking the information to guide us in making decisions is necessary to make us capable of such decisions. The more open minded we are the more possibilities present themselves. We have been trained for so long that “beef is whats for dinner” we have closed our minds off to several other options. Sure we still eat pork, chicken, and fish (in spite of the cattle industry). But few are the acceptable options beyond that. Because of the limited nature of economically feasible production animals, and the success of big business in refining our choices down to the ones they offer...

Illusion of Choice

  We in this country are free to choose, as we are told, from youth. We can weigh available options to draw our own conclusion. We can come to any conclusion we wish. In the end, after all is said and done we feel like we have been completely autonomous in our decision. Sometimes, however the bets have been hedged...

Sustainability = Freedom

   This blog is not intended to speak to the growing number of people who already have an idea of what sustainability means. Not yet at least; it's more for the folks, like I know, that may have never had a thorough understanding of what the word means or why we should even be interested in it.

   So what is sustainability. I don't want to give some link under the word to a definition, because I want to explain what it means to me, personally. Sustainability to me is: over what period of time can this activity be supported. It is more than just a catchword for the people concerned about the environment, it is how long "anything" can be supported over time...

Freedom caretaking

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Community

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Freedom on a Raft

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Looking for Freedom

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