Basic Components of a Solar Energy Electrical System – Part 1

In this post I’d like to cover the basic components that make up a solar energy system.  In this system there are four basic components:

1.  Solar Panel

2.  Charge Controller

3.  Battery

4.  Inverter

The solar panel is what actually converts sunlight to electricity.  As soon as sunlight hits the panel it will start generating electricity.  There are roughly a million solar panels out there to choose from, ranging from small USB device chargers to the large panels that are installed on your roof.  I won’t go into much detail in today’s post other than to say you must figure out what your electrical needs are going to be and buy accordingly.  (Figuring your electrical needs is a post in and of itself.)

HQRP 20W Mono-crystalline Solar Panel 20 Watt 12 Volt in Anodized Aluminum Frame Square shape plus HQRP Coaster (See all Electrical)This solar panel is the one that I use at home for my small system.

Next is the charge controller.  This device is connected to the solar panel via cable and regulates how much electricity is passed to the battery.  Let’s say that you have a 12 volt system, typically you’ll need to have 15 volts or a little higher to charge the battery.  Most of these devices will stop the flow of electricity once the battery is full.

The battery is the device that stores the electricity for later use.  You can have more than one battery hooked up in order to provide more electricity (most battery banks are set up with more than one battery.)  These are deep cycle batteries and are designed to be charged and discharged again and again without damaging the battery.  Some resemble a car battery; however, car batteries are designed for cranking an engine over and don’t make good storage batteries for a solar battery bank.  A better choice would be a marine battery for a trolling motor or a golf cart battery.  These are designed for charging and discharging.

The inverter takes your 12 volt DC and turns it into 120 volt AC, so that you can use it with most household appliances.  Again, there are different types of inverters out there and you need to determine your needs before going out to buy something.

In the next post in this series I’ll show what I use for a solar energy setup that I want to use this summer for my popup camper.  Some people use small gas generators, but I thought a small solar generator used instead would be a lot quieter and more environmentally friendly.  And if the power goes out at home I can power a laptop and a couple of lights for many hours or my freezer for several hours.

 

 

Here’s a Sunforce 50048 60-Watt Solar Charging Kitcomplete system on Amazon if you’re interested in buying something without going through all the trouble of looking for components that will play nice together.solar set up

It got decent reviews and to be honest it’s got more to it now than my little set up does and it costs less!  It got pretty good reviews, but before you decide to jump on this don’t forget to do your own research first!

There are systems that you can tie into your home electric system, but you’ll want to get an electrician who knows the codes in your state to set it up.  This system doesn’t come with batteries, so you’d have to purchase those extra.

I’m not trying to sell stuff here – I just want you to be aware that semi-complete systems are available out there if you are looking to buy.

This is a big topic with a limited amount of space, so what I have presented here is a brief synopsis of all the various types of equipment out there.  In the next month or two I’ll be writing more about the components listed above.

-Jarhead Survivor

BTW:

If you have questions about solar energy please feel free to ask.  If you have advice, ideas, or experience with solar energy or would like to discuss different types of energy leave a comment below.

18 comments… add one
  • Prepared N.D. June 3, 2011, 9:02 am

    Here’s a handy little calculator that will show you how much your DC/AC devices will drain your storage: http://www.lifelinebatteries.com/marinesizing.php

    If your curious as to how much a panel will put out: if you can find the panel’s owners manual or performance whitesheet there should be a power curve in there that shows amps/solar radiation. You can find the typical solar radiation in your area by starting at your local NWS and looking at co-op weather stations in your area – many of them have instruments installed that measure solar radiation and this data is archived so you can look at how it varies from season to season.

    That will give you a rough idea of how many amp hours you can expect to put into your bank on an average day and how big of a panel you’ll need to capture the number of amp hours you need per day.

    The key word is efficiency. As an example, if you want to occasionally watch a movie for whatever reason – it doesn’t make sense to run a dvd player and TV off an inverter when you can use a portable dvd player or laptop that can run directly off DC and has its own battery. The laptop consumes more power, but can charge USB devices while you’re watching a movie – killing two birds with one stone. If you play around with these scenarios, you can get more mileage out of a much smaller system.

    Reply
  • Odd Questioner June 3, 2011, 10:07 am

    I can help a bit on the panel side of things (I work in the renewables industry).

    Photovoltaic (PV) solar cells nowadays come in two different general types: silicon, and “thin film”.

    The pros of the thin-film cells are that they’re cheap, physically tough, often flexible, and are fairly light and portable. However, the cons are exactly two: They tend to wear out (most have only a 5 year warranty), and you need more of them to get any real wattage out of them (typical conversion is at roughly 5-7% for consumer-grade models). Thin film cells rely fully on chemical compounds to work.

    The pros for traditional PV silicon cells are that they can last for decades (top-end panels carry 25-year warranties), put out more wattage (a top-end 4’x8′ commercial panel ships at 255 Wp rated power, and usually carry 17-18% conversion ratings). The cons are price, fragility (though still somewhat tough, they are more easily prone to breakage if you move them a lot), and relative lack of portability (you can find smaller ones, but usually they come in larger sizes). Silicon cells rely on the dielectric properties of treated silicon in order to work, which is why they last longer. Silicon cells come in two types: monocrystal, and polycrystal – mono will give you the highest power outputs, but they will cost the most.

    Overall, a lot of it depends on what you want to do with it.

    * If you’re outfitting your BOL/bunker/etc, go for silicon. It’ll cost a bit more, but they’ll last practically forever (panels made in the early 1970’s are still pumping out power at 60% of original), and you still get a higher energy density out of them. Just be prepared to shell out the cash for them.

    * If you want something you can drag around with you, thin film will be the way to go, but just know that 10 years on, you’ll be lucky to get 50% output, and 20 years on, they’ll be pretty much worthless.

    The overall price of solar cells are coming down drastically. prices of $1.75/Wp* (factory price) is the average on the high end, and $0.75/Wp (factory price) is common on the lower end products.

    Maintenance is as easy as keeping the things clean.

    One other tidbit to note: Even under a completely cloudy sky, you can still get around 50-60% of the rated output, but still, count that into your math! Buying/building a system that’s ‘just enough’ based on rated power will leave you short on cloudy days. If you’re relying on a solar/battery combo for TEOTWAWKI situations, then for the love of all that’s holy don’t count on full output. If you live in places like Arizona or such, you’re pretty much okay and can count on about 80% of output average throughout the day. If you live in, say, Oregon or Washington state (where it rains most of the year), count on buying 2x what you need. Also, check your latitude on the map. The further North you are, the worse winter will screw you over (and the better off you’ll be in summer).

    As always, plan accordingly. :)

    * Wp = “Watt(s) peak”. Solar products are not sold/priced by size or weight, but by the wattage they can put out under perfect conditions.

    Reply
    • Jarhead Survivor June 3, 2011, 12:26 pm

      Odd Questioner – I’d love to talk to you about a guest post. Interested? Contact me at jarheadsurvivor@gmail.com if so.

      Reply
      • Odd Questioner June 3, 2011, 5:18 pm

        check yer email :)

        Reply
    • Odd Questioner June 3, 2011, 6:25 pm

      Oh, PS: forgot to explain things about temperature. The higher the temperature, the lower the efficiency (which is why a panel in Phoenix will only get you about 80% efficiency). OTOH, if you get a panel with an aluminum frame (most large rigid panels are) and mount it a bit off the roof (to allow air to flow under it), you can mitigate that a little.

      Reply
  • Jennie June 3, 2011, 10:48 am

    :-) Jarhead mentioned figuring out your electrical needs, Greer had some interesting points about electrical needs versus mechanical needs vs lighting needs and the old practices of diversifying the household power generation, to include different sources for different needs.

    http://thearchdruidreport.blogspot.com/2011/06/in-world-after-abundance.html

    “There are a few things electricity does more efficently than any other form of energy – radio, broadcast or two-way; other electronic devices such as the phonograph; safe, smokeless lighting for the parlor and the kitchen for a few hours after sunset – and those were what people at that time did with electricity. (Nowadays a well-insulated refrigerator and the pump for a closed-loop active solar water heater might be worth adding to the same list.) Those things that electricity only does inefficiently and other energy sources do well – for example, providing diffuse heat or high-torque mechanical energy – people did by other means. Fairly often, those other means required a certain amount of muscle power, but that’s an inevitable reality of life in a world after abundance.
    The distinction between those things electricity does efficiently, and those things that it doesn’t, is as important to keep in mind as it’s commonly neglected.”

    The whole essay is well worth the time to read, at least once. :-)

    Reply
  • sgfxd June 3, 2011, 12:29 pm

    When you connect a series of batteries together- is it negative to negative and positive to positive?

    Reply
    • Odd Questioner June 3, 2011, 6:33 pm

      Depends on what you want.

      Connect two batteries negative-to-positive, and you connect them “in series”, which gives you the combined voltage output. (example, two 12-volt batteries hooked in series will give you 24 volts).

      Connect two (or more) batteries negative-to-negative (and positive-to-positive), and you connect them “in parallel”, which will give you the voltage of the strongest battery in the group. (example, two 12-volt batteries hooked in parallel will still get you 12 volts). Note that this is probably what you want if you’re hooking up to solar power.

      Pretty obvious at this point to mention that you should only connect like batteries together – both in voltage, and (if you can help it) in ampere-output (Ah) rating. Make sure your cables are a bit bigger, though – not necessary normally, but if you get a surge, you’re gonna get it harder this way.

      Final bit to keep in mind: if one battery craps out, it will quickly drain the others in the group. The rate of drain may be small (for a partially failing battery) to instant suckage (if one out of a pair dies quickly). Anyone who has ever had a pickup truck with dual batteries will know this one, in spite of such rigs having preventive devices installed.

      Reply
  • Jeff June 3, 2011, 1:37 pm

    Have you looked at wind power generation at all? In most areas, CC&Rs and HOAs would prevent it but if your rural, wind generators are supposedly much less expensive.

    Reply
    • gat31 June 3, 2011, 2:32 pm

      l was wondering about wind power for my garage. This house came with one of those very tall and sturdy old tv towers next to the garage, l’ve always wondered if a windmill on the tower would be enough to run the power in the garage and if so how? Do you get an in/con verter box? does it attach to the panel/power meter/outlet?
      Any help on this would be welcomed.

      Reply
  • GoneWithTheWind June 4, 2011, 11:25 am

    I installed 45 watts of solar panels on my motor home and a deep cycle battery (in addition to the two batteries the engine recharges). This gives me 2-3 hours of power for my laptop everyday. Even though I got the Harbor Frieght panels for only $199 I knew I would never get $199 worth of electricity from them. It was a simple decision to spend the money for a perceived benefit. However if you are talking about trying to replace cheap electricity from your utility then understand that solar panels will never do it. They are expensive and inefficient. They will never pay for themselves. I would recommend that everyone should have a minimum system that can run a LED light at night and a radio or computer for a few hours but as a replacement for utility power it simply isn’t practical.

    Reply
    • Odd Questioner June 5, 2011, 11:00 am

      Depends on what you want to get out of it, and more importantly, for how long.

      I apologize if the following offends, but it has to be said:

      The cheap Harbor Freight kit, for starters, isn’t the way to go. It’s like buying a Daihatsu compact car, then complaining that no one make a decent bug-out vehicle, so you shouldn’t bother beyond the confines of that car’s spec sheet.

      Let me explain: HF is a neat store to sniff around in, but not for big or serious gear. (we have the physical stores out here). Most of their inventory is fresh off the boat from Shanghai and Hong Kong, made by folks no one has heard of, and is often woefully under-powered/unprepared for professional day-to-day usage.

      IMHO, tiny portable solar chargers are *almost* worth their bulk and weight for what they do… but only almost.

      Now home/BOL power generation is where the practicality comes in. It certainly won’t be cheap, but here’s the trick… no form of power generation is going to be cheap. You’re going to have to expect to lay out the Benjamins up-front. You only see the money back way down the road. PV Solar panels usually pay themselves off after the 6-10 year mark, and start making you money after that (which is why you never buy a solar panel with less than a 15 year warranty). They pay off at the 6-year mark if your local power company has a feed-in tariff, at 10 years if they don’t.

      If you buy them direct from the factory (or close to it) things get cheap.

      OTOH, there are retailers.

      If I were serious about this, first off, I’d buy the panels almost direct, and to hell with the middleman markups.

      Let’s start with these puppies:
      http://www.wholesalesolar.com/products.folder/module-folder/SolarWorld/SolarWorld245.html

      245 Wp output, 25-year warranty (incl. a power warranty), and only $645/panel. 12 volts straight off the back. If I buy eight of them, I pay roughly $4800 + shipping.

      8 panels will give me almost 2 kilowatts at peak, or 2x enough to run an entire 3-bdrm apartment full of modern conveniences and toys. The other gear (mounting racks, inverters in parallel w/ spares, battery charging gear) will likely cost me about $500-$1k. The deep-cycle batteries will likely cost me another $1k. All together, the cost on-the-cheap for a BOL will run me about $7,000 for a 1.96kW station if I wire it up myself.

      Now a BOL isn’t going to have/need a big-screen TV with gaming console, a desktop computer that eats 450W, or such. You use LED or CFL lighting, which cuts the typical total wattage demand from 600-1000W total, down to around 130w total (for 10 CFLs, all turned on at once). You buy a fridge that’s only big enough to hold the absolute necessities (say, medicines) , which cuts the total wattage there down to maybe 35w for a small 4 cubic-ft fridge. chest freezer? maybe 25w (@ 300 kWh/year) more. Obviously you mix/match for what you want versus what you need.

      In a BOL situation, it’s pretty obvious that 2kW and the batteries to push it all 24/7 is a bit of overkill (though after 30-40 years, it would be perfectly-sized, though note that the batteries would’ve been long gone by then). OTOH, I used it to illustrate that yes, you can use solar panels to provide a huge chunk of your power needs (personally, If I’m going to set up for off-grid power, I’d sincerely want to have more than one means of getting that power).

      Reply
      • GoneWithTheWind June 6, 2011, 9:02 pm

        I’m not sure you understood my point. This isn’t about Harbor frieght or the more expensive suppliers. The point is simply this: You will never get back your money’s worth from PV. If you feel you need a small system to power a light for a few hours each night or to power a radio or laptop then by all means spend the money. If you believe you can power your home efficiently and effectively with PV you are wrong. It is grossly expensive and has serious limitations. Those who push PV usually are making money in the industry. PV pushers are worse then used car salesmen. I am disgusted by the exorbitant subsidies they have extorted from our politicians. Every time they sell their product they screw the taxpayer.

        Reply
        • BM June 7, 2011, 1:26 pm

          GoneWithTheWind,
          I understand the point you are trying to make, but you are as bad on the other side of the spectrum as those that say we should all go solar.
          The math is right in front of you.
          Say its 2kw panels for 8 hours a day for 60% efficiency. It will be higher efficiency early in life, less later in life.
          Thats 9.6kw/h per day. Thats 3500 kw/h per year.
          In Australia, electricity costs 20c per kw/h (or more). If you hadnt noticed, Australia dollar is now worth more than $US, but they are about parity.
          So this system would make $700 worth of electricity each year. So it pays for itself in 10 years. You then get 15 years of ‘free’ electricity, or more.
          So, remain disgusted if you like, but point out where this is wrong?
          Of course, solar works better in some places than others, but I can tell you Australia has a lot of sun.

          Reply
          • GoneWithTheWind June 9, 2011, 12:10 am

            I would be very suprised if you can average 9.6kw/h per day from a 2kw panel setup. Even is you live in an optimal location you won’t achieve that. But most people do not live in anything even close to an optimal solar location. For most solar (PV) systems they will never generate enough electricity to pay for themselves and that ignores the cost of money. However if you understand that money does indeed cost something and treat your expenses as a loan at 6% then you can discover that not only will the typical PV system never pay for itself but in fact you will go deeper and deeper into the hole every year. You are either a salesmen for these systems and accustomed to blowing smoke up your clients ass OR you simply are math challenged and actually believe the baloney you are dishing out.

            No PV installation, Commercial or private can ever generate enough electricty to pay for the cost of the system. Hence government subsidies and mandates. The taxpayers pay for the inefficiencies of PV (and wind) power.

  • Anonymous June 9, 2011, 12:52 pm

    GoneWithTheWind,
    You know what, this is why I rarely bother commenting on the internet. Both my brother and my mother have systems installed on their houses. Real world figures show they will pay for themselves after 12-15 years.(they had contractors install them, could have saved some costs)
    While a loan may cost you 6%, what are investment returns these days? If you have $10k to invest, would you put it into a 2% fixed return, or buy something tangible with it?
    But, you know, each to their own. I dont sell systems, I have no vested interest in it, other than seeing the world aim for a sustainable energy model.

    Reply
    • GoneWithTheWind June 10, 2011, 5:41 pm

      I can only assume that what you mean is that your family’s PV systems will pay for themselves AFTER you deduct the thousands of dollars the taxpayers paid to subsidize their purchase. You might ask yourself why, if PV is so practical and affordable, that it needs huge federal and state subsidies.

      It does not matter if you borrow the money or take it from your savings there is a cost of money. Generally it is based on the going interest rates and not on what a bank will pay it’s depositors. If your bank will loan you $10k-$20k for a PV system for less then 6% then good for you. But in general it is incorrect to calculate the payback period on your PV system without taking into account the cost of money. And it is immoral to calculate it how great your new PV system is without considering that the tax payers paid for it.

      There is now “sustainable energy model”! I wish there were. I have been experimenting with PV for over 55 years and I can tell you during that time the promises and breakthroughs were always just around the corner. But even after all that time PV is too inefficient and too expensive to be practical. If we don’t face reality and stop subsidizing failing alternatives we will never find/invent real alternative energy systems.

      There is a small bright spot in the alternative energy field. There are numerous things a skilled do-it-yourselfer can do to efficiently extract energy from the sun or the wind but they depend on low tech very cheap methods. But on a large commercial scale nothing has lived up to the expectations.

      Reply
  • ntuthuko majola February 16, 2016, 4:44 am

    I’ll appreciate to assisted on the following:-

    1. How must the solar cells/battery be connected to increase the output voltage?

    2. What range of solar in terms of output voltage and power?

    3. The detailed function of the charger controller?

    4. The detailed function of the inverter?

    Reply

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