Basic wiring diagram of a simple solar power system

Solar Power System Diagram | 4 Basic Building Blocks

Solar power systems vary widely in their power producing capabilities and complexity. But I wanted to sketch a simple basic solar power system diagram that shows the building blocks.

Regardless of a given system’s capacities and specifications, there’s a common thread among most of them: The basic building blocks of its major components.

1. Solar panels
2. Charge controller
3. Battery bank (if off-grid or standalone system)
4. DC to AC inverter for AC power

Solar Power – System Diagram

I’m posting this for the beginner or the curious. The basic diagram.

The basic solar power system diagram. This does not include the additional related various subsets of components which may or may not be required depending on your installation. Things like interconnecting cables, solar panel mounts, brackets, branch ‘Y’ adapters, combiner boxes, circuit breakers, shunts and meters, grounding hardware, and other details).

First, Is Solar Power Worth it?

It depends on your objectives! First, lets face it… To implement solar energy is not cheap compared to today’s energy from the grid. Though the costs of solar are coming down!

One could argue that from strictly a cost savings point of view it might not be practical.

It may take years to reach a break-even point. Why? Because a cost analysis of a solar power system compared with that of your electric utility bill will speak for itself.

Depending on the system design and usage, the break even point varies widely.

Hover, It’s Worthwhile for Many!

Despite the cost of a given solar power system, for many it’s a worthwhile investment.

Example: If purchasing a new property with land far from the nearest road with electric utilities, it may actually (very likely) cost less to implement a solar power system than pay to run electricity to your property.

For the preparedness minded, simply having a very basic solar power system (or bigger) provides some peace of mind (at least it did for me). I built an off-grid solar power system which is ‘side-by-side’ with my home’s grid power. I’ve integrated it through ‘transfer switches’ for some of my home’s electrical circuit breakers.

Some people may choose to put together (or at least have on hand) a small system for ‘just in case’. Maybe just several hundred watts to charge several deep cell 12-volt batteries connected to an inverter (for example).

Solar power systems are also becoming popular for RV’s. A few panels up on the roof can make boondocking a bit more comfortable!

>> Renogy Kit – 200 Watt, 12-Volt, 40-Amp, MPPT Controller
(amzn)

A Basic Solar Power System

Without going into great detail, I thought that I would illustrate a very simple and basic solar power system diagram. This one represents the high level building blocks of a stand-alone system. I sketched a diagram:

solar-power-system-diagram

It all starts with a solar panel or panels.

The solar panel (or panels) connect to a charge controller.

The charge controller connects with the panel(s) and the battery (or battery bank, if more than one). It manages the power coming in from the panels as it uses that energy to charge the battery (or battery bank).

The battery (or bank of batteries) also connects to an inverter (DC to AC). The inverter converts the batteries ‘DC’ (direct current) to ‘AC’ (alternating current) for use with typical consumer appliances and devices.

Note: You don’t need the inverter if you’re only running 12-volt DC appliances.

Here’s another solar power system diagram. This one from Renogy.

Renogy solar power kit connection diagram:

Solar Panel connection diagram from Renogy

 
SUMMARY

It’s not terribly difficult to assemble a basic solar power system. Though it does really help to have an understanding of basic electronics and electricity! But even if you don’t have that knowledge, today’s ready-made kits can make it fairly easy. Or, maybe you know someone with some understanding of electricity who might help you. And then there’s always YouTube which surely has plenty of “how to” videos about this topic.

Reference Books for Solar Power System Design

If you’re interested to research this further, it would be beneficial to read up on the subject. Here’s a listing of books which may help:

>> SOLAR POWER REFERENCE BOOKS
(view on amzn)

[ Read: The Four Essentials of Off Grid Solar ]

[ Read: How To Measure Power Consumption During System Design ]

This article has been updated since its original post date to clarify the simplicity of a solar power system block diagram.

[ Read: Solar Power and Energy Requirements – How To Calculate Your Needs ]

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37 Comments

  1. I use a single 200 watt solar panel for off grid truck camping, with a sunny day and a couple of 100 amp hour batteries it gives you charging for electronics, bright LED lamps at night, and fans. Small comforts but very useful if the power is out at home. A great way to learn the basics is to go on line to RV sites.

  2. NRP,
    It’s a “green power system”. Those squiggly lines are the little electrons dancing they way to the battery!

  3. Excellent illustration.
    Even small systems, as described above, will provide usable energy. After that, figure out how much energy (panels/batteries) you’ll need to run what ya want. For me, it was initially a fridge. Think your typical kitchen fridge.

    If that’s what your planning, a smarter way to approach it, is to check out 12 vdc or 24 vdc refrigerators and compare $$. Wish I’d have done that to start with. Any DC appliances will help to make your system WAY MORE efficient. Every time you switch from dc to ac or visa versa, there is substantial loss in the change.

    Took me awhile to get it through my thick skull, power is power. DC appliances work just as well as AC. Starting from scratch, I would definitely incorporate more dc appliances. Oh well, I never was the brightest bulb on the string. Wait I mean LED string.

    1. Plainsmedic;
      You bring up a very good point, and maybe Ken can help us out here, what is the “Typical” efficient divider for converting DC to AC current?
      I’m guessing one would lose 20-30% easily ?????

      1. Outback claims 90 – 93% efficiency. For safety reasons I, personally, would use 85% to calculate my system using Outback inverters. That gives you an acceptable margin, IMHO. The inverters I am using claim 90%. I figured the power availability to be around 80% of the battery drain. Haven’t had a “brown-out” yet. I also have a ‘secondary system’. 500 Watts of PVs, 200 A/Hr of batteries, and 600 Watt inverter. If “System 1” craps out, good ol’ No.2 can pick up the load. They aren’t phase-locked, yet, but working on that.

        1. I currently am using an Outback VFX3648. I estimate that the real world efficiency has been in the 80-90% range. Closer to mid 80’s me thinks.

          There’s a calibration factor that you can fudge with while getting it accurate with remaining state of charge for your battery bank. I had to tweak it from factory settings to be more realistic with what was actually happening. I want to think it was corresponding to 84% or somewhere near that.

          Incidentally, Sol-Ark claims to have the worlds most efficient inverter.

        2. CrowBait,
          I too, ended up with two separate systems. Sounds like you have a very nice system. Are you off-grid or grid-tied? I’d love to be “phase locked,” but doubt it will ever happen. 220 vac is out of reach for a simple country boy, like me. There are other options for some 220 vac
          Solar powered dc deep well pumps, for example.

          The more I learn, the more I realize what I DON’T know. I’ll bet you could teach me a few things.

          1. Plainsmedic…..

            PapaSmurf is correct. Your better effort, IMHO, is to search a lot. Keep track of the prices, and jump on the best deal when it pops up. There’s a lot of places that have good deals on ‘last years’ products. Since you have two systems, I would look at dedicating one to the water pump, acquire a 220VAC inverter, and manually control the water pump. Just watch the line length. Electrical lines, that is. Might even put in a 220VAC GFI, just in case.

            I am not ‘off-grid’, per se. Not really ‘grid-tied’ either. Like Ken, my switchover of the mains is manual. I prefer a real disconnect to the grid. I have lockouts hanging on the wall next to the load center to prevent ‘accidental’ re-connection. I do have a few homemade automated steps in the system. Even an ‘all batteries low’, start the generator box.

            Biggest drawback was I had battery problems and had to re-wire everything to 12 VDC. Half the voltage, twice the current. That really messed up the calibrations. Generator only has 12 VDC output for charging lead-acid batteries v. 24VDC. My bad. I should have seen that. Next step is to get back up to 24 VDC on PVs and associated equipment. Twice the voltage, half the current. Then, if $$$ and time allow, re-wire system to 48VDC and have 24VDC backup system. Won’t be a bad thing unless other people keep winning the lottery.

    2. Plains med ,,,
      12 v. Dc frig v 120v Ac ,,,,better off to run the inverters and 120 v ac as far as power consumption ,been there ,done that ,,,tip ,get the smallest inverter that will run the frig only ,sine wave ofcorse ,
      Out remote ranching we learned to live without a frig ,, I have one in the cabin ,we never use it ,haven’t opened it in at least five years ,,guess we can call it a science experiment ? Ha Ha,,
      With a few exceptions a frig is not necessary to live well ,you just need to think out of the box , and get a good chest cooler ,and. change some of your habits ,,
      We do have a small chest freezer (5cf) run on a inverter ,it gets some use ,handy but if we didn’t have it things would be fine , we had a 21cf but used it so little it was taken out to the shed and used to store horse gain ,,, not the best idea ,mice eat the rubber seal and get in ,,also have a upright 22cf worked fine but it to want out back ten years ago , now got me to thinking what’s in the frig????????should I take it outside to open it????or just keep wondering???
      Tea and chocolate

      1. Oldhomesteader,
        Hmmmm, so even with the inherent losses involved with DC-AC conversion, you had less power consumption with AC? I don’t doubt your word, but my limited experience is different.

        I agree on the right sized inverter. I initially purchased one, much larger than I needed. One of several, minor mistakes I’ve made along the way. In a shtf, I plan to focus all my solar/wind power to run my chest freezer. I can always make ice to help with food preservation in the summer. In the winter, just use nature’s fridge.

        I would think, folks would learn to cook only what they will eat, and eat all they cook. As you know, chest freezer/refrigerators are far more efficient than uprights. The cold air doesn’t “fall out” every time ya open the door. They are not user friendly. In spite of the baskets and shelves, everything tends to end up on the bottom.

        I’m sure a higher elevation and more northern latitude makes a huge difference. I appreciate your posts and wisdom. Please keep them comin.

        1. PlainsMedic,,,, if you do a cost comparison on 12v dc V 120 v ac to set up ,i found the 120v ac the winner ,and the ammonia frig will suffer in hot weather ,i used one for cow meds, and had problems ,, the cost of loss of vaccines more than offset any difference in the long run ,,, i have eleven inverters all have a specific use , 220 v. 5k for well , 120/220 4k for special need , 120v 3k day for cabin ,120v 1.2 k for night lights and deep cooling freezer ,all can run off one battery bank ,all told cost me less than one of the high price inverters

          Over time one learns what works and what doesn’t
          Not putting downs 12v dc. Just think there is some thing better ,
          Tea and chocolate

          1. Oldhomesteader,
            Interesting approach, many different inverters for specific loads. Ya see, I had not considered that. It makes sense to only run as much inverter as ya need.

            Question for ya; You mention sine wave inverters. Are they modified sine wave or pure sine wave. I assume you mean pure sine wave. It is my understanding, for basic applications such as running an electric motor, modified sine wave will work just fine. Pure sine wave is necessary for electronics; computers, radios, amplifiers, etc. I do know that the modified sine wave inverters are significantly cheaper.

            Interesting approach with the many inverters. I’ll have to think on that a while. Thanks Oldhomesteader.

          2. PlainsMedic,,,,,when I first started the off grid journey years ago we had to make our own inverters ,motor drive ,about 40% efficient ,with lots of tinkering,,,,things are so easy now ,,pure sine wave is the only way to go ,modified or square wave will work but the efficiency loss in some things can be very high ,motors will run hot with less power out put ,and not last as long ,electronics most often will buzz at best or die a early death,

            In a past life I had a undershot water wheel ,used a chev truck alt,12v dc to a battery to a inverter 220v ac to battery charger 12 v dc to storage batteries ,to inverter 120v ac to cabin ,,all that because of loss from long run of wire 1400ft ,

            Ended up with a 50percent loss but was able to have power ,in spite of long run ,

          3. Oldhomesteader,
            Thanks for your input on this. Many times the real life application of electrical theory, falls short of what is expected.

            Wow, a water wheel. I’ll bet that was challenging and fun. I’d love to play with hydro-electric. They have really nice stuff for hydro now. I just am not in the right spot to try it.

            I have been fortunate and found some #4 solid copper wire. As ya know, dc takes big wire to go very far. This old wire was salvaged from old oil production applications. I’d hate to pay new price for copper wire.

            I guess that’s why Tesla won out over Edison, in the beginning. My limited experience with dc products has been quite good. Every situation calls for a unique solution.

            What type of physical connector do you use to attach all those inverters to one battery bank? That could be a wiring challenge.

  4. If you decide to go with a 12v battery bank, you can use the wide variety of equipment designed for auto/RV/boat etc.

    For instance, a modern 12v car radio can provide plenty of volume in a home setup! Many LED lights available.

    Be sure to fuse circuits appropriately and keep an eye on bank voltage, since this equipment will continue to operate even when the bank really should be recharged. (An AC inverter will turn itself off under those conditions)

    And yes, a 12v system will require heavier wires than a 24v system or 48v system.

  5. Tell us about Inverters, For instance, If I add more appliances do I need a more powerfull inverter to cope with the extra consumption or is this a daft question ?

    The reason I ask is, There seems to be quite a difference pricewise. So what should we be looking for ?

    1. Ken Dalton Yorkshire UK there is three questions here so I’ll give it a shot. There is running wattage and starting wattage (often MUCH higher) there is ALSO total wattage being used at the same time.

      The inverter is generally rated at it’s maximum rating of power available for use, although some better ones have some “Surge” rating to overcome Starting wattage surges NOT ongoing wattage. Inverters will either shut down to protect themselves or burn out and you need to replace it.

      Load management is choosing what items that will be run together thus maybe allowing a smaller inverter to make do.

      So YES if you add more appliances to be used at the same time you WILL need an inverter sized for your maximum wattage required or it will shut down or worse.

      Or said another way would you use a Mini Cooper with a tow hitch to pull a small trailer OR use it to try to pull out a Double Decker Bus out of the ditch? Personally I’d call a heavy duty tow truck for the latter.

      Hope this helps.

      1. Ken Dalton Yorkshire UK sorry posted too fast, also look at the continuous power rating of your inverter. Inverters companies vary in their advertised standards. Some post only their maximum effort inverter values BUT fail to mention that like hard pushing that Mini Cooper I mentioned will cause it to fail pretty soon.

        Other more honest companies rate at the continuous rating (and generally have more surge capacity). Generally you can find the real world results of inverters at better solar-electric webpages and sometimes in Amazon reviews (once you parse out the “This inverter is awesome” bot messages).

    2. @ Ken Dalton,
      I’m going to keep it simple.

      Inverters range in price from less than $100 to many thousands of dollars. Why? Features, capabilities, design.

      It will require research and understanding of electricity/electronics, and the overall subject in general (beyond the scope of this article and my comment) to get into in-depth design choices.

      However with that said, here are a few notations…

      – Yes, if you add more appliances you will need a more powerful inverter to cope with the extra consumption. (It was not a daft question).

      – “So what should we be looking for?” I cannot answer that. Because it would require knowing your entire installation, expectations, and demands thereof.

      – Though there are many ratings/specifications to consider, the basic primary rating of an inverter is power. Or watts. Choices range from less than 100 up to many thousands of watts, depending on inverter.

      – The first step in the process of determining an inverter is to determine what it will be powering, and how many combined watts those devices might consume.

      ‘Kill A Watt Meter’ — How to Measure Power Consumption (kWh)

      Solar Power and Energy Requirements – How To Calculate Your Needs

      – Inverter design characteristics may be especially important to some people. Some are so called “cheap”, while others are very good. Depends on application (part time power? emergency only? full time power?)

      – There’s lots that I could get into, however it’s probably not what your seeking to discover. That’s why I’ll just keep it simple. More appliances/devices, more powerful inverter ;)

  6. Panel prices,especially used have dropped thru the floor.Cheap chinese solar controllers in the 20-40 dollar range do work.I got agm batteries for 25 cents on the dollar from a hospital battery pullout system on craigslist.You can use wire nuts to connect wiring.Small systems can be very cheap with the biggest costs being batteries and wires.As for racking to mount,that can be done dirt cheap too.One thing I dont scrimp on though is the inverter.

  7. A camper host at the campgrounds I knew used solar, and they put it on the lakeshore facing south and got twice the sun from the reflection in the water.

    1. Very smart application and installation. I love it when people think things through and come up with these “in the field” enhancements.

  8. I bought my panels from Renogy.
    I got “reconditioned” customer returns I don’t know why they were returned.
    But I got the refurbished price that several years ago was about $85 per panel.
    I got 3 100w and 1 80 watt.
    I have a mini system that can power my shop stereo on 1/2 volume for about one single hour
    that cost me about $900.

    The four panels 4 led acid batteries 350w inverter, wiring.. solar charger with backup angle iron/actually aluminum.
    Yea, $900 for only that.

    I run it as a 12v system and not 24 because it’s easier to hook things up to it, just convenience.

    I keep a led 60 watt equivalent light on 24/7

    Just two days ago on *a very cloudy day* I unhooked and tested each panel, all four between 21v and 21.9v

    From this I have the ability to operate any 12v item, and any usb powered item near indefinably and low wattage appliances for limited duration.
    Almost better to use the 900 watt generator.

    On another note
    A mostly useless old 12v car battery with a dead cell and a usb converter is plenty to keep small electronics going for days with no solar panel.
    or your car
    or a 18650 power bank or just the solar panel and the usb converter during the day time.

  9. Minerjim:
    Could you please explain what those squiggly lines are again, it’s been a couple of years.
    Old farts forget stuff ya know.

    Ken, thanks for the revisit.
    We ALL need to remember there are a lot of people who are just starting to build their knowledge about this stuff.

    We ALL need to help as much as we can ,and not do the pointless bickering.

    I for one have learned a LOT from this site.

    1. NRP & Blue,
      You are right about needin’ help with this stuff. The solar industry, newer charge control equipment, battery technology, everything keeps changing so fast. I appreciate everyone’s comments and help, as I have trouble keeping up.
      As for being an old fart NRP,: I’ll try to remember about the squiggly dancing electrons, if you’ll tell us the story again about how the screaming photons crash into the solar panels at the speed of light and make electricity.

  10. The best thing about an off grid solar system is that you don’t become a refuge camping out in your house when the power does go out. Long after every body’s gasoline runs out for their generator, your solar panels quietly produce standby power that keeps you living close to normal. Off grid power has to be paired with a water well, basic refrigeration, and lighting for maximum utilization.

    For those of you that have grid tied solar, consider getting a pure sine 240VAC inverter, small battery and a physical grid disconnect. That way you can trick your grid tied load sharing with your inverter to supply your household loads.

  11. – My Faraday cage holds a 40-watt panel and a 10-amp charge controller, I also have two salvage John Deere tractor marine batteries on a cheap battery maintainer to keep the things charged.

    Back in February, since my stock of firewood was depleted after heart surgery and I hadn’t just gone out and bought some, we ended up using a Kerosun convection heater and hooking the two batteries to the little solar panel.

    The whole house stayed at 62 degrees and we had at least basic lights and radio for the ten days we were without power. I have three inverters from 150-watt to 800, to 1500-watt if I need it. (I do have other inverters of 150 and 400-watt size in the vehicles). Those kept us well-lit and at 62 degrees F throughout the outage.

    We had to minimize power use for the inverters, but we could use even a 1000-watt microwave for a short time. Had the 7.5 kw genset hooked up and ready to go, but got by without having to fire it up.

    Waterline froze and burst, but that’s another story.

    – Papa S.

  12. What a wonderful article and very well done! As PREPPERS we sometimes go over the edge especially when it comes to backup power!!! I love the KISS PRINCIPLE ( KEEP IT SIMPLE STUPID)!!! A small solar panel system is perfect for allowing you to continue to have electrical power when the grid goes down for what ever reason. No it will not run your AC but it will give the basic electrical power you will need to survive with no need for fuel… because you can NEVER store enough fuel!!! Mr SUN has been producing free energy for a long time if we are just smart enough to tap into it! GOD BLESS

    1. never forget it’s all about the batteries, and how much power you can store on the good days, for the bad days

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