A DIY Off-Grid Solar Power System Overview and Wiring


Hi this is Amy from the altE Store. We’re
going to go over a brief overview of a typical off grid solar electric system. This is just
a small demo, and it can scale up as your needs require. But this will give you a good
overview of the different pieces involved. Now I’ve got a lot of different electronics
and wiring involved, so, what we did is we drew up a schematic, and you can check it
out here. And click on this link and you’ll be able to actually have it up in another window
so you can follow along at home. All right? So, what we have are two 12V solar
panels. They are wired in parallel, so that makes the plusses together and the minuses
together. And that keeps it at 12V. So, I’ve done that within this combiner box. This is
a Midnite PV3 combiner box. And we’re just going to take a quick look inside and remove
the protective face plate. So you can see that we have the plus and minus from solar
panel 1 coming in to, the plus goes into its own breaker. And the minus goes into the negative
bus bar. Then the plus and minus from solar panel 2, the plus goes into a separate breaker,
and the negative goes to the negative bus bar. The output of the breakers are combined
with this included positive finger bus bar. So it slides into the top of the breakers
and that combines the positives. The negative bus bar combines the negatives. And that gives
you your parallel wiring. And so I also have my lightning arrestor that will protect us
from any lightning strikes. And we’ve got the ground going to the grounding bus bar,
the positive going to the positive bus bar, and the negative going to the negative bus
bar. And you can see I’ve also got my ground coming from my racking going into the grounding
bus bar. Now I’ve got the rails grounded through this, and then I have a grounded mid-clamp
from IronRidge, which is taking that ground, across the rail, up to the edges, the frame
of the solar panels. So that is giving me a nice bonded connection through all of this.
I would then go off to a grounding rod, and that would give me my nice earth ground connection.
So I’m coming out of here, in conduit. Now because this is a portable system, I’ve transitioned
to “invisible conduit” here. But know that this is going to be conduit all the way into
the house. So now let’s transition into the house. Great, so now we are inside. So we’ve
gone in conduit all the way into the house. And so what we have here is it is going to
our DC Load Center. Now the DC Load Center is really just a fancy way of saying
breaker box. So we are going to take a look inside our DC Load Center, we happen to be
using a Midnite Big Baby Box for this. So again, we’ve got our combined negative, positive,
and ground, all coming into our DC Load Center. We have it going into a breaker. It’s coming
out of the breaker, into the PV In to the charge controller. My negative is also coming
in, and it’s actually just transitioning right on out. It’s just going in there as a nice
place to land my negative. But it’s going in and then it’s coming right back out and
it’s going to the negative PV In of my charge controller. So then I’ve got my battery out
from the charge controller. I’ve got the plus and minus going into the DC Load Center. The
plus is going to a breaker, and it’s going to be coming out, and going to my positive
bus bar. Now my positive bus bar is going to be going to my battery. So I’ve got the
negative coming out of the charge controller, going to my negative bus bar. And that negative
is also going to be going to my battery. So I’ve got that going from the charge controller,
to the battery. So basically, what these bus bars do, is these give me a nice easy way
to connect everything to the battery. So I only have one connection to the battery,
because that’s connecting in to my bus bars. So anything I need to connect to the battery,
I can just connect to the bus bar, through a breaker. So I have going from the positive
and the negative, I’m actually going to a cigarette outlet. This is very common to use
for a DC connection. So if I have anything that would plug into my cigarette outlet in
my car or an RV, I can just plug in and run it right off the battery. I’ve got a fuse
in here, so I do have my over current protection, or If I wanted to, I could have put in another
breaker and I could have gone through there. So, I have that DC load. Now I also am going
from the positive bus bar, to another breaker, and I’m going out to the DC input of my inverter.
I’ve got a 12V inverter. So I’ve also got the negative coming from the negative bus
bar, which is just acting like the battery, going to the negative of the inverter. And
I’ve got my ground. So, the inverter is turning that into 120V 60Hz pure sinewave, because
I’m in North America. If I was someplace that used 230V 50Hz, I would just use a different
inverter for that. So it’s creating the AC power for me. It’s going to an AC breaker
box. For this I’m just using a Midnite Baby Box, but if you’ve got a lot of AC loads,
you would have a bigger AC breaker box. So I’m going through my breaker, going out to
an AC outlet, where I have my lights! So I have got the light going through a breaker
to the inverter, through a breaker, to the battery. And I’ve got a nice meter, Morningstar
happens to make both this inverter and the charge controller, and they’ve got a meter
that I can actually connect to either one, and it will read different settings and different
measurements based on what it’s connected to. So that is just an overview of this demo
system. We’re going to do a whole bunch of other videos based on this demo, so stay tuned.
And I hope you enjoyed our video. You can watch more here, and check out more of us
at, where we are making renewable do-able.

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15 thoughts on “A DIY Off-Grid Solar Power System Overview and Wiring”

  1. Francis Opoku says:

    cool video. thanks Amy

  2. Mark Cole says:

    Thank you Amy for showing how a solar system is wired. I have seen many of your videos and they are very informative. I notice in the back ground a picture of a RV roof. I'm in the planning stage for hooking up 6 160 watts 12 volt panels for my motorhome. Is a Lightning Arrestor useful in a RV. If so, would I ground it to the chassis of the motorhome?

  3. Geof Santiago says:

    Thanks so much for sharing this over view now I am confident that I can make it work.. great job!

  4. OFW DAD says:

    i think ypu should include sizes of wires used from one point to another..

  5. akash kodu says:

    Can I connect the controller dc load output directly to the inverter battery terminal input?

  6. Nunya Dibness says:

    Can I use 16ga Speaker Wire to wire my 25 watt solar panel to my controller?

  7. Ali ali says:

    How Do I make a drawing like the one you'r using?what software do that for me?

  8. David Fairfield says:

    i have looked everywhere but the right location but i want to over size a hybrid system but want to max out the current to charge batteries faster. but come summer im worried it be too much current for the inverter. any ideas how to limit it so winter its good and summer its limited and due to weather thats unpredictable it needs to be auto. any ideas?

  9. Islam Nasr says:

    good job
    can you make videos how to design water pumping system?

  10. Jess Stuart says:

    Nice demo system! Is panel mismatch a concern for these kinds of small 12V panels? Are diodes ever needed?

  11. Schrimpieman says:

    I understand the concept of breakers and fuses to maintain over-current safety factors within electrical systems, but I have question(s) as to why breakers are needed between the PV array and the charge controller. Suppose a random sample PV panel is operating at perfect standard test conditions with (Current @ Short Circuit) Isc = 7.9 Amps and (Current @ Max Power) Imp = 7.4 amps. I'm hypothetically using a 10-Amp breaker to allow the 7.4 Amps (at MaxPowerPoint) flow into the charge controller. Even if there was a short circuit, the current flow would only reach 7.9 Amps because that's the PV panel rated output. The current flow never reaches 10 amps. Does the breaker sense a voltage drop to near zero and trip due to the combined effect of current flow at such low voltage?
    Breakers are obviously required in circuits where (such as) batteries are the power source. A substantial battery bank can release hundreds or thousands of amperes in a short circuit condition. But PV panels current output is limited simply by their mode of operation. How can a Isc condition through a PV panel of 7.9 amps trip a 10-Amp breaker? (I've read that PV breakers are specifically engineered for PV systems. In other words, don't use regular breakers for PV systems).
    But I'm still stuck on the fact that the PV panel never exceeds 7.9 amps. How can a 10-Amp breaker trip under short circuit?

  12. Ramon L says:

    Very educational. You know your subject very well. thank you so much for making this video series.

  13. Gary Sondh says:

    Good video but this is old circuit – new micro-inv are different and slightly different wiring.. integrated negative etc..

  14. David Self says:

    You are awesome. Great video!

  15. MEC Solar Shanlee says:

    I am tried in saying Thanks to you dear and dearest teaching units….
    I Love you all. 🎖🎖😘😘😘

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