Alright! we’ve got the panels mounted and now we’re ready to connect the wiring that brings the power down to our charge controller which is located on the ground. We’re going to be using this BX style wire which is just twelve gage wire with a wrapping of sturdy aluminum on the outside to protect it from the elements. Typically used in household wiring, pretty common at your home improvement center, twelve gage is adequate for a small system like this. Black wire for our positive connection, the white wire will be negative.
It’s also called the neutral in an ac system. but for this we can use the white wire as negative, and then the green will go to our frame as a ground. So, we’ll just strip a little bit of wire off here. We’ve got our DC wires already marked coming from the panels. Red, positive and white is negative. So we’ll follow that here, again, and strip these wires down. Special wiring comes out of these panels. It’s USE rated versus THHN for instance. And this USE wire is UV stabilized so it can actually be out in the sunlight for many years without.
Degrading. we’re using the shielded wire here could be in different styles of conduit or even a UV rated wire for a small installation like this. And your bigger grid type connections, all this can be in conduit and the wire choices would be a little more limited because of the high voltages concerned. But here, twelve to forty volts, we’re not really as concerned with that as we might be. Still, it’s nice to have everything solid. We’re going to use our linesmen pliers here to get a nice solid twist on our positive wires and a little wire nut on top of that, snug.
It down. we’ve got our negative wire here, and you notice i didn’t strip these both at the same time. Even through it’s only 40 volts, you can still get a pretty decent shock off of these panels. So, it pays to keep the wires separate. In fact, at the other end here, we’re not quite ready to make this connection, we should connect down at the bottom first before making this wire completely hot, just for safety. So now, let’s leave this for a moment and go down and wire up our charge controller here in the laundry room.
How to Wire Mismatched Solar Panels in series and parallel
Hi this is amy from the alte store. You might have seen the series of tutorials that we’ve been doing where we’re showing different ways to wire panel that are mismatched. So different watts, different amps, different volts. And depending on what is different, there’s different ways that you should wire it; in series or parallel.
So you can check out the whole playlist we did showing that. Now one of the things that we did show was that if you do have two different solar panels, two different sizes, the best way to deal with it, with charging a single battery bank, is for each of them to have their own charge controller. So we did do a tutorial on that, you can check that out. But another option is, you could take multiple panels and wire them together to equal the.
Same output as the other mismatched panel. For instance, I have a 100W 24V panel, and I have some 50W 12V panels. So what I can do, is I can wire my two 12V panels in series, plus to minus, and then I can wire it in parallel with my 24V panel, and I don’t have to worry about the lower voltage 12V panels pulling that voltage down, like it did when I just had a single one. So this is going to show you a great solution.
So you can take a look, right now i just have my 24v 100w solar panel connected. I have my new handy dandy fancy schmancy meter going on here. So I’ve got 30.7V coming out of that solar panel. It makes sense, the Vmp is about 36V and it’s pretty hot out right now, so it makes sense. And I have 2.4A coming out. Again, that’s right around what I’d expect to see.
The imp is 2.78a. so that’s the maximum power current, so that’s generally what you’d see when it’s connected, and again I’m not at perfect angles, I’m not at perfect test conditions, so that seems about right. So, what I’m going to do is show you that I’ve got that 24V panel connected through an MPPT charge controller. In this case it’s a Midnite Kid.
And it’s going to my mk battery 12v battery. So the reason I’m doing it with an MPPT is because I’m going 24V down to 12V. And we’ve done some tutorials showing what happens if you use a PWM charge controller in that case too, so you can check that out as well. So you can see that the output of the charge controller going into my battery is 12.9V and 5.45A. So what it did was it took that higher voltage, it dropped it down, and it.
Increased the current to maximize the output. So you can even see on the meter that I’ve got basically 74W going into the charge controller, just about 70W coming out. So that makes sense, I’ve got a little bit of losses through the charge controller. You would expect that with any equipment, you are going to have some losses. So now let’s see what I get when I just wire my single 12V panel to the same charge controller.
Ok? so hold on a sec. Alright. Now with a single 50W 12V solar panel, the Vmp is 18V, so that’s maximum power volts, that’s what you’d expect to see with it connected at its maximum output. And 2.78A Imp. So that’s the same current as that 100W 24V, but the 12V panel has half the voltage.