Hi this is Amy from the altE Store.
You might have seen the series of videos 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 video 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 videos 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.
Half the volts but same amps.
So if we look at what we're reading, we've got 14.8V going into the charge controller,
2.56A coming out of the panel into the charge controller.
And then into the battery 12.8V into the battery and 2.65A. Alright, cool.
So you can see we've got twice as much volts and so we are going to see what happens if
we wire the two solar panels, the two 12V panels together in series.
OK?
OK.
So now we have these two 12V panels wired in series, with the plus to the minus, and
we've got those measuring through the charge controller.
So we have 28.6V going in, hmmm, that's very similar.
And 2.27A, again, very very similar to that one single panel.
So, wiring these two together really turned it into basically 100W 24V panel.
So now let's wire them in parallel.
There's a couple different ways you can wire them in parallel, we've done videos on both
using a combiner box, which is a great way to make sure you've got breakers between both
strings, or if you've just got a small system that's less than say 30A, you can use a coupler.
So you can check out the videos we did on both of those options.
So I'm going to wire the two sets in parallel and we'll see what we get.
OK, so we've got these two solar panels wired in a string of two, two in series, wired in
parallel with a single string of the one 24V panel.
So we've got two parallel string, one is a string of two 12V and one is a string of one 24V.
They both make 24V.
So now we are going to see that because we wired them in parallel, the volts stay the
same, so we look we are right around 30.8V. That's right around what we were getting individually.
And we are at 4.47A. Now that is twice as much as we were getting with them each on
their own.
So we've doubled the current by wiring in parallel, kept the voltage the same, except
on this string where we doubled this voltage.
So if we look at it going through the MPPT charge controller to our 12V MK Battery battery,
we've got 13V going into the battery and 10.14A because the MPPT dropped the volts and raised
the current, so we are not losing any power.
So now we've pretty much doubled our power going into our battery, because we were able
to wire these efficiently to make them so that the two parallel strings matched each other.
I hope this was helpful.
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And don't forget to go to our website at altEstore.com, where we've been making renewable do-able
since 1999.