Mix and Match different panels?

Hello all. I'm building out a solar system for my sprinter van. I'm starting w/ 3 100 watt HQST mono panels, and I want to get more than that up there (I think 400-500 watts total would do me well) but there isn't room on my roof for another 100 watt panel (26" x 36"). HQST makes a 70w panel that's long and skinny (16" x 47") that would fit up there nicely, as well as 50w panels that are obviously smaller and could fit on either side of my fan.

My questions are: Are there any issues w/ combining different sized panels in the same solar array?
Are there any issues w/ trying to put 5 or 6 panels into the same solar array (3x100, 2x50 and 1x70 for example)?
Is there any reason why I can't/shouldn't use a different brand or type of panel in the same solar array?

I'm trying to mimic Will's blueprint for this system that charges off the alternator as well https://www.mobile-solarpower.com/simplified-400-watt-fewer-wires-and-alternator-charging.html but for the reason I already stated, I can't just use 4 100w panels. I do plan on using the renogy 50 amp dc-dc controller in the link fwiw.

I really appreciate any help and advice. Thanks!

I did a series of videos showing how best to wire mismatched solar panels. Because yours all probably have around the same volts, but different amps, they would be best wired in parallel.

Solar cell is nothing but battery. Parallel connection adds current and series connection adds voltage. Different size solar panels around the same voltage can be better matched in parallel connection to get the most of power. It could have been interesting to measure the voltages at each panels

SolarQueen said:

did a series of videos showing how best to wire mismatched solar panels. Because yours all probably have around the same volts, but different amps, they would be best wired in parallel.

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Might not make a difference with a van, but for my RV paralleling runs meant wire thicker than I wanted to work with.

I’m finding parallel really limits me with my controller, because amps and wire size really creeps up on me quickly. I had originally wanted my six 100 watt solar panels wired in series to feed my charge controller, but with my runs, wiring size exceeded 10 gauge, which became more challenging to work with, so I changed this to 3S2P and that kept my wiring at 10 gauge. Luckily my MPPT controller lets me put up to 100 volts in series.

I have a set of four panels that have a measured short circuit voltage of 22.5 VDC and measured short circuit amps of 6.5 that the manufacturer says can only be put in parallel, and I’m wondering what my limitations will be if the amperage flowing through that circuit is close to 26 amps. These are supposed to be ground panels, and such a high amps means the cable size I want will probably be shorter than I’d like or thicker than I‘d like.

MBR said:

Its also bad to post on a repost. Lol
Just report the post for deletion.
He posted the same question 3 times!
What if Everyone posted their question 2 or 3 times?

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I'm sorry. I'm new here and to forums in general. is reporting me for it really necessary? is doing 3 posts really "spamming"?

SolarQueen said:

I did a series of videos showing how best to wire mismatched solar panels. Because yours all probably have around the same volts, but different amps, they would be best wired in parallel.

Click to expand...

This is very helpful thank you!

PaulW said:

Again, I'm new here and didn't realize posting in 3 different threads would all go into 1 main thread or be a big deal. I won't do it again.
And I did get fast answers from some helpful people (i.e. not you) but it was after my infamous 3 posts were already published.

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One post would have been answered at the same speed and time.
SolarQueen answered your post comprehensively so there was no need to duplicate what she said.

MBR said:

One post would have been answered at the same speed and time.
SolarQueen answered your post comprehensively so there was no need to duplicate what she said.

Click to expand...

Got it. Have a good day!

chrisski said:

I have a set of four panels that have a measured short circuit voltage of 22.5 VDC and measured short circuit amps of 6.5 that the manufacturer says can only be put in parallel, and I’m wondering what my limitations will be if the amperage flowing through that circuit is close to 26 amps. These are supposed to be ground panels, and such a high amps means the cable size I want will probably be shorter than I’d like or thicker than I‘d like.

Click to expand...

If you know the cable distance just calculate the voltage drop for your Vmp, amps and distance.

I had been delaying calculating this. I did not want to see the results since the manufacturer said in parallel only. Using the manufacturer's specs of 18 volts and 6 amps and accepting a % loss:

Parallel, 18 volts, 24 Amps
To run ground panels to the farthest point of my RV would be 20' away and require round trip of 40' of cable, my cable would need to be 4 AWG.
To run ground panels to the closest point of my RV would be 5' away and require round trip of 10' of cable, my cable would need to be 10 AWG.

Series, 72 volts, 6 Amps
To run ground panels to the farthest point of my RV would be 20' away and require round trip of 40' of cable, my cable would need to be 16 AWG.
To run ground panels to the closest point of my RV would be 5' away and require round trip of 10' of cable, my cable would need to be 22 AWG.

So for my instance, provided I have an MPPT charge controller that can handle this, I need to put panels in series, especially if I'm limited in the direction I park and will need to string the portable panels to the far end of the RV to get them in light.

Since calculating this, I have taken a good look at the panels and popped the Junction box cover, and the J-Box only had a diode and no wiring, so I will put these in series, void the warranty, and that way I can make wire size manageable when balanced with loss.