Something wrong..

[Truck driver]

While you likely not reach more than 75% of panel ratings except in rare occasions I do see one aspect of the panels placement that can reduce output. Being placed on the ground allows the bottom edge to easily have things shade it. Your two pictures illustrate this of snow in the Winter and grass in the Summer. It does not take much shade covered areas to really reduce what you can get.

The panels have seen just over 1000w.. If they could average that I'd be happy. 800w or less is not satisfactory. haha. That's 50% or less. Yeah.. your point makes sense and I try and keep that lower edge trimmed.. but even a few blades of grass shouldn't affect it that much. I added more tilt to them yesterday evening.. they're at 45% tilt. system is getting 70w now.. and that's mainly from the front panel.

 

[Truck driver]

2S2P?

I would suggest trying mounting the panels a bit higher. You could use your trailer for a simple mount structure to lean onto and retain the area occupied and the panel's angle while keeping the panels dry and away from near-ground shading.

View attachment 148749

Edit: missed the part with PV voltage screenshot.

I can do that. I'll find some lumber or blocks to lift them. Thanx.

 

[Truck driver]

The second pic in post #3 shows that you have 2 panels wired in parallel, twice. There are 4 wires going into the RV from what i can see.
Are these 4 wires then connected in parallel again in the RV?

Is this also connected in parallel to the 4 panels on the RV side?

I think we'd need to know exactly how you have these wired to recommend a better/best configuration. With so many parallel connections, you may be doing some serious voltage clipping (a result of connecting mismatched panels/arrays in parallel).

They're wired in 2s2p. left 2 panels: both negatives are connected and both positives are connected then into a 2-in-1 branch connector which go up to the extension cables and back into another 2-in-1 branch connector and then down to the controller.

 

[Truck driver]

I can do that. I'll find some lumber or blocks to lift them. Thanx.

Yes. 2s2p. I found some lumber to lift them off the ground but the tilt on the panels is too much and they slide off. Need to pound some rebar stakes into the ground. Guess I'm heading to town.

 

[Truck driver]

The second pic in post #3 shows that you have 2 panels wired in parallel, twice. There are 4 wires going into the RV from what i can see.
Are these 4 wires then connected in parallel again in the RV?

Is this also connected in parallel to the 4 panels on the RV side?

I think we'd need to know exactly how you have these wired to recommend a better/best configuration. With so many parallel connections, you may be doing some serious voltage clipping (a result of connecting mismatched panels/arrays in parallel).

Yes.. into the branch connector.. Panels are identical... Ugghh.. This just triggered a thought. The front panel is 290w.. other ones are 400. I have a 2nd controller ready to be connected.. just need to pull some new 8ga wires.

 

[Truck driver]

Yes.. into the branch connector.. Panels are identical... Ugghh.. This just triggered a thought. The front panel is 290w.. other ones are 400. I have a 2nd controller ready to be connected.. just need to pull some new 8ga wires.

Disconnected now.

 

[Truck driver]

So.. I got to thinking about the 10awg wires that go to the controller and go up to the fridge vent.. Why not disconnect the MC4's that connect to the panels and connect them directly to the controller. So I climbed up top and removed them and then first thing in the morning.. plug them into the controller and see if the wattage increases or not. Then I'll know if that's what has been bottlenecking the panels or not. Wish me luck..!

So I rotated the 150\45 controller, connected the battery wires, edited the name and updated the firmware. Now I'll plug in the PV in the morning and watch the results..

 

[MisterSandals]

They're wired in 2s2p. left 2 panels: both negatives are connected and both positives are connected then into a 2-in-1 branch connector which go up to the extension cables and back into another 2-in-1 branch connector and then down to the controller.

2 in parallel and put in series with another parallel pair is 2P2S.

If you add this2P2S in parallel with another pair, your voltage of your 2P2S string will be clipped to that of the lower voltage front panel.
This is where you are leaving a lot of watts outside.

 

[MisterSandals]

This just triggered a thought. The front panel is 290w.. other ones are 400. I have a 2nd controller ready to be connected.. just need to pull some new 8ga wires.

If you provide the panels specs (Vmp and Imp) for the 4x 400W panels and the 290W panel, its likely we can determine the optimal way to wire your array. I'm pretty sure your 2P2S in parallel with a single panel is very sub-optimal.

Theoretically, these 5 panels would likely produce:

((2 x Imp of 400W panels) + (Imp of 290W panel)) x Vmp of the 290W panel

So you are likely clipping at least 2 of the 400W panels

 

[SamDeleted]

If you provide the panels specs (Vmp and Imp) for the 4x 400W panels and the 290W panel, its likely we can determine the optimal way to wire your array. I'm pretty sure your 2P2S in parallel with a single panel is very sub-optimal.

Theoretically, these 5 panels would likely produce:

((2 x Imp of 400W panels) + (Imp of 290W panel)) x Vmp of the 290W panel

So you are likely clipping at least 2 of the 400W panels

So the 290w panel is dragging the others down

 

[Pi Curio]

2 in parallel and put in series with another parallel pair is 2P2S.

If you add this2P2S in parallel with another pair, your voltage of your 2P2S string will be clipped to that of the lower voltage front panel.
This is where you are leaving a lot of watts outside.

Good observation.

 

[Truck driver]

2 in parallel and put in series with another parallel pair is 2P2S.

If you add this2P2S in parallel with another pair, your voltage of your 2P2S string will be clipped to that of the lower voltage front panel.
This is where you are leaving a lot of watts outside.

I agree.. which I unplugged the front panel late yesterday. I have a 2nd controller to connect. It's just a matter of pulling some new wire for it.

 

[Truck driver]

If you provide the panels specs (Vmp and Imp) for the 4x 400W panels and the 290W panel, its likely we can determine the optimal way to wire your array. I'm pretty sure your 2P2S in parallel with a single panel is very sub-optimal.

Theoretically, these 5 panels would likely produce:

((2 x Imp of 400W panels) + (Imp of 290W panel)) x Vmp of the 290W panel

So you are likely clipping at least 2 of the 400W panels

Here they are.. there are four 400w and six 290w panels. Four of the 290's are in the bed of my pickup and not here. Need to build\buy some ground mounts and connect them all. This place is very shaded for most of the day.. but between 1-4 pm it's direct sunlight. On a side note: I only recently plugged in the front panel for some morning sun.. It was helping and hurting. Helping becuase it would capture some sunshine for a couple of hours and then when the sun rose high enough for the MAIN panels to capture.. it would then be "clipping" due to the smaller panel.

 

[Pi Curio]

@Truck driver

Suggestion for the array optimization, in regards to the 4x400W side panels array you got.

I'd suggest the following 2s2p configuration. With the assumption you will raise these panels above the ground(very important), given the shading you got I'd recommend installing the panels in landscape orientation and letting the panel's half-cut design(aka duo panels/two halves) do its thing.

In the drawing below in Landscape panel orientation, 2s2p configuration, your array will gain 4 columns of independent production, and the two panels on the right side(red) will not impact the production of the two panels on the left side(blue).

The blue panels are in series together, same goes for the red panels in the drawing. The two series, red and blue, are then connected in parallel.

 

[MisterSandals]

36.4V 7.97A 290W
41.1V 9.74A 400W

400W 2P2S produces 73V 16A

When in parallel with 290W panel, in theory it should produce 25.74A at 41.1V = 1058W (far less than the 4x 400W)

there are four 400w and six 290w panels. Four of the 290's are in the bed of my pickup and not here.

1600W + (6 x 290W) = 3340W
Assuming 12V battery: 3340W / 28V charging = 119A max charging capability

What is your battery bank? Wondering how much charging amps it could safely accept when/if all panels producing.

Conversely, with as much shading as you describe, a 100A SCC may be enough for these 10 panels if configured properly.

Before going thru the effort of doing the possible math scenarios, are there physical limitations of how these panels can/will be arranged?
Will the 4 panels be mounted together as well as the 6 panels all together? Or will some be on RV roof, some on ground mount...?

 

[Truck driver]

@Truck driver

Suggestion for the array optimization, in regards to the 4x400W side panels array you got.

I'd suggest the following 2s2p configuration. With the assumption you will raise these panels above the ground(very important), given the shading you got I'd recommend installing the panels in landscape orientation and letting the panel's half-cut design(aka duo panels/two halves) do its thing.

In the drawing below in Landscape panel orientation, 2s2p configuration, your array will gain 4 columns of independent production, and the two panels on the right side(red) will not impact the production of the two panels on the left side(blue).

The blue panels are in series together, same goes for the red panels in the drawing. The two series, red and blue, are then connected in parallel.

View attachment 148901

They ARE currently in 2s2p config.. It's 2:48 pm now..

 

[MisterSandals]

They ARE currently in 2s2p config.. It's 2:48 pm now..

Your pics show you have 2 panels in parallel (twice), connected with Y connectors from the panel leads. This is 2P.
If you have these parallel pairs then connected in series, around here anyway, that becomes 2P2S.

But maybe i'm seeing the pics wrong...

 

[sunshine_eggo]

This has been really interesting. A real shit show for me to follow and decipher...

I couldn't make heads nor tails of the wiring pictures, and this:



SCREAMS the array is either in 4P or the 290W in parallel with 2S is forcing a lower voltage. The only reason I think the latter is because there was ONE day at 88V.. makes me think you disconnected your 290W panel that day. This value should be your Voc first thing in the morning before it starts drawing current. Here's my 3S array:



I'll admit your solar may be so bad that it's always trying to pull current and you're just not seeing Voc like I do.

VRM advanced tab can be really useful too:


On a 12V system there is zero reason to go higher than 36Vmp unless you need to stay under a current limitation, i.e., wiring or the 70A limit on the MPPT input.

This is further bolstered by the fact that solar appears to be absolute garbage except for the 3 afternoon hours. If there's morning sun to be had, nab it with a 5P configuration. Yes. The 290W will cause some small losses, but the MPPT conducts a sweep every 10 minutes. It's going to figure out the 4 larger panels will contribute more closer to their Vmp than the 290W panel's Vmp. Furthermore, mid-day, the front panel will have very little to offer besides Voc. The MPPT will figure out where to get the max output will be. Since the 290W Voc is higher than the 400W Vmp, there's no risk of backfeeding and the operating voltage

This should optimize your production. The only issue is you need to be able to handle 50A in the wire down through the roof.

Alternatively, get another 290W panel out of the back of the truck, wire it 2S with the other 290W and join it to the 2S2P 400W for a 2S3P array.

 

[Truck driver]

What I love most about that RV picture with the panels, is the tiny solar panel for the camera right next to its big brothers!

Your too funny.. So.. How many do you see..? and how many security cameras do you see..

I have four of them. 1 in the front window and 3 in the kitchen window. I love these things.

https://www.amazon.com/Flyhoom-Camping-Rechargeable-Remote-Control/dp/B07THY3GK9?ref_=ast_sto_dp&th=1&psc=1

 

[Truck driver]

Your pics show you have 2 panels in parallel (twice), connected with Y connectors from the panel leads. This is 2P.
If you have these parallel pairs then connected in series, around here anyway, that becomes 2P2S.

But maybe i'm seeing the pics wrong...

While the sun is still up.. I'll go lift up the panels and make a short as possible video. Well.. I have a video but this site doesn't allow them. So I sent the video to my YT channel..