Half Cut solar cells and BusBar count to help with Shading

[Donniesuits]

Looking for solar panels (100 Watts) that at some point during the day will receive some shading on part of the panels so I read and learned about Half Cut solar cell panels and this looks like it is good and would help my situation. Next I read about multiple busbar configurations within the cells which seem to also help with shading as well (Busbars in the cells of 10 or greater seems to be the recommendation). So now my question is if both help with shading is there a solar panel that incorporates both these concepts such as half cut solar panels and 12BB or 16BB configuration? When I search online I find 1 concept without mention of the other, half cut panels and no mention of busbar count or 12BB count and no mention of half cut cells. Do they make panels that incorporate both technologies? and if not then is 1 technology better then the other for my situation??

 

[sunshine_eggo]

You are chasing a unicorn. Shading is DESTRUCTIVE to PV production. Even the best panels suffer greatly.

IMHO, you would get better results buying 2X the array of "standard" low cost panels rather than spending a premium on the best shade "tolerant" panels.

Options:

1. Remove that which causes shade.
2. Move array to unshaded location.

 

[Donniesuits]

Unfortunately, neither is an option so as the sun moves from east to west there is a point in the morning where full sun turns into part shade which will move across the panels until around 12:00 - 1pm after which they will begin to get full sun for the rest of the day. Its not a big system and the daily power draw is well below max capacity but I would like to be as efficient as possible so that I get to or as close to 100% recharge in 1 day (power draw is not everyday and most weeks there is no draw for at least 2 consecutive days). So I do have time to recharge over the course of a few days. But to minimize having to count on no power draw days to get back to 100% I am looking at the best panels. Any suggestions on panels? I did finally find half cut and 9BB panels but was wondering if there where better ones with possibly more BB like 12 or 16

JJN 100 Watt 12 Volt Solar Panel 9BB Monocrystalline Solar Module Solar Panels with Half Cut Cells

Allto Solar 100 Watt 12 Volt Solar Panels, High Efficiency 100W Monocrystalline Solar Panels PV Module Power Charger with 9BB Half Cut PERC Solar Cell

I have not heard of either of these 2 companies.

Thanks for the replies

 

[yodamota]

personally, i would get two arrays going one facing south east, one facing south west. seeing as facing due south will be blocked.

south east facing the 10am sun and south west facing the 2pm/3pm sun

 

[sunshine_eggo]

No matter what you buy, you will see drastically reduced performance before 12:00-1:00pm.

It might make more sense to aim your panels so they get more favorable exposure mid afternoon, e.g., if your panels get light from 12:00p-6:00p, aligning the panels with the 2-3pm sun position should increase daily yield.

JJN 100 Watt 12 Volt Solar Panel 9BB Monocrystalline Solar Module Solar Panels with Half Cut Cells

Allto Solar 100 Watt 12 Volt Solar Panels, High Efficiency 100W Monocrystalline Solar Panels PV Module Power Charger with 9BB Half Cut PERC Solar Cell

Not familiar with those companies.

These are simply 100W panels with a 12x3 cell configuration rather than a 4x9. They are slightly more shade tolerant because the panel is divided into thirds rather than halves.

Will it make a meaningful difference in your situation? No. A slight one? Probably. Will they perform like crap in shaded situations, yes. Probably a little less crappy than 4x9 panels.

HOW the shade hits your panels also matters. In landscape orientation, shade a single row, and you've destroyed 1/3 or 1/2 the panel output. In portrait orientation, shading a single row destroy ALL of the panel output.

 

[robbob2112]

This is something that microinverters would help improve, but if you are only doing 100w panels you could just buy 3 times as many panels as you need and make up the difference that way. And not have the expense when one of the little beasties goes out. This means each panel is independant of the other panels so you can point them every which way. But microinverters are expensive.

 

[sunshine_eggo]

This video actually shows a decent comparison between a TRUE half-cut (two panels in parallel in one frame) vs. traditional, shading 1 row in portrait orientation.

The water fountain isn't the most precise, but it gives you a decent idea.

Note that the "half cut" panels you linked will behave EXACTLY light the right panel.

0:12, they have lost about 1/3 of their output with 1/3 of one row shaded.
0:16, left has lost about 1/2 of its output and right has lost about 2/3 of its output.
0:19, left has still lost about 1/2 its output and right has lost all of its output.

Note that the left panel didn't change between 0:16 and 0:19 is because that half of the panel's voltage was too low to contribute any current when the unshaded upper half.

 

[Donniesuits]

So the half cut panels noted above are nothing more than full cells? why is this??

What about these, Both manufacturer state halfcut as well

Newpowa Bifacial 200 Watt 12 Volt Solar Panels, 2 Pieces 9BB Monocrystalline 100W 12V Solar Panel
or
BougeRV 100W 12V 10BB Mono Bifacial Solar Panel

 

[sunshine_eggo]

So the half cut panels noted above are nothing more than full cells? why is this??

Half cut is still a "full cell" in that it can provide about 0.5V of voltage. They're about 1/2 the size of a comparable cell in one dimension.

What about these, Both manufacturer state halfcut as well

Newpowa Bifacial 200 Watt 12 Volt Solar Panels, 2 Pieces 9BB Monocrystalline 100W 12V Solar Panel
or
BougeRV 100W 12V 10BB Mono Bifacial Solar Panel

Mostly same. The Newpowa claim bifacial, so you MIGHT get a boost from the backside in reflective conditions.



Those are just 3x12 or 3x11 panels with rectangular cells. This allows the panel to be split in thirds with bypass diodes vs. the typical split in half on a typical 4x9 (or 4x8) panel with square cells:



This is a lie:



You would actually get output from the right third of the panel boxed in red, not the region indicated by the green.

The below is what you get with what one expects to get with a larger half-cut cell panel:



Effectively two half-size panels in parallel. The dead giveaway is when the wires/junction box are in the middle of the panel and not the end.

 

[Donniesuits]

Thanks, When I see Halfcut I think of the diagram you provided. I did not realize that if the junction box is at the top then the panel is not actually halfcut in the sense that we are speaking regarding the diagram which is what I want. It makes sense that the junction box would be in the middle.