Bifacial solar panel discoloration on back side

[Watts Happening]

Without further context, would the differing colors on the back side of these modules bother you, or be an indication of an existing or upcoming issue with the panel as a whole? They are used (obviously), but in theory not all that old.

You’ll notice darker modules, and ones that are lighter, maybe “dull”. I want to make sure I have realistic expectations, as well as not overlook an obvious sign of upcoming failure.

 

[shadowmaker]

I'm pretty sure the backside of my bifacials are polycrystalline even though frontside is shingled monocrystalline. Yours have the same bluish tint on them.

frontside


backside at golden hour.

 

[Watts Happening]

I'm pretty sure the backside of my bifacials are polycrystalline even though frontside is shingled monocrystalline. Yours have the same bluish tint on them.

frontside
View attachment 165253

backside at golden hour.
View attachment 165254

So you’d call that normal/par for the course?

 

[shadowmaker]

So you’d call that normal/par for the course?

Yep. Maybe some more expensive panels with better bifacial factor (mine are only ~75%, so 700W front, 500W back) have monocrystalline backside.

 

[timselectric]

If you are referring to the variation in the blue color. It's not an issue. It's mostly just how light is being reflected.

 

[Watts Happening]

If you are referring to the variation in the blue color. It's not an issue. It's mostly just how light is being reflected.

Weird, in my garage it is very obvious regardless of angle. But hey, I’ll take it as a good thing.

 

[timselectric]

Areal view of my roof, on a dewy morning.

 

[Watts Happening]

Areal view of my roof, on a dewy morning.

View attachment 165299

A) I'm jealous, fire code blocks me from doing anything near that and I hate it.

B) You drilled holes in your solar panels?

 

[timselectric]

You drilled holes in your solar panels?

My OCD wouldn't stand for gaps in the panels.
Those two are bad panels, just keeping everything uniform looking.

 

[Watts Happening]

My OCD wouldn't stand for gaps in the panels.
Those two are bad panels, just keeping everything uniform looking.

I understand the pain.

 

[ghostwriter66]

I'm pretty sure the backside of my bifacials are polycrystalline even though frontside is shingled monocrystalline. Yours have the same bluish tint on them.

frontside
View attachment 165253

backside at golden hour.
View attachment 165254

I have NEVER seen vertical panels in my life ... totally bizarre ... Here in South TEXAS, USA our summer inclination is literally HORIZONTAL FLAT ...

 

[shadowmaker]

I have NEVER seen vertical panels in my life ... totally bizarre ... Here in South TEXAS, USA our summer inclination is literally HORIZONTAL FLAT ...

Yep, I don't think this is something you should consider, but in here, near the arctic circle, vertical seems to be the way to go at least in the winter. Adjustable tilt would be nice for summer, but what I loose because of vertical tilt, I almost gain with better bifacial yield. Also we have over 19 hours of sun up here around summer equinox, so plenty summer production anyways.