Bifacial Solar Panel - power from rear?

[dgadee]

I've just bought a Renogy solar panel which is supposed to provide power from the rear of the panel. I thought that would be useful to get light reflected off the sea.

However, a quick query from Renogy says: "The usage method you mentioned is indeed similar to the top of the panel where small amounts of shading on the top of the solar panel can reduce its output." Not much more info than that! Anyone looked into these bifacial panels - are they worth the bother of ensuing no supports under the panel get in the way of light?

 

[Sea Change]

I've just fitted three 450w bifacial panels.
I didn't specifically choose them for that feature, they just happened to be the best deal available. I've fitted them to my stern arch without really worrying about whether underneath them.
I have no idea whether the bifacial feature is adding anything, but I am extremely impressed with the panels. Maybe it's just because I had secondhand panels on my old boat but I'm really very, very impressed with them.

 

[vyv_cox]

I have one on my motorhome where there is no chance of light from the rear. Bought on price/size. I have seen them installed as a garden fence although vertical installation seems inefficient.

 

[dgadee]

I have one on my motorhome where there is no chance of light from the rear. Bought on price/size. I have seen them installed as a garden fence although vertical installation seems inefficient.

Yes, it was price and size which got me, but then it sounded as though there might be a few more electrons going about.

How do the two faces interact?

 

[Sea Change]

Yes, it was price and size which got me, but then it sounded as though there might be a few more electrons going about.

How do the two faces interact?

My understanding is that they simply don't put a plastic backing on the panels, it's glass both sides. So it's the same silicon wafers but both sides are exposed.

 

[dgadee]

My understanding is that they simply don't put a plastic backing on the panels, it's glass both sides. So it's the same silicon wafers but both sides are exposed.

Yes, just looked at it and that's what it looks like. There is a narrow central lane with two wires and connectors coming off it. Bit of a swizz to call it bifacial!

 

[lustyd]

seen them installed as a garden fence although vertical installation seems inefficient

The data says otherwise. Vertical panels lined north to south (so facing east and west) get two peaks a day which add up to more overall power than a south facing panel which gets one peak a day at noon. The vertical also benefits from a longer apparent day since it faces the horizon and gets lower angled sun.

 

[geem]

We just swapped 4x180w type P solar panels that were 7 years old for 4x250w bifacial type N solar panels. The 250w panels are only slightly larger than the 180w panels and they fit in the same locations on the guardrails as my old panels. We have been in the boatyard for a week, and launched earlier this week. The performance of the bifacial panels in the vertical position is very impressive. Early morning sun would be full on the front of the port side panels but the starboard panels nearly performed as well with sun on their rear.
For a boat left on a mooring with bifacial panels on guardrails, left vertical, I think the bifacial aspect would add some very useful output.
I did plenty of research on bifacial panels before I installed them. The reflection over water is only worth about an extra 6% output. Although this is useful, it's not huge. Mounting bifacial panels on a solar arch would likely see this extra performance. Mounting bifacial panels on a guardrail will likely see considerably more since you can get almost full sun on the rear of one set of panels for part of the day. Even when the sun was fully infront of the boat, on cloudy days with vertical panels, the output is surprisingly good.