[SOLD] Bifacial 405W Monocrystalline Solar Panel

[BenBowSirocco]

Hello,

I would like to order a pair of 405W 48V Bifacial Monocrystalline Solar panels for my new stern arch, but the company I am ordering from has a 4 panel order minimum.

I am seeking someone to go in on the order with me in order to meet the minimum order.

For $600 dollars you receive two (2) bifacial 405W Monocrystalline solar panels for a total of 810W.

For those who do not know what a bifacial solar panel is, it is a panel with a clear back- just like the front- that allows light to be received by the photovoltaic cells from both directions.



The reason to choose bifacial panels for your boat are many, especially if mounting them to an arch.

For example, we all know that the glare off the water is sometimes worse than the direct sun, especially in the low/glancing light conditions of late afternoon- a bifacial panel takes advantage of this by receiving light on the bottom/back of the panel just as effectively as the front. Also, even in direct sun, the ambient light and the reflected light off the water still strike both sides of the panel, dramatically increasing its efficiency.


Please see the linked photos of the panels marketing materials to verify that it will meet your quality standards and fit your application.
If you would like more than two panels- thats great! Since we are already paying for shipping, adding panels is easy and I can give you totals for as many as needed.

https://drive.google.com/file/d/1Hjy...ew?usp=sharing
https://drive.google.com/file/d/1Xta...ew?usp=sharing
https://drive.google.com/file/d/1VPO...ew?usp=sharing
https://drive.google.com/file/d/15bC...ew?usp=sharing
https://drive.google.com/file/d/1-J3...ew?usp=sharing




I will receive the panels at a commercial loading dock in St. Petersburg Florida, inspect the packaging for damage at reception and bring your two panels to a previously agreed location for pickup.



I would prefer a deposit of half of the money up front and half upon exchange of the panels. Delivery is limited to a 1/2 hour drive time from St. Petersburg Florida- delivery at longer distances is mildly negotiable for a fee- but I am really not very interested in driving across the state.



PM me with any questions or interest.

[redneckrob]

Originally Posted by BenBowSirocco

Hello,

I would like to order a pair of 405W 48V Bifacial Monocrystalline Solar panels for my new stern arch, but the company I am ordering from has a 4 panel order minimum.

I am seeking someone to go in on the order with me in order to meet the minimum order.

For $600 dollars you receive two (2) bifacial 405W Monocrystalline solar panels for a total of 810W.

For those who do not know what a bifacial solar panel is, it is a panel with a clear back- just like the front- that allows light to be received by the photovoltaic cells from both directions.



The reason to choose bifacial panels for your boat are many, especially if mounting them to an arch.

For example, we all know that the glare off the water is sometimes worse than the direct sun, especially in the low/glancing light conditions of late afternoon- a bifacial panel takes advantage of this by receiving light on the bottom/back of the panel just as effectively as the front. Also, even in direct sun, the ambient light and the reflected light off the water still strike both sides of the panel, dramatically increasing its efficiency.


Please see the linked photos of the panels marketing materials to verify that it will meet your quality standards and fit your application.
If you would like more than two panels- thats great! Since we are already paying for shipping, adding panels is easy and I can give you totals for as many as needed.

https://drive.google.com/file/d/1Hjy...ew?usp=sharing
https://drive.google.com/file/d/1Xta...ew?usp=sharing
https://drive.google.com/file/d/1VPO...ew?usp=sharing
https://drive.google.com/file/d/15bC...ew?usp=sharing
https://drive.google.com/file/d/1-J3...ew?usp=sharing




I will receive the panels at a commercial loading dock in St. Petersburg Florida, inspect the packaging for damage at reception and bring your two panels to a previously agreed location for pickup.



I would prefer a deposit of half of the money up front and half upon exchange of the panels. Delivery is limited to a 1/2 hour drive time from St. Petersburg Florida- delivery at longer distances is mildly negotiable for a fee- but I am really not very interested in driving across the state.



PM me with any questions or interest.

Just to clarify, bifacial panels do not receive "light on the bottom/back of the panel just as effectively as the front." or at least they don't convert that light to electricity nearly as efficiently. In ideal conditions you'll get 30% of the power from the back as the front. And although it does seem like the reflection off the water is strong, the albedo of ocean water is only about .06, meaning only 6% of sunlight is reflected from the water. Meaning even if the back was 100% as effective as the front you'd only get 6% more power. So at the end of the day to you're getting 30% of 6%, or basically nothing additional.

[BenBowSirocco]

If the manufacturer of the panel claims it increases output of 30% from ambient light off the ground or roof, why wouldn't even just the intense ambient light of the tropics realize a similar result?



Also you may notice that I specifically mentioned the glancing light and late afternoon conditions- certainly on calm water at this time of day you would realize much more than the 6% reflectivity you would get during the direct light of the day. I know the glare burns my face and body much more in the afternoon- which is a tough time for most solar panels to realize their output- so anything that helps is a good thing in my book.



This particular panel manufacturer if you would have read the attached documents is only claiming a 20% increase. But just to clarify- that means for the same size and space requirements of a 405W panels you can achieve 485W. This is a significant amount and any increase in output for less space required seems like a sweet deal to me!



So thank you for your very pessimistic opinion posted onto my thread by the way. If you were not interested, you could just keep it to yourself troll.

[redneckrob]

Originally Posted by BenBowSirocco

If the manufacturer of the panel claims it increases output of 30% from ambient light off the ground or roof, why wouldn't even just the intense ambient light of the tropics realize a similar result?



Also you may notice that I specifically mentioned the glancing light and late afternoon conditions- certainly on calm water at this time of day you would realize much more than the 6% reflectivity you would get during the direct light of the day. I know the glare burns my face and body much more in the afternoon- which is a tough time for most solar panels to realize their output- so anything that helps is a good thing in my book.



This particular panel manufacturer if you would have read the attached documents is only claiming a 20% increase. But just to clarify- that means for the same size and space requirements of a 405W panels you can achieve 485W. This is a significant amount and any increase in output for less space required seems like a sweet deal to me!



So thank you for your very pessimistic opinion posted onto my thread by the way. If you were not interested, you could just keep it to yourself troll.

First, I own a company in the solar industry and work with this at a pretty massive scale, so I do know a bit about this topic and nothing I posted was an opinion. Secondly, most of us would appreciate if a person with expertise on something we clearly didn't have let us know we were mistaken before we spent money on it, especially if we were posting on a forum based on folks exchanging information. I'm sorry if you don't want to hear what I accurately conveyed and find simple facts "pessimistic", and certainly if you've got some ocean albedo numbers that differ from the generally accepted numbers in the literature or if you know something about the physics of bifacial cells I am unaware of I'd love to see the papers you're working off. But don't be an utter jerk and call me a troll simply for pointing out a physical reality that you apparently don't want to hear. What's wrong with you?

[BenBowSirocco]

Hi Rob,



Well lets start off by pointing out that this section "General Classifieds (No Boats)" is certainly on the forum, but not usually considered as an area of discussion, it is an area where people post things for sale.



So I was posting something for sale and you chose to write on my ad explaining that what I had for sale was pointless, then chose to claim your expert on the subject because you work in the industry, both of which make what I was selling seem a dismal prospect.

Do you make it a habit of posting on everyone's for sale ad? If I was selling a CQR, would you post that the CQR is terrible in comparison to a modern spade, that its setting and holding power is significantly lower than almost any modern anchor available and so its a bad idea to put one one your boat?



If I was selling a discontinued MFD, would you make sure to point out that it was discontinued and didnt qualify for updates and that it wouldnt be any good for anyone?



Or perhaps would you realize that everyone has to make their own choices based on their specific application for themselves and leave them alone about it??



I find your comments hold a very condescending tone- that is primarily why I called you a troll. You are not presenting information for discussion you are sourly stating numbers without much explanation or consideration of all variables within the application.

Your albedo numbers discussion based on the 6% light reflection of water does not include the deck of the boat, the sugar scoop, the stainless steel stern rails, or anything else someone might have under the panels that is specific to their particular installation. You do not know what they are doing with these panels and so your information while perhaps good to know is possibly mute.


Personally, even if I was to only realize 6% increase in output on the panels I will take the extra 24W and be happy about it. If they are to be mounted up there with their backs open to the ambient light, might as well get everything out of the real estate that I can.



I guess RedneckRob what I am asking is what are you trying to accomplish here, because so far I view your posts in MY FOR SALE AD are NOT HELPFUL.

[Wilyum]

Originally Posted by redneckrob

First, I own a company in the solar industry and work with this at a pretty massive scale, so I do know a bit about this topic and nothing I posted was an opinion. Secondly, most of us would appreciate if a person with expertise on something we clearly didn't have let us know we were mistaken before we spent money on it, especially if we were posting on a forum based on folks exchanging information. I'm sorry if you don't want to hear what I accurately conveyed and find simple facts "pessimistic", and certainly if you've got some ocean albedo numbers that differ from the generally accepted numbers in the literature or if you know something about the physics of bifacial cells I am unaware of I'd love to see the papers you're working off. But don't be an utter jerk and call me a troll simply for pointing out a physical reality that you apparently don't want to hear. What's wrong with you?

how dare you ruin his thread with professional expertise, facts and industry knowledge.

[BenBowSirocco]

Wilyum and RedneckRob,



Even if the panels only increase their output a small amount, why would this be a bad thing?? They take up the same amount of space and why not realize everything possible- it seems logical that taking light into the panel from both sides is a positive attribute here!

[BenBowSirocco]

It seems like a white deck would be pretty good. Polished stainless might be somewhat comparable to shiny aluminum foil- gives an idea. Polished arch would be good.
Just all depends on how they are installed for their particular application.



In my installation it will be probably about 60/40: 60 percent over the boat and 40 percent over the water. So depending on the predominant wind and the lay of the boat, you might realize a solid return off the deck.

[s/v Jedi]

Friends with these panels report 130% power output so the “expert” claiming 6% tops is clearly just a troll.

[sailingunity]

I purchased bi-facial panels from eBay a couple of years ago, and will be replacing them soon with regular panels. Main reason being the quality was quite low. One of the panels gets ~10% less output than the others. The build quality is a little cheap too. Output is less than rated (they are rated 220 + 20%), in reality I only see about 140 watts per panel in full sun. It's difficult to quantify if this is due to real world vs lab conditions, but I would have expected higher output than that.

I hadn't thought of what redneckrob mentioned, in my mind I imagined the same thing you did (that the light reflected was much stronger than it is), but it make sense that water is transparent and much of the light is absorbed further down. I would imagine that if you mounted these panels on a white roof the difference would be more noticeable.

It seems none of the major manufacturers are making bi-facial panels

[redneckrob]

Originally Posted by s/v Jedi

Friends with these panels report 130% power output so the “expert” claiming 6% tops is clearly just a troll.

If you were being sarcastic please disregard. If you were being serious, then I guess I'll just point out that some of us base our decisions on the results of heavily instrumented commercial facilities that show bifacial panels produce pretty much what the spec sheets call for with a specific albedo and others disregard that for what "friends with panels" report. To each their own I suppose, but again I have to wonder how anyone gets off calling someone who does this for a living pointing out the actual physics of this a troll?

To others who have reasonably pointed out that every little bit helps, that's a certainly a valid point of view. I would submit that that concern is best addressed by more efficient panels (efficiency in solar panels is the production per square unit in size) rather than bifacial panels. There are much more efficient panels out there that can product more than a bifacial of the same size even if you make the most optimistic of assumptions on the bifacial (although for those who truly believe that they receive "light on the bottom/back of the panel just as effectively as the front" we just really can't have an intelligent conversation on the matter since defies the physics of how they work). In the solar industry bifacial panels are only used in a few very specific use cases where there aren't size constraints and the area under the panels is unshaded and naturally high albedo like white paint (.5 to .7) or white concrete (.7 to .8) and even then they're really only in use now because they were exempted by a loophole from the solar panel tariffs which temporarily is making them cheaper than regular panels.

I'd love to see a video of an instrumented setup on a boat with bifacial panels to see what the actual effective albedo is. If you mount it high enough over a white deck (optimal is at least a meter) it will certainly do better than over water, but you also end up with shading issues that will pull it back down (shading on a solar panel has more than a pro-rata impact on production), so some real world documented results would for certainly be interesting. For those who actually care to dive into this, the so called "experts" at the Department of Energy have a modeling tool called SAM (system advisor model) that includes the ability to model bifacial pales that is free to download and play with, it can be found at https://sam.nrel.gov

[BenBowSirocco]

Originally Posted by sailingunity

It seems none of the major manufacturers are making bi-facial panels

This is not correct.
Even 3 years ago all the major producers made them and now the market is even larger. See dated article screenshot attached.

I might ask: Did you verify the manufacturer of the panel or the cells used in the panel you purchased were from a reputable supplier?

I'm sorry to hear the panels you bought from the FleaBay were of poor quality.






RedneckRob:

The panel manufacture claims just shy of 20% efficiency from the cells, a solid metric from the industry for the price point on its own. Making the back of the panel clear tempered glass and adding bus-bars to it, MIGHT add some output- for the last time- any additional output from the back of the panel is a positive in my book and something that makes sense IN MY INSTALLATION. I do not care to spend 3 times the money for a cutting edge cell producing 2-3% more efficiency.



I sure wish you would take the time to read my responses and be reasonable about this. No one is trying to make outrageous claims here: stop being a dick. You are clearly very knowledgeable, but you are so condescending about it that its repulsive.

[evm1024]

Originally Posted by sailingunity

It seems none of the major manufacturers are making bi-facial panels

Does LG count as Major?

https://www.solaris-shop.com/lg-neon...IaAqVcEALw_wcB

[evm1024]

...MIGHT add some output- for the last time- any additional output from the back of the panel is a positive in my book and something that makes sense IN MY INSTALLATION. I do not care to spend 3 times the money for a cutting edge cell producing 2-3% more efficiency.

$279 for 405 watt LG Bifacial does not appear to be 3 times. Sounds like time to update some knowledge.

[BenBowSirocco]

RedneckRob:

I tried to edit my post but it was to late. I apologize for name calling. Perhaps you do not see how condescending your posts are, but its frustrating.




This was completely unnecessary and shows you have not been actually reading what is being posted.

"(although for those who truly believe that they receive "light on the bottom/back of the panel just as effectively as the front" we just really can't have an intelligent conversation on the matter since defies the physics of how they work)"