bifacial panels any drawbacks?

[Zwy]

I can add onto the wings, welding those on would not be a problem and I can even weld extensions on the aluminum Iron Ridge.

After installing the 5 high array, I would not have a problem with one that high again. I found that array is easier to tilt up and down as the balance is better with 5 high. It uses 8 inch SCH40 poles compared to the 6 inch SCH80 and I think the 8 inch SCH40 is stronger. At full tilt I set this up for 5 feet of ground clearance but the next array can be lower, 3 or 4 feet as it will be in the yard without any traffic or snow removal needed around it.

I'm looking to make it 5 high and 2 or 3 wide depending on the panels. It is a single pole mount so twist will be a concern. 15 panels makes nice 7S and 8S strings so VOC isn't a problem. 10 panels makes either 10S or a pair of 5S. I can't use the 4 MPPT's in the LV6548's with either setup though and would have to use smaller series and probably parallel some strings.

 

[Brucey]

I have one more large MT Solar mount left to put up next year and have been looking at various panels. The mount will be 15 feet wide and can be just over 17 feet tall.

Using a bifacial panel that is a larger module than many would be advantageous. Something like this 530W Adani makes maximum usage of the mounting area of the mount. I could use 10 panels of just about any wattage so it might make more sense to spend a little more per watt and get a higher output panel. Mounts cost money too.

Yes the larger panels make sense with Mt mounts, personally I need panels I can move around myself. If that wasn't a concern something like the Canadian solar 680W jumbos may make more sense

 

[SunDave]

I went with 8" schedule 80 for robustness. More expensive, but in the overall picture, not terrible.

Since I have the solar itch like many on this forum, I would love to add an array of bi-facials and learn for myself. Maybe in a year or two, the tech will improve and make it an easy choice.

Most of the youtube videos about bifacial vs. non are a test on the ground with one of each panel. Or sponsored of course. I tend to trust my own data more.

 

[Zwy]

I went with 8" schedule 80 for robustness. More expensive, but in the overall picture, not terrible.

I can't see needing SCH80 with the 8 inch poles in my yard. I have enough buildings and wind break to break the wind. I do think there should be a brace from the bottom I beam to the pole base, not only to prevent the wiggle but to add strength to the complete structure. I've thought of a few ideas on how to do it but not a final design. Next year I'd like to get that figured out.

Since I have the solar itch like many on this forum, I would love to add an array of bi-facials and learn for myself. Maybe in a year or two, the tech will improve and make it an easy choice.

Most of the youtube videos about bifacial vs. non are a test on the ground with one of each panel. Or sponsored of course. I tend to trust my own data more.

With the panels tilted for winter I do wonder how much yield will be there. I do know once there is snow cover, cool temps and panels tilted to over 60° that I can get full rated wattage from the non bifacial panels for about 3 hours per day if the sun is shining. The albedo is just fantastic. I think a vertical mount with alternating panel orientation with bi facials would work very well with good snow cover.

 

[Zwy]

Yes the larger panels make sense with Mt mounts, personally I need panels I can move around myself. If that wasn't a concern something like the Canadian solar 680W jumbos may make more sense

Those actually would fit well 2 wide (94" x 2 = 188" with 180" beam mount length) and 4 high (51.3 x 4 = 205" with beams needing a short 6" extension) in landscape. VOC in 8S works too.

Thanks.

 

[Cmiller]

Bi-facial specs are for front-side only. Back side is additional benefits, but you need to remember that backside gains will add to the output amps, so if you max out your mppt amperage-wise going off specs, you might end up not gaining as much from the back side.

Weight of bifacial panels depends some on what the backsheet is actually made of. Some are glass and some are more of a plexiglass-ish material. We don't like the glass-backed ones because they are much heavier and also it seems like the back sheet is not tempered (could be wrong, but that's how it seems) because we have had quite a few back sheets shatter for us from being "tapped" by tools.

We use quite a bit of HT bi-facial panels and we have gotten to really like the HT 450 watt panels. The amperage comes out very nicely to be able to fully utilize 26-30A rated AIO mppt inputs. For instance, 12-14 of these in a 2P string setup make a nice amount for a Sol-Ark's mppt ranges.

Here is a picture that one of our customers posted on social media last winter. This is (36) 450w HT bi-facial panels. So 16.2kWp, ground mounted obviously.


So I guess that picture about sums up my opinion of bi-facial panels! Flat mount on a roof, you won't gain much honestly! But ground mounted or on a roof in a tilt-up config, they are worth it in my opinion!

 

[Kornbread]

Bi-facial specs are for front-side only. Back side is additional benefits, but you need to remember that backside gains will add to the output amps, so if you max out your mppt amperage-wise going off specs, you might end up not gaining as much from the back side.

Weight of bifacial panels depends some on what the backsheet is actually made of. Some are glass and some are more of a plexiglass-ish material. We don't like the glass-backed ones because they are much heavier and also it seems like the back sheet is not tempered (could be wrong, but that's how it seems) because we have had quite a few back sheets shatter for us from being "tapped" by tools.

We use quite a bit of HT bi-facial panels and we have gotten to really like the HT 450 watt panels. The amperage comes out very nicely to be able to fully utilize 26-30A rated AIO mppt inputs. For instance, 12-14 of these in a 2P string setup make a nice amount for a Sol-Ark's mppt ranges.

Here is a picture that one of our customers posted on social media last winter. This is (36) 450w HT bi-facial panels. So 16.2kWp, ground mounted obviously.
View attachment 259002

So I guess that picture about sums up my opinion of bi-facial panels! Flat mount on a roof, you won't gain much honestly! But ground mounted or on a roof in a tilt-up config, they are worth it in my opinion!

That really makes me want to get the bifacials, but Santan has the regular Vikram 375w panels on sale for $62.96 ... $.17/watt.

 

[Cmy]

Why not get the Vikram 375W bifacials for 22 cents per watt?

Focused on the 400W + panels and hadn't noticed them. Looked them up, hadn't seen before. Had preferred prefer the 420-450W panels for 36 (max 40) panel plan.

 

[Cmiller]

That really makes me want to get the bifacials, but Santan has the regular Vikram 375w panels on sale for $62.96 ... $.17/watt.

Yea, there are a lot of very cheap panels available anymore. My first 12 panels at home are the HT 450s on a ground mount. We get a semi load at a time at work, so we obviously get good pricing on these HTs as well.

I just got done adding some cheap used 300w Mage panels on our roof. 20 panels in a 10s 2p setup, E/W facing, run into one mppt on my Fronius.... mostly did it because they were extremely cheap, as we had removed them from a flat, rubber roof that was developing leaks after 7 or 8 years. (We didn't install originally.) The concrete blocks for the ballasted mounts were crumbling and causing leaks, so the company wanted them removed, since our quote for moving them 700+ feet to a steel roof was a pretty large number. (Would have needed to pull permits, add rapid shutdown, use completely new racking, etc., etc..... )

So personally, I do have non-bifacial panels too, where they are flat mounted on the roof and happened to be cheap. Lol. Sometimes cheap trumps most efficient and/or what I would prefer.

 

[Kornbread]

Mounts cost money too.

This.

Pricing new low cost panels. It seems the best bargain new panels are in the <400w range. The math'n is saying $.23-$.25/watt for bifacials delivered, and $.20/watt for regular mono delivered. Either way, all the ground mounts will need to be widened to support the extra width.

Now the question is what is it going to cost in steel, and my time, to widen the existing pole mounts vs a larger more costly panel that might fit the existing unmodified mount. Generally, I don't count my time, but steel cost me $.90 a pound.

The thought of snow covered panels still producing some power is nice.

It's never simple, easy, and cheap is it?

 

[ricardocello]

It's never simple, easy, and cheap is it?

Nope! Pick any two.

Nevermind, that’s for {fast, cheap, good}. same idea though

 

[Cmiller]

Here are some pics of how I did my ground mount. Simple pipe structure with uni-strut for the rails, etc. Sel-tapper screws through the strut into the panel frames, strut clamps to clamp to the top pipe (with screws to keep the clamps from sliding), I only put a piece of strut at every splice, but I'd recommend doubling up at least every other "splice", as I have a slight bit of a bow across the length top to bottom. I have a piece of strut horizontally at the top and bottom end of the uprights, to tie it all together. Then square tubing within square tubing for braces off each post. Posts are 5' deep by 24" round augered holes with 14 bags of sakrete in each hole.
P.S. Excuse the makeshift wiring looping a little anywhere..... 2 years later I actually have now finally cleaned up the wiring a tiny bit... lol

 

[Kornbread]

You guys really pi$$ me off. Everything was fine until getting involved in this thread. Now I'm sitting here counting the cash in the cookie jar and sending out emails for pallet prices and shipping quotes.

Hello group, my name is Korn E. Bread and I have a problem ...

 

[wpns]

I have a problem

Hi Korn, welcome, this is a safe space. Many grocery stores have coin counters to help with your problem.

 

[Justkeepitsimple]

Good to know, are you specifically talking about the Boviets or bifacials in general? I took a couple out of the stack when they first arrived and tested them out -seemed to be pretty stiff but at 7 feet long and heavy, bound to flex some. I should be mounting up all 32 panels in the next week or so.

Boviet Vega 450w/ 540w series. I have a couple temporarily mounted on a trailer at two points. When you look over the surface you can see some visual sag. They seem sturdy enough. The Pygmy goats decided to hop on them and tromp around on them a couple times [GOATS!!!]. No harm from it visually. The flex and sag is not grotesque but noticeable enough. They use cheap- version industry standard aluminum frame that smaller panels use (have some harbor freight 100w panels with same gauge aluminum frame). It’s the nature of the beast at almost 3.5’ x 7’ dimensions. Kind of presents some challenges mounting for maximum bifacial gain as you don’t necessarily want any bracing or mounting frame/ bracket-rey directly behind any of the rear facing solar cells.

 

[Justkeepitsimple]

Here’s this design decision guide for bifacial panels if it hasn’t been shared here already. Very helpful for understanding all the necessary variables and design decision choices for mounting bifacial Solar panels.

TLDR version: mount panels 3-4’ above most white surface as possible. Don’t cover rear facing cells with mounting bracket-rey whenever/ wherever possible.

 

[455dan]

Boviet Vega 450w/ 540w series. I have a couple temporarily mounted on a trailer at two points. When you look over the surface you can see some visual sag. They seem sturdy enough. The Pygmy goats decided to hop on them and tromp around on them a couple times [GOATS!!!]. No harm from it visually. The flex and sag is not grotesque but noticeable enough. They use cheap- version industry standard aluminum frame that smaller panels use (have some harbor freight 100w panels with same gauge aluminum frame). It’s the nature of the beast at almost 3.5’ x 7’ dimensions. Kind of presents some challenges mounting for maximum bifacial gain as you don’t necessarily want any bracing or mounting frame/ bracket-rey directly behind any of the rear facing solar cells.

Yeah I see what you mean. I think they over tightened the straps on the pallet at the factory, Luckily mine are all bowed out which should help them drain water.
Just got the panels on the mount this morning and need to align everything -but they are on the adjustable mount. YAY.

 

[455dan]

Boviet Vega 450w/ 540w series. I have a couple temporarily mounted on a trailer at two points. When you look over the surface you can see some visual sag. They seem sturdy enough. The Pygmy goats decided to hop on them and tromp around on them a couple times [GOATS!!!]. No harm from it visually. The flex and sag is not grotesque but noticeable enough. They use cheap- version industry standard aluminum frame that smaller panels use (have some harbor freight 100w panels with same gauge aluminum frame). It’s the nature of the beast at almost 3.5’ x 7’ dimensions. Kind of presents some challenges mounting for maximum bifacial gain as you don’t necessarily want any bracing or mounting frame/ bracket-rey directly behind any of the rear facing solar cells.

If you don't mind me asking what kind of power have they been providing per panel ?


ps. We had two Pygmy Goats for several years-(passed away due to old age), talk about characters!, they were very good at getting into the horses grain cans and yeah climbing up on things like the stacked hay bales as well. They liked cigarettes, beer, and McDonalds French fries as well.

Now to discuss with the wife, whether our one remaining horse will need to be fenced out of the array or will leave it alone....

 

[Kornbread]

If you don't mind me asking what kind of power have they been providing per panel ?


ps. We had two Pygmy Goats for several years-(passed away due to old age), talk about characters!, they were very good at getting into the horses grain cans and yeah climbing up on things like the stacked hay bales as well. They liked cigarettes, beer, and McDonalds French fries as well.

Now to discuss with the wife, whether our one remaining horse will need to be fenced out of the array or will leave it alone....

If you don't ground the panels on the array, you might not have an issue keeping the animals away.

 

[455dan]

If you don't ground the panels on the array, you might not have an issue keeping the animals away.

Pretty hard for an all steel direct mount with several feet of multiple posts in the ground not to be grounded.

I was thinking about the main ground at the house power box is one 8 ? foot copper rod, versus 4" x 9" x 11' C channel posts. Pretty Good chance the array is actually better grounded than the house is. First test of a panel before the sun went completely down and storm clouds rolling in.


A Massive 24 watts.

 

[Justkeepitsimple]

Yeah I see what you mean. I think they over tightened the straps on the pallet at the factory, Luckily mine are all bowed out which should help them drain water.
Just got the panels on the mount this morning and need to align everything -but they are on the adjustable mount. YAY.

Cool! I will be studying your ground mount construction assemblage when ready to permanently affix to the solar shed. I like the clearances you give the rear facing cells.

 

[Justkeepitsimple]

If you don't mind me asking what kind of power have they been providing per panel ?


ps. We had two Pygmy Goats for several years-(passed away due to old age), talk about characters!, they were very good at getting into the horses grain cans and yeah climbing up on things like the stacked hay bales as well. They liked cigarettes, beer, and McDonalds French fries as well.

Now to discuss with the wife, whether our one remaining horse will need to be fenced out of the array or will leave it alone....

Currently don’t know for sure power output per panel. Don’t have the data gathering capability’s for that ATM. I have two in series feeding a Tristar MPPT 60 Amp charge controller. 12 volt battery bank, controller can only feed a maximum of 700 watts/ hr output to battery bank (in 12V mode). It’s overpaneled within spec per controller documentation. Had a few overcast days recently still seems to feed the batteries good (our daytime usage rarely exceeds 250 watts/ hr). No shunt yet for monitoring exact power in-out but resting SOC on battery bank been not lower than 12.40’s V when I check battery voltage before sun comes up in early AM (we shut down inverter at bedtime 10pm-ish).

 

[Justkeepitsimple]

Goats goats goats!

 

[Kornbread]

Goats goats goats!

I loathe drying clothes outdoors on a clothesline. Putting on your pants only to find a wasp ... nope. Too many bitty stingy critters like to hide in em'.

 

[Mtnsonshine]

All of my bifacials are a bunch lighter in weight than similar sized normal panels.

What is the best company?