Ability of Sanyo's to handle snow load

dale

My installer usually uses Sharp 170's since he's had no problem with the panels in the past. He said he's heard they have a very good reputation for respondinng when problems occur.

Roof space was a concern and I'd expressed interest in adding more panels at a later time. They approved upping my rebate to 3.6kw. A sale on Sanyo 186's make switching to these possible. It adds a couple of months to my payoff period, but the output would significanly more.

Anyone have any experience with these panels? Computer CPU's are usually cut from the same die and then rated based on their acutal output. Is this how they do panels? The positive is that they take less space and their efficiency is higher. I also remember reading, but haven't been able to find it since, that they have a better angle (or window) of response when the panels are not 'optimally' positioned.

On the negative side, they have a 20 yr warranty with plenty of small print. Part of this is that they do not cover 'heavy snow' damage. The spec sheet lists a 39 PSF static snow load. My roof is going to have a '6' pitch, which works out to be around 27 degrees. On occassion, we've gotten 26" of snow in a 24 hour period. I'm wondering if this will present a problem in light of the roof incline, smooth panel surface, etc.

BTW, the NJ BPU has said they are considering an extension of the residential rebate program. If it happens, it will probably only be for a short period. http://www.njcleanenergy.com/misc/renewable-energy/core-queues

Thanks in advance for your help.

mike95490

Re: Ability of Sanyo's to handle snow load

What area are you in ? Someone way up north has some steeply inclined panels, and says they heat up, and melt the snow off quite readily. At normal roof angles, at nighttime, I don't know. If the surface area is smaller, I would think they could be sturdier. How does their load compare to the other panels you were looking at?

BB.

Re: Ability of Sanyo's to handle snow load

You might ask Solar Guppy about his current experience (if any) with the Sanyo HIT ASI type panels...

From this 3 year old thread, he has been recommending to let others experiment with these panels first to see how well they work over time.

-Bill

westbranch

Re: Ability of Sanyo's to handle snow load

re roof pitch:

a 6:12 pitch is fairly 'flat' wrt snow coming off on its own, even on a metal roof, though it will let go, usually at 2 AM, just to wake you up.....an 8:12 metal roof will shed the snow much more readily.

If you have a duroid roof it will not shed... so the snow on the panels has no where to go once the snow depth is greater than the height of the PV mount... it has to melt off.

Cheers
Eric

Solar Guppy

Re: Ability of Sanyo's to handle snow load

I have read about panels being destroyed by ice damming under panels, thats the real concern with low pitch roofs and very real. If your low pitch, you need to stand off the roof by LARGE amounts so ice damange won't happen from the underside of the solar panel.

As far as Sanyo's, My opinion hasn't changed, for the small increase in efficency your taking the risk of the hybird Asi/Si mix without any independant long term data.

Sanyo was dropped by some dealers last year when they came out and said areas with more then 100F and humidity of more than 85% would void the warranty and after a huge stink reworded to something like average temp/humidity. My Si panels run 75C for more than 6 months a year here in Florida for an Idea of how hot panels get on a roof. Even with the wording change, its begs the question what caused sanyo to have reduced tempature/humidty needs in the first place, Si panels have no such limits

Nothing beats the cost/payback of Si seconds ( like what is sold by www.sunelec.com ) and then Multi Si panels .. I don't see any value in the marketed claims of the HIT technology. The investment being in the 10's of thousands is just way to much money to be using anything by Multi or Mono Si

icarus

Re: Ability of Sanyo's to handle snow load

It depends on where you live, what your snow is like, and if you can get up to remove it. 39 psf would be a huge amount in many places, but less so in the Cascades or the Sierras. If you have a way to clear it, if you get big dumps regularly then I wouldn't worry about it. On the other hand if you can't clear it, and you live in a climate of 6 months of snow like we do, then you have a problem. Solar guppy makes a good point about ice damming however. Also consider the possibility of snow sliding ABOVE the panels damaging them. The concentration of snow coming off a standing seam metal room is huge, as Westbranch suggests.

Good luck,

Icarus

PS. We had had 8" of fresh snow yesterday. The first real day above freezing was three days ago! Snow forecasted for another week at least.

System2

Re: Ability of Sanyo's to handle snow load

To be honest, if you live in a snow area, having your panels flat like that will render them basically useless in the winter, unless you plan on repeatedly climbing up on the roof all winter long to keep cleaning them off.
If you have no choice and can't keep climbing up there during and after each snowfall, then it might be better to consider taking them down for the winter, as under all that snow they won't be producing power anyway and if taken down, you won't have to worry about the snow load breaking them.
Mine here in Nova Scotia are almost vertical for the winter. The snow slides right off, the sun is low on the horizon through the winter and the panels receive light both directly from the sun AND reflected off the snow covered ground. Couldn't ask for better.
Cheers
Wayne

dale

Re: Ability of Sanyo's to handle snow load

Thanks to everyone who replied. The racks were installed today and the panels arrived. The panels will be put up on Wednesday or Thursday.

I wish I'd read all of the comments before saying telling him to order the Sanyo's. I hate to be breaking new ground, but it looks like I'll be the first to be able to give you first hand information about them.

I'm in northern NJ. We can get heavy snows, but it isn't the norm. Normally an inch or two will stay on the north side of the roof. I'll have snow on the ground from late December through March, but the roofs usually lose it fairly quickly. That might change after I add more insulation in my attic.

I've heard that the panels shed snow quickly, but that might be a snow job. :roll:

Solar Guppy, the site looked good, but I wasn't sure what Si panels are. Is this a technology or company? Are they seconds due to cosmetic issues or performance? What kind of warranty do they have?

Thanks again for your helpful comments. BTW, the NJ rebate/srec program seems to be in total confusion. It's hard to say if they are going to continue with the srecs. To keep the payback under seven years requires both. My advice for people in NJ, who don't have money to burn, is to wait for the dust to settle before jumping in.

BB.

Re: Ability of Sanyo's to handle snow load

"Si" panels are the standard "Silicon" poly or mono crystalline solar panels that are used by the vast majority of us today...

There are thin-film type panels that are ASI (Arsenic and Silicon? edit: this is wrong--it is amorphous silicon which does not use arsenic) hybrids that are good for flexible installations (rock resistant like UniSolar and for portable applications) and one vendor Sanyo for Grid Tie applications...

ASI / Thin Film have also been heavily used/sold for small installations (third world and yard lights) because they can be cheaper to make--but there have been various issues with both the vendors and the ASI technology and one should avoid them unless there are specific needs that only these panels can meet (all of this is my reading of information out there today--I am not the expert in this field).

-Bill

Brock

Re: Ability of Sanyo's to handle snow load

Jumping in late, but we had 88 inches this year and the snow never sat on them for more then a day. They are tilted about 60* straight south, so the snow slides off them pretty quickly. They are raised about 9 inches off the roof on the low side and a good 24 inches at the top, they are mounted up near the peak so not much snow slides down under them.

It is funny now that it is warmer the only snow left of the roof is hiding in the shade under the panels.

westbranch

Re: Ability of Sanyo's to handle snow load

Brock, do you know the pitch rating of your roof? 6:12, 8:12. 10:12 or steeper?

Are the panels parallel to the roof surface or raised above the roof plane ?

Cheers
Eric

Brock

Re: Ability of Sanyo's to handle snow load

They are on my father in laws garage right now (we sold our last house and building a new one). The garage is south facing and 4 in 12 pitch, barn style, steeper on the sides, 12 in 12 and then the 4 in 12 at the top section. The bottom of the panels are 9 inches above the roof and the top is about 24 inches.

Mangas

Re: Ability of Sanyo's to handle snow load

My Sharp's shed snow fine, went through a bad hailstorm as well as three very hot summers (peak over 105 degrees). No ill effects observed. They look pretty robust to me.

Occasionally, I've used a soft broom to clear snow and wonder if that is the smart thing to do?

Solar Guppy

Re: Ability of Sanyo's to handle snow load

Your tag says your panels are 40 Sharp's , is that in error?

mike95490

Re: Ability of Sanyo's to handle snow load

What sort of a lip or ridge, do they have at the bottom edge ?

Is their glass flat, or textured ?

All will affect how well the snow will slide off.

Mangas

Re: Ability of Sanyo's to handle snow load

Gup, yes, you're right I have the Sharps'. Sorry about the errant post. I'm getting old and very slow.

System2

Re: Ability of Sanyo's to handle snow load

BB. wrote: »

There are thin-film type panels that are ASI (Arsenic and Silicon?) hybrids that are good for flexible installations (rock resistant like UniSolar and for portable applications) and one vendor Sanyo for Grid Tie applications...
-Bill

Would "aSi" likely refer amorphous silicon types of cells?

BB.

Re: Ability of Sanyo's to handle snow load

cwhitlat wrote: »

Would "aSi" likely refer amorphous silicon types of cells?

Cwhitlat,

I think you are correct and I am wrong... They are thin-film amorphous + crystalline silicon panels.

Thank you for correcting my error. I don't know where I picked that up (other than As and Si being the chemical symbols of same).

-Bill

Dave Angelini

Re: Ability of Sanyo's to handle snow load

Ba da boom! The Sanyo panels I have specified at 2 homes in snow country have been fine for 2 years now. Sad that the OP does not have the Sanyo panels as he hould have noticed how well they do in hot weather. I am still fairly amazed that the 1800 watt arrays are getting 1600 watts out above 95F after 2 years. It sure does not show in their temp. comp.

The above panels are in series logging about 140v in the winter morning cold. I never worried about being that close on the XWCC. Through the grapevine I heard that 140V will easily meet spec on a new revision. Also Sanyo is building a new panel with only 36 cells so it will be easier for the conservatives out there to use Sanyo.

Anyone else have any other panel reccomendations that maximize wattage per square foot? Any that people can buy????