500W Panels - back mounted - 4 bolts only?

[eXodus]

I was wondering - my new 86 inch x 41 big panels have only 4 holes in the back for mounting.

While some smaller panels I have - had 6 or 8 holes

Are 4 bolt sufficient?
I can understand with front clamp mounts - yes 4 bolts are usually ok. But with the thin aluminum frame at the back - even with a substantial washer - I think that could be ripped out.

If you think that is to flimsy for high wind load - I just go ahead and drilled a couple more holes in the panels. Not really happy about it because warranty but hey - when they fly away, warranty doesn't cover it either.

 

[Brett V]

As long as the bolts you use are sufficient, it's not going anywhere. Most professionally installed residential systems using T clams have what works out to be 6 bolts holding 2 panels.

 

[eXodus]

As long as the bolts you use are sufficient, it's not going anywhere. Most professionally installed residential systems using T clams have what works out to be 6 bolts holding 2 panels.

true - but they are for clamping the front of the panel and are not going into the stamped out hole in the back.

 

[BryceFreeman]

Where are the panels installed? As long as the bolts are big enough and securely tightened, the wall/bracket where the panels locate is solid, the panels should be fine....

 

[yabert]

The 4 bolts (M8?) are evidently not the problem. The thin aluminum frame is 20x weaker than a M8 bolt.
Strange choice from the manufacturer as most put 8 mounting holes on the frame.
What panel is it?

I also second that where the panels will be installed is na important point to answer your question.

 

[eXodus]

Where are the panels installed? As long as the bolts are big enough and securely tightened, the wall/bracket where the panels locate is solid, the panels should be fine....

Florida, got hurricanes here. And they are going on a cargo trailer - so driving down the interstate twice a year from winter in Florida to Summer location in Atlantic Canada.

the thin aluminum frame is 20x weaker than a M8 bolt.
Strange choice from the manufacturer as most put 8 mounting holes on the frame.
What panel is it?

Correct the frame is my main concern. Not the bolts themselves the M8 Stainless steel bolts are plenty strong.

QCell Q.Peak Duo

I have Sunpower panels - which survived Hurricane Ian - those are mounted with 8 bolts each.

 

[BryceFreeman]

Surviving hurricane is impressive ? I read from online it's better to remove and put away the panels before hurricane to avoid damage. (sorry never experience a hurricane so know little about it)

 

[yabert]

I admit that is a real concern then.
There is no chance to take when driving those at interstate speed with possible cross wind, draft wind front truck, etc.
It could be envisageable to drill 4 others small holes in the frame for M6 screws.

 

[eXodus]

Surviving hurricane is impressive ? I read from online it's better to remove and put away the panels before hurricane to avoid damage. (sorry never experience a hurricane so know little about it)

You don't have enough notice to really do much aside of leaving. It is a very intense experience, one of the reasons - I'm going to spend my summers in Canada from now on. It is high stress and I had two of those monsters in the last 6 years (Irma and Ian) and getting tired of picking up and rebuilding.

We have few big solar installations which where in the direct path (130-150mph) wind and most of them didn't lose a single panel and power stayed on.

Hurricane Ian wiped out homes and power systems across Florida — so how did this small town escape mostly unscathed?

Babcock Ranch, with a population of around 5,000 people, is located on Florida’s southwestern coast, where Hurricane Ian hit in September.

www.thecooldown.com

Solar-powered Fla. town of Babcock Ranch survived Hurricane Ian - UPI.com

Babcock Ranch, Fla., the first town in the United States to run solely on solar power, didn't lose electricity or Internet when Hurricane Ian blew through.

www.upi.com

I admit that is a real concern then.
There is no chance to take when driving those at interstate speed with possible cross wind, draft wind front truck, etc.
It could be envisageable to drill 4 others small holes in the frame for M6 screws.

I'm thinking that way too. Don't want to endanger others. Just wondered why the manufacturer only put in only 4.....

Guess I'm going to drill a bunch of holes in my new panels Probably should test them first.

 

[SeaGal]

I was wondering - my new 86 inch x 41 big panels have only 4 holes in the back for mounting.
While some smaller panels I have - had 6 or 8 holes
Are 4 bolt sufficient?

The info re mounting options is included in the installation manual, including the design and test load for push/pull when using just the 4 mounting points - see page 10, mounting option FB1.

https://media.q-cells.com/v/eyEEJh2F/

Obviously you'll need to calculate the expected loads for your specific installation location under hurricane conditions

I like to over-engineer everything, so think I'd secure the panels in more locations if it were me.

 

[eXodus]

mounting option FB1.

Thanks for that manual. According to that manual the 4 rear mounts should provide the same load capacity as a front clamp CL1a?
Those German Engineers must have high confidence in their frames

Our base rating here is for 110 mph, which like 3700PA. That is too close for my comfort level to 4000PA pull. Since experienced already more here, multiple times.

When I double the fasteners, it should be strong enough to survive any storm - which doesn't take the structure itself away.

 

[Lt.Dan]

I think it shouldn't be very hard to drill 4x more holes in the frames

 

[SeaGal]

Our base rating here is for 110 mph, which like 3700PA. That is too close for my comfort level to 4000PA pull.

Agree esp. as the design pull is only 2660Pa - the 4000Pa figure was a test load.

I think it shouldn't be very hard to drill 4x more holes in the frames

just take care you don't slip or go too deep.

 

[SeaGal]

or enlarge and repurpose the grounding holes?

 

[eXodus]

I think it shouldn't be very hard to drill 4x more holes in the frames

just take care you don't slip or go too deep.

it is not difficult to drill those holes. I've drilled panels before, I was just hesitant because these are new with warranty. At least now I would have paper trail with the manual and load calculations - that additional holes where required - in case something would ever come up with warranty claim denied or so.

Just put a piece of high density wood in the panel frame underneath the section you are drilling. So in case you punch through, it doesn't break the glass, or the scrapes the plastic backing.

New drill-bits go through the aluminum frame like butter.

enlarge and repurpose the grounding holes?

that is actually a interesting idea - the grounding holes are tiny, and the trailer I'm putting it on is all metal - so I got lots of grounding and I would not need them. Have to check out if they are in the right locations. Otherwise I'm likely just putting in another hole close to the existing hole - and use a wide bracket to attached which gets 4 screws/bolts into the trailers.

https://a.co/d/dlxP3Lr

I've used those on my RV before and they are massive - 2 bolts to the panel and 4 to the vehicle.

 

[yabert]

Use the tiny grounding holes if they are well placed is make sense.
Considering a tiny graded M5 bolt can hold over 1000 lbs, 4 of them in addition of the 4 M8 bolt should be way enough.

 

[BryceFreeman]

You don't have enough notice to really do much aside of leaving. It is a very intense experience, one of the reasons - I'm going to spend my summers in Canada from now on. It is high stress and I had two of those monsters in the last 6 years (Irma and Ian) and getting tired of picking up and rebuilding.

We have few big solar installations which where in the direct path (130-150mph) wind and most of them didn't lose a single panel and power stayed on.

Yes I understand how annoying picking up and rebuilding are. Now I know the reason why you said 4 bolts are "only" ? looks like drilling more holes in the frame is a must do.

 

[Blown284]

What bolts/system are you going to use to bolt the 550w down?

 

[Bluedog225]

Or put a long, thin strip of backing material, running from bolt hole to bolt hole, to serve as a long washer

 

[eXodus]

What bolts/system are you going to use to bolt the 550w down?

Just got M8-1.25 x 20mm Stainless Hex Bolts Going to use 8 of them.

Each of those have enough yield strength that it should not go anywhere.

Or put a long, thin strip of backing material, running from bolt hole to bolt hole, to serve as a long washer

that is an interesting idea. But then I have to align a bunch of things- washer plate, panel, and bracket + washer + locking washer + nut.

Got the panel currently on my floor and looking at the frame - and the flange for the rear mount is pretty thick. That's why they probably can get away with specifying only 4x M8s

8x M8 screws with large washers should be OK. It is double what the manufacturer requires.