Home Rooftop Solar Power System Update - Shattered Panel!  - Page 1
Forum section: electronics / general

author: EEVblog
author_rank: Unknown
timestamp: December 06, 2015, 03:57:06 am
content: One of Dave's LG Mono-X solar panels has mysteriously shattered!Daily solar output data:http://pvoutput.org/list.jsp?userid=22501Sorry for the audio and video quality, this was shot on my phone.

author: djQUAN
author_rank: Frequent Contributor
timestamp: December 06, 2015, 04:16:12 am
content: Stray bullet perhaps? or someone with a slingshot and BB/marble?PV modules are made with tempered glass which are pretty strong against wind and hail but shatter into a million pieces when cracked. I think you could just get a spare and use the broken one until output drops significantly to maximize your investment then replace it immediately.

author: Radio Tech
author_rank: Frequent Contributor
timestamp: December 06, 2015, 04:16:59 am
content: Solar roadwayAlmost looks like a baseball maybe? Interesting.

author: DrGeoff
author_rank: Frequent Contributor
timestamp: December 06, 2015, 04:22:02 am
content: Looks like a misplaced cricket ball or golf ball landed on your roof.Remember LG = Lucky if it Goes

author: ornea
author_rank: Unknown
timestamp: December 06, 2015, 04:23:12 am
content: Anything get caught in the gutter?

author: EEVblog
author_rank: Unknown
timestamp: December 06, 2015, 04:23:16 am
content: Quote from: djQUAN on December 06, 2015, 04:16:12 amNo way a marble had enough energy to shatter that.We don't have a gun culture in Australia, and so hardly anyone has one. So the odds of that are borderline zero.

author: chickenHeadKnob
author_rank: Super Contributor
timestamp: December 06, 2015, 04:24:55 am
content: I live about 400 meters away from the ocean where mud flats get exposed at low tide. Gulls and ravens pick up mollusks and crabs and such during low tide. The gulls fly to about 20 or 30 meters altitude and drop their goodies on rocks right at the beach, to crack them open. The ravens on the other hand bring their stuff to my house and hammer away like a construction crew on my roof. They only do this during the months of late march through to about early july and only in the mornings. This might be because of the pacific ocean mixed tides are low in the mornings at this time of year and they have young in the nests in nearby trees they need to feed. They only come to my roof!, its infuriating, and I don't know what's special about my house. My shingles are holding up, but I suspect solar panels wouldn't last. Those phu**kers like shiny things and would make use of hard edges as anvils for sure.

author: djQUAN
author_rank: Frequent Contributor
timestamp: December 06, 2015, 04:26:26 am
content: I wouldn't think a baseball could break the glass since it is tempered and the ball is kind of soft. Although it could happen with sufficient force but from above? Not really sure.What could do that kind of damage to a tempered glass panel is something hard like a BB, bullet, marble or rock. With a small, very hard pointed object, it doesn't really take a lot of force to break tempered glass.A small bit of cracked ceramic from a spark plug thrown by hand could easily shatter car windows.

author: Lightages
author_rank: Unknown
timestamp: December 06, 2015, 04:27:20 am
content: I think the answer came from the sound half way through the video. An airplane.... Perhaps something fell from an airplane, a bolt, nut, piece of ice....

author: Psi
author_rank: Super Contributor
timestamp: December 06, 2015, 04:56:06 am
content: If its still working maybe just add an extra panel instead of replacing it.It's going to fail eventually as water gets down the cracks but might as well use the power while its working.

author: ornea
author_rank: Unknown
timestamp: December 06, 2015, 05:02:26 am
content: As a string of panels are in series, the impedance of a single panel can drastically effect the overall performance of the string. If it fails sorted not so bad I think but if it fails with increasing resistance, not so good.Therefore it is best to replace to maintain peak performance.

author: djQUAN
author_rank: Frequent Contributor
timestamp: December 06, 2015, 05:06:27 am
content: PV modules have bypass diodes so when it fails or output drops, the array still works but the total output drops by one module.

author: Klomderper
author_rank: Newbie
timestamp: December 06, 2015, 05:09:39 am
content: I would add CCTV cameras to monitor the panels and surrounding areas.

author: NoItAint
author_rank: Contributor
timestamp: December 06, 2015, 05:23:24 am
content: Maybe a Ninja rock from a stupid kid sling shot?https://en.wikipedia.org/wiki/Ninja_rocks

author: rs20
author_rank: Super Contributor
timestamp: December 06, 2015, 05:42:10 am
content: Quote from: ornea on December 06, 2015, 05:02:26 amRight, but wait until performance drops first, right? We don't need to speculate here, he can measure performance and see if/when it starts to deteriorate (which I think it obviously willat some point). If I was him, and I didn't get it replaced on warranty, I'd wait until it starts to actually fail, get the most out of my investment.

author: Cyberdragon
author_rank: Super Contributor
timestamp: December 06, 2015, 05:48:42 am
content: If someone wanted to bust his panels they probably would have busted them all. It was probably an accident or birds.

author: Brumby
author_rank: Unknown
timestamp: December 06, 2015, 05:50:20 am
content: Disclaimer: I'm no expert.My first thought was a cricket ball. I also wondered about a golf ball - but I reckon it would have to have been a pretty full-on shot to have enough energy to do that damage. Also, a golf ball might disappear down a downpipe.Rocks - yes, but since most rocks aren't of rolling shape, you would expect the culprit to be laying around, unless is skipped off somewhere.Unless someone has experienced this before and can tell us what has (likely) happened, it will remain a mystery.I suspect the supplier could give you an answer as it would seem they would be most likely to have come across it before.

author: Tomorokoshi
author_rank: Super Contributor
timestamp: December 06, 2015, 05:57:51 am
content: Actually, I think the pattern is very pretty. Kind of a galactic formation or supernova motif.

author: SeanB
author_rank: Super Contributor
timestamp: December 06, 2015, 06:00:37 am
content: You can actually repair that panel, using stuff available in Australia and there is an online video about doing so.If he can do it, and you use his instructions ( really detailed and pretty simple to follow as well) you should be able to get that panel waterproof again before the rain damages it for a pretty low cost.

author: Slothie
author_rank: Regular Contributor
timestamp: December 06, 2015, 06:18:55 am
content: If you're under a fkight path I'd say a chunk of ice from a plane. If it was a rock, ball etc it would have been in the gutter or on your path. Ice would just melt away.

author: Whales
author_rank: Super Contributor
timestamp: December 06, 2015, 06:30:30 am
content: Tip if this video sounds strange to you: disable one of your speakers. Somehow the L and R channels have ended up out of phase.

author: Chris Jones
author_rank: Regular Contributor
timestamp: December 06, 2015, 06:35:44 am
content: It might have been worth pointing out to viewers that it's probably not a great idea to go poking the broken parts with one's fingers, if the string of panels is all still connected together. Whilst the safety risks of solar electricity are somewhat over-emphasised in Australia when compared to that nice friendly coal electricity, the string voltage could probably still give you a shock, and in many cases the inverter doesn't float the string with respect to the mains so I wouldn't even go poking the broken panel at night.

author: Phoenix
author_rank: Frequent Contributor
timestamp: December 06, 2015, 06:42:21 am
content: Out of curiosity does your inverter report the array insulation resistance? I wonder how much this changes with a cracked panel and water ingress...

author: Wytnucls
author_rank: Super Contributor
timestamp: December 06, 2015, 06:51:05 am
content: Meteorite damage is not uncommon. Certainly more likely than ice or metal bits falling off airplanes. Meteorites are sought after, so any chunk that survived the impact might be worth looking for.http://www.redding.com/news/unidentified-object-from-sky-destroys-car-in

author: TheSteve
author_rank: Unknown
timestamp: December 06, 2015, 07:05:59 am
content: What games do your neighbors usually play in their backyard?

author: Halcyon
author_rank: Unknown
timestamp: December 06, 2015, 08:15:41 am
content: If there is no signs of a ball or other obvious object in your yard which could have caused the damage, another idea might be someone was actually on your roof (trying to break in) and stepped on it. Break-ins via roof tiles aren't totally unheard of. As Klomderper has already suggested, CCTV isn't a bad idea. You should be able to pick up some second hand professional POE cameras for a reasonable price.I'm not suggesting you stick one on your roof, but it's quite easy to jump up on Colourbond fences to gain access to the roof.

author: EEVblog
author_rank: Unknown
timestamp: December 06, 2015, 08:26:37 am
content: Quote from: Halcyon on December 06, 2015, 08:15:41 amAbsolutely no way that damage is caused by someone stepping on it.

author: con-f-use
author_rank: Unknown
timestamp: December 06, 2015, 08:50:19 am
content: Doesn't your home insurance cover weather damage?

author: PinheadBE
author_rank: Regular Contributor
timestamp: December 06, 2015, 09:10:05 am
content: Did you have bad weather recently? If so, it could be a shark....https://youtu.be/6S5Jus9VLKANo, seriously: Look how the panel seems to be bent inwards. This is not a golf ball or whatever.Besides, the impact looks very round shaped, so the angle should be near 90°, meaning free fall.My best guest would be a tiny meteor, or a metal piece fallen from an airplane.Just my 2c

author: Psi
author_rank: Super Contributor
timestamp: December 06, 2015, 09:14:26 am
content: Most likely is just a ball of some sort and the person came onto the property and retrieved their ball after it rolled off the roof.Meteorites come in very hot, you always find things melted/charred nearbySomething falling from a plane is possible, but pretty unlikely.The impact looks like it involved quite a large amount of force. So i'm thinking a hard ball (cricket, golf), that was hit almost vertical from the property on either side, or from the street.A potato gun is also a possibility but i would have expected potato fragments on the roof. I suppose if it happened long ago it might have decomposed and been washed away by rain.

author: jitter
author_rank: Frequent Contributor
timestamp: December 06, 2015, 09:22:09 am
content: IMHO, it wasn't caused by something coming from below, like a golf ball. I can't imagine that it could have acquired enough energy to do damage like that, especially if it were coming in under less than a perfect straight angle. Angles shallower than 90 degrees probably would have caused it to skip off.IMO, hail seems the most likely cause. If you're hit by a freak hail storm, there's hail stones coming down the size of tennis balls and bigger.These get quite a lot of energy because they get the time to accelerate when they fall to earth and all of that energy is released during impact.The impact site on your panel looks peculiar. The "crater" seems to have a hill with the top right in the centre. I wondered why that had happened and came up with this theory: a big hail stone hits the panel with tremendous force and since it's round the point of impact is tiny, at first. This pins down the glass at that point against the solar cells. As the impact progresses, the ice crushes and the contact area becomes bigger, so the force on the glass around the centre doesn't pin it down anymore and it can be hurled away. A fraction later, the energy released melts the ice and suddenly, the hail stone cannot break the glass anymore, hence the nice round shape of the impact. When the impact is almost over, the pressure on the centre releases and the energy dissipates, having not enough force to expell the glass, leaving this "hill".It came as a surprise to you, so the impact might have happened while you were away. But it might have happened while you were home. Among the thousands of hail stones hitting the panels, there may only have been one with enough energy to shatter the glass.Youtube is riddled with freak hail storm clips from all around the world. The one that is printed in my memory is from somewhere in Germany where a freak hail storm destroys tough ceramic roof tiles that might have been on that roof for many decades. I'll try to find it and post a link.Edit: not the one I was looking for but even better:I was wondering if hail storms ever hit Sydney after I had written this and did a quick search...oh yeah, they do indeed...

author: crispy_tofu
author_rank: Super Contributor
timestamp: December 06, 2015, 09:54:34 am
content: Quote from: con-f-use on December 06, 2015, 08:50:19 amBut was it caused by the weather?

author: Artlav
author_rank: Frequent Contributor
timestamp: December 06, 2015, 10:02:11 am
content: Quote from: Psi on December 06, 2015, 09:14:26 amActually, no.If a meteorite was hot enough to char anything by the time it hit the ground, this would have made international news to the effect of "a meteor impact wiped out a neighborhood in Sydney".Small (under a few tonnes) meteorites are already falling at terminal velocity as high as airplane height, and by the time they hit the ground they are long since metal-cold.The famous Chelyabinsk meteor's main chunk was going at terminal velocity near the ground, and it was large enough to poke a big hole in the ice of the lake:And that's with a 500 kiloton worth of a meteor.

author: G7PSK
author_rank: Super Contributor
timestamp: December 06, 2015, 10:08:46 am
content: What ever hit that panel was fairly small only a mm or two in diameter. Check for a small hole in the middle most of the damage is due to shock waves.

author: kaz911
author_rank: Super Contributor
timestamp: December 06, 2015, 10:13:55 am
content: My bet is a Delivery guy - with a test power supply from Siglent.http://www.birminghammail.co.uk/news/midlands-news/sorry-your-parcel-roof-yodel-10485972... it does happen ...so are you missing any parcels ?

author: FireFlower
author_rank: Regular Contributor
timestamp: December 06, 2015, 10:35:54 am
content: My theory:Why you didn't find proof would mean the turtle or similar survived impact and bird took its prey to drop it again elsewhere.

author: RodG
author_rank: Newbie
timestamp: December 06, 2015, 11:21:29 am
content: Had a (stray?) home-made concrete projectile break my tile a few years ago. I assume it's from a air-cannon some kids had made up. Look around and see if you can find something similar.

author: PE1RKI
author_rank: Regular Contributor
timestamp: December 06, 2015, 12:03:14 pm
content: maybe the thing that fell on it is still in your garden or left traces in the sand when it fell of the roof.

author: mikeselectricstuff
author_rank: Super Contributor
timestamp: December 06, 2015, 12:15:49 pm
content: As it's toughened glass, I wonder if it could have been a latent manufacturing defect that popped due to normal thermal cycling.

author: ornea
author_rank: Unknown
timestamp: December 06, 2015, 12:19:40 pm
content: Still curious if there is any debris in the gutter.Perhaps Dave could get the panel under the scope and look for fragments of rock, balls etc.Unless it has rained recently there should be something detectable unless it was ice.

author: zoltan
author_rank: Contributor
timestamp: December 06, 2015, 12:25:32 pm
content: Maybe hail with metal core? You have a bent nail next to the panel. (@3:37).Strong wind can easily pick up something like that, and later in the clouds it act as a solid core to form deadly hail.Could you take that nail under microscope? One end should have some visible damage if it is a culprit

author: Ian.M
author_rank: Super Contributor
timestamp: December 06, 2015, 12:27:32 pm
content: If Dave's place is under a flightpath,https://en.wikipedia.org/wiki/Blue_ice_(precipitation)

author: EEVblog
author_rank: Unknown
timestamp: December 06, 2015, 12:30:20 pm
content: Quote from: Ian.M on December 06, 2015, 12:27:32 pmLess than 500m offset from one.

author: PE1RKI
author_rank: Regular Contributor
timestamp: December 06, 2015, 12:33:08 pm
content: in the video you can see a round dent in the center. something round and heavy fell with on it at high speed.a nail or golf ball dont have the mass to do this kind of damage.i say it was a big chunk of ice or a baseball or a meteorite. baseball might have been retrieved, ice melts and a meteorite can blend into the garden.if something fell out of a plane, it must still be around the house. the glass broke in such a way that i dont beleive it can bounce far away.more like a "thud" sound and then rolled of the roof.

author: Rasz
author_rank: Super Contributor
timestamp: December 06, 2015, 12:55:32 pm
content: looks like golf ballhttps://www.solarpaneltalk.com/forum/solar-panels-for-home/solar-panels-for-your-home/19787-golf-ball-damage-protectionthat Epoxy resin looks interesting, I wouldnt necessary import overpriced stuff from US, but investigating locally obtainable UV resistant substitute could be a viable fix on the cheap. It will fix refractions caused by cracks and protect from moisture.

author: zoltan
author_rank: Contributor
timestamp: December 06, 2015, 12:56:06 pm
content: Quote from: mikeselectricstuff on December 06, 2015, 12:15:49 pmThis summer I had a broken rear windshield on my car. It was in "one piece" until I noticed the rear window is strange "milky" looking and stopped the car. Then the kinetic energy just shattered it to pieces. Nothing was found inside, and the glass had no impact signs.Dave's panel has a clear impact point, while it could be manufacturing defect, it has to be combined with impact. And there is a large nail under the next panel, if frozen inside hail ball it could pierce the glass on impact.

author: bitwelder
author_rank: Super Contributor
timestamp: December 06, 2015, 12:57:13 pm
content: Also, no clue *when* it might have happened?As I understand, no drop in produced power and nobody heard the noise of the shattered glass (and/or the impact with the unknown object), so last datapoint in time is when Dave has previously inspected the panels?

author: Brumby
author_rank: Unknown
timestamp: December 06, 2015, 01:11:39 pm
content: Sometimes I like diagrams ... and I was curious about the impact damage, so I looked through the video a couple of times to try and make out what broke where.This is my best guess... (BTW when I say 'panel' I mean the protective glass panel, nothing else.)The centre white zone I am calling the crush zone and I suspect it might be rounded to match the shape of the object at the point it struck the panel. I've used a cricket ball as a suggestion (you'll find more of these than baseballs around Australia), but the object needn't be spherical. I would not exclude a freakishly large piece of hail.As the object first hit the glass, the point of contact would have failed, causing the panel wide cracking to begin. As it progressed, more surface area of the object came into direct contact with the glass which caused high density cracking, resulting in the white centre and the crater shape.As the object penetrated further, the area of glass around the object would have been trying to bend down. As the object transferred more of its energy to the glass, the pressure increased to the point where a shear failure occurred (if I got that term wrong, I apologise) causing the white ring out from the crush zone - which I think has a step as I have put in my diagram. I suspect the location of the shear failure ring will be a function of a leverage component in the bending down action mentioned above.All the other cracking over the panel just appears to be the typical result of tempered glass failure.Also, upon mulling it over, I don't believe something the size of a golf ball would create the damage shown. Yes, a golf ball might shatter the panel, but if so, I think the 'fingerprint' would be much smaller. Likewise, I don't believe it was a sharp-pointed object. Yes, a sharp pointed object could find a point of weakness that shatters the panel, but I can't see how it would leave that 'crush zone'.If the 'crush zone' is rounded and you can get some sort of measurement on the curvature, you might be able to work out a rough diameter of the offending object.Anyway, there's my thoughts on the matter.Shoot away - I'll just duck.

author: Rasz
author_rank: Super Contributor
timestamp: December 06, 2015, 01:51:23 pm
content: Quote from: Brumby on December 06, 2015, 01:11:39 pmhttps://www.solarpaneltalk.com/filedata/fetch?id=284412&d=1432502496

author: Brumby
author_rank: Unknown
timestamp: December 06, 2015, 02:48:44 pm
content: That is really close to Dave's experience and it proves that kind of damage is possible. However, based on the apparent diameter of the 'crater' (which I'm guessing from other elements in the photos) that example actually reinforces my thoughts that it wasn't a golf ball in Dave's case.I know it's a bit of a reach without some real measurements - but that's the impression I get.Maybe Dave could take a couple of balls up on the roof and see if there is one that fits the crater.

author: Ian.M
author_rank: Super Contributor
timestamp: December 06, 2015, 03:15:01 pm
content: The other issue is: how would a ball end up hitting the roof at a high enough angle to cause symmetrical impact damage?Its unlikely to have been a high angle golf or cricket ball, as Dave hasn't commented about neighbours kids frequently needing to retrieve balls. NSW bans hunting catapults etc., and I believe Dave's in a nice enough area that there is a very low probability of it being a ball bearing hit from a slingshot fired near vertically or of some idiot firing a firearm vertically. In the UK there is always a risk of damage around Guy Fawkes night from rocket sticks and the metal rocket bodies from illegally fired marine parachute flares, but Australia doesn't celebrate Guy Fawkes night and the sale of fireworks to the general public is mostly banned, largely due to the risk of bush fires, and no such object was found. There are no traces of broken mussel or snail shells, and Australia doesn't have any indigenous tortoises, so a bird dropping their prey to crack its shell theory is also highly unlikelyIts therefore most probably ice impact damage - either a freak hailstone that may have been much larger than others in the same storm, or ice falling from an aircraft.@Dave (EEVBlog): Do you remember any bad hail storms since the previous time you were on the roof?

author: gilbenl
author_rank: Regular Contributor
timestamp: December 06, 2015, 03:19:09 pm
content: I'd bet my left foot on a cricket or baseball. I also noticed that it appears your fence/neighbors are about 1.5m away from the edge of your roof. There's also a pool within arm/bat's reach as well. Its entirely conceivable that some kids were playing catch or actually hitting balls, one went up on a high arc and came down on your panel. It then rolled and took a hop off the edge of the panel itself or those terra cotta roof tiles and landed back in their yard. They retrieved it and never thought twice...Golf ball also seems reasonable. Although small, they deform a good bit (relatively) on impact and making the crater somewhat larger than expected. You don't need to be anywhere near a golf course to see errant golf balls either. I had a friend whose windshield was shattered by one. He knew the source was a golf ball because he found it sitting on his wiper. Turns out a neighbor was hitting balls into one of those practice nets using a wedge, was set up too far back, the arc of the ball missed the net and traveled 50 or so yards to meet my buddy's windshield.The video below shows the impact deformation of a moving golf ball on a flat surface (vs. impact leaving the club face), however, this ball was probably moving considerably faster than anything you'd encounter. It does well highlighting just how much deformation capacity/elasticity a golf ball can exhibit without breaking. Okay, it may just be a cool video, too.https://www.youtube.com/embed/HTgSaEPdj-U

author: Brumby
author_rank: Unknown
timestamp: December 06, 2015, 03:29:15 pm
content: I wasn't expecting THAT amount of deformation!Is that aregulargolf ball? I would have expected the case to crack deforming that much.

author: gildasd
author_rank: Frequent Contributor
timestamp: December 06, 2015, 03:55:27 pm
content: Aliens and magnets, especially magnets.But seriously folks, when I was about 10, someone did manage to whack a cricket ball that endded in the windshield of the old school Land Rover of one of the teachers.With only one bounce.The flat glass had a plastic film on the back side.The end result was near identical to Dave's panel.

author: Rasz
author_rank: Super Contributor
timestamp: December 06, 2015, 04:20:44 pm
content: Quote from: Brumby on December 06, 2015, 02:48:44 pmI dont think Dave has the balls to do it, he is not a golfer.

author: SeanB
author_rank: Super Contributor
timestamp: December 06, 2015, 04:44:14 pm
content: Years ago I did see that a hard boiled egg ( boiled to Mil spec ie boil till the white and yolk are blue) is capable of breaking a windscreen when it hits it at 100kph.As to the golf ball, you do accelerate it from zero to 200kph in it's own diameter, so yes it has to deform a lot and survive that. Drive a tank over one and it does survive, though you may have to look for where it went when it popped out under the tread.They do not survive going through a jet turbine, though the turbine is supremely unaffected by the operation. It has to survive FOD on the runway ( small stones, errant small birds, national flowers) without incident. Geese and larger birds do tend to do damage, look at those nice RR Trent videos on YT for the aftermath.We had quite a few engines that ingested pigeons during operation, engine makes a small puff of smoke and there is no evidence aside from a few smears of blood of the bird. Even saw one that had a first stage compressor blade snap off from a bird strike, and go through the engine without any sign aside from greatly increased vibration, which went away with increased power, so the 50 minute leisurely ferry flight went down to 15 minutes at full afterburner, where it was almost gone. Came in hot, and ran out of fuel during touch down, so had to be towed off the runway. Luckily it was off for an airframe overhaul, so the engine was coming out in any case, though it came back as cargo to the service bay for investigation and overhaul.

author: RupertGo
author_rank: Regular Contributor
timestamp: December 06, 2015, 04:58:46 pm
content: Here's another link to suspected meteorite damage to a PV panel -http://www.solarcurator.com/2012/06/13/module-failure-from-an-otherworldly-source/. Of particular interest, they found the contender for the crime by running a magnet around the area.But I'd suspect a well-hooked cricket ball, from the shape and size of the depression. A decent swing plus contact can add a lot of energy and height, and the perpetrator will be keen to remove the evidence. A solitary huge hailstone sounds unlikey; that sort of hailstorm tends to get noticed. My favoured secondary explanation would be something falling from an aircraft, especially if you're in the area where the gear might be coming down prior to landing.

author: max_torque
author_rank: Super Contributor
timestamp: December 06, 2015, 05:51:38 pm
content: Would some form of thin, self adhesive, transparent stick on film not be ideal for a temporary fix?Like the stuff you use to laminate paper with etc?I'm also pretty sure that any ball that hit that panel would bounce off and go a long way, so it ain't going to be found in the gutter or probably even in the garden!

author: vodka
author_rank: Frequent Contributor
timestamp: December 06, 2015, 05:56:58 pm
content: I see the deformation of the panel solar, and it is almost perforated.I believe that the projectile (steel ball or baseball ball)path seems as anti-tank gun, a horizontal with lightness parabolic path with an impact at high speed .This can to explain the great deformation and the place where could be thrown(Somebody have a building a few more elevated than Dave's home).I suspect that somebody was doing out of the ordinary in the roof

author: Ian.M
author_rank: Super Contributor
timestamp: December 06, 2015, 06:24:56 pm
content: Its definitely a good idea to make it weather-tight to maintain the system output while the manufacturer and the insurers argue about who pays how much. Get lots of photos first. I'd say the easiest would be heavy grade clear PVC, foil taped to the rim. I'd avoid anything stick-down to the panel itself as putting pressure on it in that condition isn't a good idea, and also the weatherproofing needs to be easily removable in case the manufacturer wants to examine it.

author: l0rd_hex
author_rank: Regular Contributor
timestamp: December 06, 2015, 07:22:00 pm
content: Have you ruled outterrorism? I'm thinking para-militarized llamas armed with frozen burrito cannons. I am deadly serious about this.

author: MartinX
author_rank: Regular Contributor
timestamp: December 06, 2015, 08:17:49 pm
content: Drunken golfers did this.

author: Kleinstein
author_rank: Super Contributor
timestamp: December 06, 2015, 10:03:16 pm
content: A meteorite is rather heavy material with a high speed. This would likely give smaller impact zone and less of the big dent.Comparing this with the damage shown from the golf ball in the other video, I would get its somthing like the cricket ball of a block of ice of similar size.Also note the rather concentric rings around the impact. So likely the impact was rather vertical.

author: Ian.M
author_rank: Super Contributor
timestamp: December 06, 2015, 10:27:09 pm
content: Quote from: l0rd_hex on December 06, 2015, 07:22:00 pmMore likely Australian DSTO's combat kangaroos armed with beachballs!http://baetzler.de/humor/killer_kangaroo.html

author: EEVblog
author_rank: Unknown
timestamp: December 06, 2015, 10:40:07 pm
content: Quote from: l0rd_hex on December 06, 2015, 07:22:00 pmIt can't be ruled out.

author: EEVblog
author_rank: Unknown
timestamp: December 06, 2015, 10:41:51 pm
content: Quote from: RupertGo on December 06, 2015, 04:58:46 pm30km out from the airport.But am within a few hundred meters of a flight path.

author: Ian.M
author_rank: Super Contributor
timestamp: December 06, 2015, 10:51:14 pm
content: If my numbers are right, that means the aircraft are at about 5000' - 6000' when they fly over you, which would be consitent with ice buildups having thawed long enough to break loose. As the aluminium aircraft skin conducts heat far better than ice does, thick buildups tend to break free rather than thaw completely..See:http://www.engineeringtoolbox.com/air-altitude-temperature-d_461.html

author: chickenHeadKnob
author_rank: Super Contributor
timestamp: December 07, 2015, 01:51:27 am
content: Quote from: EEVblog on December 06, 2015, 10:41:51 pmHa - ha (sorry) blue ice it is! I know you like to sniff things now is the chance for forensic schnuffery. If this is recent damage the crater may still have the fragrance of blue sanitizer+human waste. On the other hand if it has been a-while and there have been rains...A damaged solar panel would be getting of lightly. Some twenty years ago a decrepit ancient DC-7, a four engined prop plane , lost a nose wheel and it went through the roof of an apartment building near where I used to live.

author: cdev
author_rank: Super Contributor
timestamp: December 07, 2015, 02:19:09 am
content: Once I saw a coated, "shatterproof" (tinted) glass door spontaneously shatter (but of course, the coating meant it did not explode it simply became a mess of shattered glass) because it was in full sunlight and the sun must have caused some kind of catastrophic failure due to unequal heating of the laminated materials.It was really quite spectacular. The entire thing turned into a mess of cracks in around half a second. Nobody was anywhere near it and it was shut. It was fun because I was with a bunch of scientists. We were all left awestruck by this event.It did make a funny kind of sound.

author: aroby
author_rank: Regular Contributor
timestamp: December 07, 2015, 02:45:18 am
content: Maybe an Amazon drone on a test flight dropped its package too soon ...

author: Smokey
author_rank: Super Contributor
timestamp: December 07, 2015, 03:43:34 am
content: Cricket ball? Really? It would essentially have to come from your close neighbors right? Do you have a cricket playing neighbor that is such a dick that he would carelessly launch a ball out of his yard, crack your solar panel, and not own up to it? A professional baseball home run is like 450 feet (137m). I'm not sure how far cricket balls go, but that really limits the range it could have come from (and you pretty much know the direction).Assuming it was a cricket ball, the damage and angle would look to me that someone was seriously trying to wack the crap out of the cricket ball, not just casually toss it over a fence. Is that realistic?I don't know what neighborhood you live in, but I would hate to be looking over my shoulder for all these roving bands of cricket hooligans all the time.

author: Circlotron
author_rank: Super Contributor
timestamp: December 07, 2015, 03:46:10 am
content: Light is photons.Photons have properties of both waves and particles.Radio waves are electromagnetic, just like light.Your local radio station sends electromagnetic waves.Maybe their antenna was emitting waves and *heavy rock* particles through your property at the time?

author: DrGeoff
author_rank: Frequent Contributor
timestamp: December 07, 2015, 04:07:08 am
content: Quote from: Smokey on December 07, 2015, 03:43:34 amOf course. Cricket balls are harder than baseballs.Then some kid with a tennis racquet could have whacked a golf ball up in the air (now that really flies) or a rock in the air (and probably lost a string doing that) which could come down onto a panel. A golf ball would bounce away and down the street.

author: Smokey
author_rank: Super Contributor
timestamp: December 07, 2015, 04:17:54 am
content: I get what a cricket ball is. My point was that if that was what it was, it couldn't have come from very far away. That side of his house doesn't look like it faces the street. Since you essentially know the direction, and you (probably) know who your neighbors are in that direction, what is the likelihood that one of those neighbors is a dick or has dick kids.If we are talking golf balls, the average golf drive is 200 yards (182m) so look for dick neighbors that far out.

author: Alexei.Polkhanov
author_rank: Frequent Contributor
timestamp: December 07, 2015, 04:32:36 am
content: My bet is on a golf ball. I am waiting for another episode of Myth Busters, "can golf ball do that?"Dave still have enough panels to test all plausible theories:Here is the Poll:ice - 0 votesgolf ball - 1 votebaseball/cricket ball - 0meteorite (hard to simulate?) - 0 votesbirds - 0 votes

author: zapta
author_rank: Super Contributor
timestamp: December 07, 2015, 04:39:38 am
content: Any similar pattern here?https://www.google.com/search?q=solar+panel+glass+broken&source=lnms&tbm=isch&sa=X&ved=0ahUKEwjE3ZDK9sjJAhWDt4MKHVCTA4IQ_AUIBygB&biw=1308&bih=646#tbm=isch&q=solar+panel+broken&imgrc=7lhd1wuiK1aSeM%3A

author: DrGeoff
author_rank: Frequent Contributor
timestamp: December 07, 2015, 04:41:34 am
content: Quote from: Smokey on December 07, 2015, 04:17:54 amA lot of high school kids are finished now and roaming about. It does not have to be a neighbour, just some kids wandering around the streets.

author: Cyberdragon
author_rank: Super Contributor
timestamp: December 07, 2015, 04:41:52 am
content: Quote from: Alexei.Polkhanov on December 07, 2015, 04:32:36 amI think Mythbusters got cancelled.Do they even play much golf in Australia?

author: Brumby
author_rank: Unknown
timestamp: December 07, 2015, 04:47:02 am
content: Yes, golf is a popular sport here in Australia. I don't know the actual figures, but the impression I get is that it is something similar to that of the USA, probably a bit less.Errant golf balls aren't common, but you can't rule out an idiot with no conscience.

author: Brumby
author_rank: Unknown
timestamp: December 07, 2015, 04:51:21 am
content: Quote from: Alexei.Polkhanov on December 07, 2015, 04:32:36 amPut me down for a cricket ball.... and if it is a cricket ball that did the damage, I would be looking within a 100m radius. Considering the symmetry of the damage, I agree with others that the trajectory will have been around the perpendicular. To do that and have the necessary velocity, would mean a solid whack and askiedskyed ball.

author: pickle9000
author_rank: Super Contributor
timestamp: December 07, 2015, 05:00:20 am
content: I say it's a dragonball because they can disappear.

author: Smokey
author_rank: Super Contributor
timestamp: December 07, 2015, 05:04:05 am
content: So the cricket ball was hit from the grassy knoll and made of ice so there was no cricket ball evidence left over? Are you sure it wasn't the Cubans? When is the Oliver Stone move coming out?

author: DimitriP
author_rank: Super Contributor
timestamp: December 07, 2015, 05:10:26 am
content: The ripples don't look perfectly concentric. I think that's a clue as to the object's direction.

author: Ian.M
author_rank: Super Contributor
timestamp: December 07, 2015, 05:25:29 am
content: The roof is sloped, which if we assume an impact that was closer to being perpendicular to the surface than to being glancing, offsets the possible origin zone. Probably within 50m the other side of the house and maybe 150m that side.

author: Psi
author_rank: Super Contributor
timestamp: December 07, 2015, 06:05:30 am
content: I wonder if the object might have bounced and then rolled under the panel.Might be worth a look under it

author: LabSpokane
author_rank: Super Contributor
timestamp: December 07, 2015, 06:31:59 am
content: I'm glad it wasn't anything as simple as some kid chucking a rock at a piece of glass to see if it would break.Because what really happened is the panel was damaged by falling debris from a test of my homemade anti-satellite weapon. If you find any chunks of titanium with Chinese writing on them, just keep it our little secret, OK?

author: pickle9000
author_rank: Super Contributor
timestamp: December 07, 2015, 06:50:39 am
content: Quote from: LabSpokane on December 07, 2015, 06:31:59 amAwesome, best one so far. Honorable mention to Smokey, Cubans = Awesome.

author: marber
author_rank: Regular Contributor
timestamp: December 07, 2015, 09:08:49 am
content: I think Batteriser's shipment of Fail has arrived... ;-) The EE equivalent of a dead horse head perhaps?

author: GNU_Ninja
author_rank: Regular Contributor
timestamp: December 07, 2015, 09:20:25 am
content: Interesting stuff ...http://etheses.bham.ac.uk/4263/1/Chen-X13PhD.pdfForensic fracture analysis:https://www.ncjrs.gov/pdffiles1/nij/grants/241445.pdfMy moneys on a cricket ball

author: Muttley Snickers
author_rank: Unknown
timestamp: December 07, 2015, 10:07:44 am
content: Skylab.....Although a big pain in the arse having a panel smashed it's probably better for that to have occurred rather than whatever caused the impact breaking a roof tile and causing flooding to part of the house during the next severe rain storm, could have happened I suppose, it got close anyhow.

author: VK3DRB
author_rank: Super Contributor
timestamp: December 07, 2015, 11:05:08 am
content: Quote from: DrGeoff on December 06, 2015, 04:22:02 amLG = Lucky Goldstar. That is their real name. The same makers of the crappy Goldstar video recorders and a host of other low end (or "no" end) rubbish dumped into places like K-Mart, and with some models, no spare parts available from anywhere. Even Goldstar's component placement machines were toys compared to the beautifully engineered Japanese workhorses, like Juki.Sorry to disappoint, but Dave's Lucky Goldstar panels are low end.Goldstar is synonymous with crap.

author: DenzilPenberthy
author_rank: Frequent Contributor
timestamp: December 07, 2015, 01:14:35 pm
content: I'm going to put in another vote for a cricket ball fired from the grassy knoll next-door. I'm sure it wasn't done on purpose but I remember as a kid if you smash someone's greenhouse with a ball you crap your pants, hide the ball and say you were playing indoors all day

author: Ian.M
author_rank: Super Contributor
timestamp: December 07, 2015, 01:39:04 pm
content: It would be interesting to know the maximum hail stone size that the panel is rated to withstand. The density of ice is 0.9340 g/ml and of a golf ball is about 1.15 g/mL. A golf ball is 42.7 mm diameter, weighs less than 45.93g i.e less than a 46mm diameter sphere of ice and at terminal velocity should not be capable of breaking a panel that can withstand 46mm hail stones.As large hailstones are not uncommon in the Sidney area, I would argue that any panel designed for unprotected outdoor installation that cannot withstand a 50mm hailstone at terminal velocity is not of merchantable quality.http://www.bom.gov.au/nsw/sevwx/hailfact.shtml

author: zapta
author_rank: Super Contributor
timestamp: December 07, 2015, 01:57:23 pm
content: Quote from: wilfred on December 07, 2015, 09:54:06 amIt was causes by climate change.

author: jancumps
author_rank: Unknown
timestamp: December 07, 2015, 02:49:20 pm
content: Lightning?

author: nixfu
author_rank: Unknown
timestamp: December 07, 2015, 02:53:32 pm
content: Obviously giant aussie spider related damage.

author: Wytnucls
author_rank: Super Contributor
timestamp: December 07, 2015, 02:57:12 pm
content: Does a soprano live next door?

author: GNU_Ninja
author_rank: Regular Contributor
timestamp: December 07, 2015, 03:10:21 pm
content: Quote from: Wytnucls on December 07, 2015, 02:57:12 pmI think Dave might have noticed

author: zapta
author_rank: Super Contributor
timestamp: December 07, 2015, 03:48:57 pm
content: Quote from: Wytnucls on December 07, 2015, 02:57:12 pm... or a uBeam lab?

author: warp_foo
author_rank: Unknown
timestamp: December 07, 2015, 04:06:33 pm
content: Quote from: Cyberdragon on December 07, 2015, 04:41:52 amThere will be one final season in 2016. 8 or 10 episodes, I think.m

author: tszaboo
author_rank: Super Contributor
timestamp: December 07, 2015, 06:38:09 pm
content: I think it was the invading army of the G'Gugvuntts or the Vl'hurgs testing their super-weapon on your massive scale energy collector mega complex.Quote

author: jnissen
author_rank: Regular Contributor
timestamp: December 07, 2015, 06:53:07 pm
content: Quote from: Brumby on December 06, 2015, 03:29:15 pmThat is not a normal hit on the ball. Look again at Youtube and there are a lot of golf hit slow motion video's. Nothing comes close to the compression initially shown.BTW - I will also vote for a cricket/baseball type of hit. As a kid I can recall playing croquet and hitting one of those wooden balls way up in the air. Could have killed someone if it came down on their head. Your neighbors have any of those?Luckily I have not had any issue with my own solar panels being damaged from impacts. I was warned that if the panels are on a single story home you can still get errant rocks thrown up by lawn mowing. If you have anyone who mows the grass with a power mower they can hit rocks and launch a projectile at very high speed. Anyone with a lot of grass that needs to be trimmed nearby? Not familiar with suburban life in your area but if that is common it could also be a cause.

author: LaurenceW
author_rank: Frequent Contributor
timestamp: December 07, 2015, 07:56:16 pm
content: -1 for baseball-size hail. We had a MEGA hail storm four years back - it smashed car windows, dented car panels and wrote cars off, smashed greenhouses, shredded trees and damaged tiles on dozens of house roofs (we lost 20+ tiles), but the PV panels were untouched! Indeed, I'd go so far as to say that the panels[protectedthe section of the roof that they cover! And you kinda KNOW when a hailstorm like that hits. I think a one off (natural) hail stone is a non-starter.However, the event did cause me to consider the need to replace a panel at some point - and here's the rub. My top-of-the-line Sanyo (now Panasonic) panels arealreadyno longer manufactured!This may be common in this fast-moving market. So any replacement will stick out like a saw thumb (if your array is visible). Moral; if you need a replacement panel, get one while you still can!And bypass diodes or not, I tend to find that when one panel goes into shade, it really kills the output of the whole string. It's VERY noticeable, beyond the loss of output of one panel alone. Pretty sure that once the rain gets in, you'll lose the output of that one panel.

author: keethrax
author_rank: Contributor
timestamp: December 07, 2015, 09:42:10 pm
content: I think the batterizer guys flew over and chucked a AA on him.

author: DrGeoff
author_rank: Frequent Contributor
timestamp: December 07, 2015, 09:53:08 pm
content: Quote from: keethrax on December 07, 2015, 09:42:10 pmOf course!Inter-Continental Batterizer Missiles!

author: Muttley Snickers
author_rank: Unknown
timestamp: December 07, 2015, 10:09:06 pm
content: Quote from: DrGeoff on December 07, 2015, 09:53:08 pmCouldn't have been them, they have a reputation for missing targets.....

author: georges80
author_rank: Frequent Contributor
timestamp: December 07, 2015, 11:41:40 pm
content: Not the issue here...There are arrays of panels in the bush in oz along the rail that runs to Kal and also is the line for the Indian Pacific. Lots of ore and other stuff travels on that line. There's a gravel access road between the solar array (that powers gear in the siding) but it's all round gravel.Anyhow, we stop at the siding somethings since there's a rain water tank fed from the roof of the siding, tap to access the water so great to top up our own tanks. Looking at the solar array (which is tilted somewhat at the rail since the rail is to the north of the array) you can see quite a lot of rock shards (more like spear heads, NOT gravel) that have impaled themselves in various panels of the array. There's a wire mesh 'shield' near the panel, so we assume that was installed after they found the damage on the panels. Presumably enough of the array continues to work that no need for replacement of the damaged panels has been necessary, yet...We have assumed that those rocks are shot at very high speed when the train goes by, not sure if due to some of the rocks (falling out of the cars) ending up on the rail and then being spit out when a wheel tries to go over the rock. Pretty scary since I would not want to be standing (or in a vehicle) anywhere near that array (or similar distance) to the rail line.The tempered glass doesn't shatter other than around where the rock penetrates. Some are partially visible on the rear side of the array. Some serious momentum at work...cheers,george.

author: Macbeth
author_rank: Super Contributor
timestamp: December 07, 2015, 11:47:20 pm
content: Bogans for neighbours and drongos for their kids. It's that simple.

author: continuo
author_rank: Frequent Contributor
timestamp: December 07, 2015, 11:47:55 pm
content: Check if there's any suspicious looking toolbag around.http://www.dailymail.co.uk/sciencetech/article-1087092/Oops--Female-astronaut-loses-tool-bag-Shuttle-spacewalk.html

author: Smokey
author_rank: Super Contributor
timestamp: December 08, 2015, 01:17:33 am
content: I got it... I figured it out!!It was.... Dave Jones long lost brother....Casey Jones!!https://youtu.be/7_6KMGB_Pkw?t=2m7s

author: Brumby
author_rank: Unknown
timestamp: December 08, 2015, 01:24:29 am
content: Quote from: jnissen on December 07, 2015, 06:53:07 pmI did check out other videos of normal golf ball impacts and it is very clear that the impact in the link given is extreme. I just found it difficult to believe that, in the case of such an extreme impact, the casing did not fail.The other thing is, that the surface this ball (in the video) hit was completely unyielding (in any practical sense). Dave's glass panel was far less so. The deformation and failure of the glass would have reduced the peak deceleration by orders of magnitude over the video example - and the shape of the ball would not have changed much. Certainly less than is visible in the other golf ball videos I saw.While the point of the reference to ball deformation (that it would result in damage indicating a diameter larger than the projectile at rest) is clearly sound, I doubt the forces involved would have produced much of a variance. Certainly nowhere near enough for a golf ball to leave a cricket ball sized imprint, IMHO.

author: TooOldForThis
author_rank: Regular Contributor
timestamp: December 08, 2015, 02:50:37 am
content: Can't this be 'fixed' by putting a sheet of polycarbonate over the broken glass and sealing the edges with aquarium cement? The polycarbonate will absorb some of the energy, but it will keep the water out (assuming it's not already full of water).

author: mtdoc
author_rank: Super Contributor
timestamp: December 08, 2015, 03:44:06 am
content: Quote from: Smokey on December 08, 2015, 01:17:33 amDriving that train, high on....

author: Tandy
author_rank: Frequent Contributor
timestamp: December 08, 2015, 01:44:33 pm
content: You are all wrong, it must have been Segan throwing his lego to see if it would fly

author: Brumby
author_rank: Unknown
timestamp: December 09, 2015, 02:29:38 am
content: Wow ... Such a good arm on a little tacker...!!

author: crispy_tofu
author_rank: Super Contributor
timestamp: December 10, 2015, 08:46:29 am
content: That's one big Lego...

author: Kalvin
author_rank: Super Contributor
timestamp: December 10, 2015, 02:48:46 pm
content: Quote from: EEVblog on December 06, 2015, 04:23:16 amThen, its a beer can. Foster's.Or the kids were playing with something round and hard, and oops. Those things happen from time to time.

author: Gunhaver
author_rank: Newbie
timestamp: December 12, 2015, 07:33:33 pm
content: Hi All. I'm curious if anyone else did some back of the envelope calculations? I read through this thread and didn't see any guesses to the properties of the impact object. I decided to work the problem with two different sets of assumptions.Firstly i assumed the object was a bullet-type and based my assumptions on data for a 7.62 NATO bullet (11g, terminal velocity of 90 m/s both from wikipedia). I also assumed the glass has a shattering pressure limit of 70MPa (pulled from a random technical presentation of nominal tempered glass). I also assumed an impact duration of 1ms before the object bounced away at the end of the impact event. I also assumed the tip of the bullet hits first and deforms until the diameter of the impact surface is 7.62 mm. Using all of these values, and the formula for net force during an impact (Fnet = delta momentum / delta time), I calculated that the pressure imparted by the impact object was around 17.37 MPa. The lower bound i found for shatter pressure of tempered glass was 7 Mpa, so this number is in the right ballpark i think. This tells me that my assumptions are close. I also assumed a relatively low-velocity impact from essentially a vector normal to the surface of the glass after reading this summary of glass shattering forensics on the FBI's website:https://www.fbi.gov/about-us/lab/forensic-science-communications/fsc/jan2005/index.htm/standards/2005standards7.htmI thought about this all so more, and i decided to also work the problem with the assumption that the impact event imparted a pressure 70MPa, and then figure the mass of the object based on that. This made more sense to me because we know at least a minimum amount of pressure was imparted, so it is a safer assumption. In this case, i assumed a spheroid object, which gives a drag coefficiant of 0.47 through air. I also assumed 70% relative humidity, 70 deg F (21 C), and an altitude of 19 feet (about 6m) EGM96 MSL. I also assumed the object's radius to be 0.5 inches this time around (about 1.27 cm). I also assumed an impact duration of 0.7 ms this time because wolfram alpha informed me that the average impact duration of a baseball hitting a bat is 0.7 ms. I could be way off here on the duration.I should point out, that i read this thread after i assumed the radius, and there is a post in this thread that explains how the radius of the object is likely greater than the white crushed area on the glass. Even so, i think my numbers are still the right magnitude. Given all of the above assumptions, i now calculated the impact object's mass to be around 387.018 grams (or about 13 ounces, or 0.85 lbs). 13 ounces sounds right to me (it agrees somewhat with my first calculation), and i think it really points to a meteorite type object.I could take this even further and calculate a probable radius for the final resting place of the object. It seems we could use the concentric ring pattern to extrapolate the impact angle, and then we can simply figure the angle relative to the earth. Then it would be a matter of figuring a range for momentum transfers to the glass (there would be an upper bound less than 100% transfer because the object was not embedded and is not sitting right next to the panel). At any rate, this would give us a range of trajectories that should draw a line on the ground. Treat this line as a diameter of a circle, and then you have a grid for Dave to search for a meteorite type object. I think it would be very cool if we predicted where the object would be, and then Dave actually found it.Feel free to tear my calculations apart and make them better (or just point out what is wrong). It is all back of the envelope, so i'm not pretending any of it is accurate beyond magnitude level analysis. Does anyone else have any values? I'm very curious.This was a very entertaining way to spend my morning when i'm feeling sick. Thank you for reading this far!

author: Macbeth
author_rank: Super Contributor
timestamp: December 12, 2015, 08:44:08 pm
content: Quote from: Kalvin on December 10, 2015, 02:48:46 pmNope. Beer cans are far to light when empty, and no self respecting bogan would chuck a full tinnie at the roof without consuming the fine malt liquor first. Far more likely the drongo chucked an empty stubbie of VB instead.

author: EEVblog
author_rank: Unknown
timestamp: December 12, 2015, 09:05:20 pm
content: I have been contacted by LG Australia, and they said that not a single one of these panels has ever shattered in over 300,000 installed in this country. Not by hail or anything else.

author: Lightages
author_rank: Unknown
timestamp: December 12, 2015, 09:11:45 pm
content: Aren't you lucky then!

author: Ian.M
author_rank: Super Contributor
timestamp: December 12, 2015, 09:39:20 pm
content: Quote from: Macbeth on December 12, 2015, 08:44:08 pmBlame the Murray Crays!http://www.youtu.be/-6FSoKdPneo

author: Macbeth
author_rank: Super Contributor
timestamp: December 12, 2015, 09:57:10 pm
content: Quote from: Ian.M on December 12, 2015, 09:39:20 pmThose critters are just protecting you from the Drop Bears and the deadly Cassowaries

author: DrGeoff
author_rank: Frequent Contributor
timestamp: December 12, 2015, 10:49:22 pm
content: Quote from: EEVblog on December 12, 2015, 09:05:20 pmAnd none of their washing machines ever caused a fire either ...

author: Stray Electron
author_rank: Super Contributor
timestamp: December 12, 2015, 10:55:01 pm
content: Quote from: EEVblog on December 12, 2015, 09:05:20 pmE-bay it!

author: WN1X
author_rank: Unknown
timestamp: December 12, 2015, 11:10:16 pm
content: Quote from: EEVblog on December 12, 2015, 09:05:20 pmI would think that would be enough for them to come out and see the damage first hand. And, perhaps, provide a free replacement panel

author: Brumby
author_rank: Unknown
timestamp: December 13, 2015, 02:09:43 am
content: Quote from: EEVblog on December 12, 2015, 09:05:20 pmAn impressive record. I would think they would be rather interested to examine it to try and determine the how and why of it's failure.There is one reservation - and that is whether they are being absolutely honest about the zero failure . I say that not to make such an accusation, but to allow for the possibility that a marketing spin had been placed on the statement. I will add that I believe such an action is rather unlikely since, in today's internet culture, there is almost nowhere to hide.I am interested to hear what LG does next - and whether Dave is up for a warranty claim or an expense.

author: tszaboo
author_rank: Super Contributor
timestamp: December 13, 2015, 06:55:10 pm
content: Quote from: EEVblog on December 12, 2015, 09:05:20 pmSo there is 1 broken out of 300.000 and you said the glass is the most expensive part of the panels?I smell over engineering. I would take a few percent discount for even a ten-hundred fold failure easily.

author: LabSpokane
author_rank: Super Contributor
timestamp: December 13, 2015, 08:23:41 pm
content: Quote from: EEVblog on December 12, 2015, 09:05:20 pmDave,LG may not have seen a shattered panel, but it's a little hard to believe that this is the first time it's ever happened.And for those criticizing the cost of the glass, that's actually one of the key efficiency features of a panel: the glass needs to be thin in order to be as transmissive of light as possible. Surely that has to come at a cost. I wouldn't be surprised if there's a coating involved.

author: edpalmer42
author_rank: Super Contributor
timestamp: December 13, 2015, 08:44:04 pm
content: Quote from: LabSpokane on December 13, 2015, 08:23:41 pmHow many times have you phoned tech support and heard "No one has ever reported that problem before"?Yeah, right.Ed

author: ruffy91
author_rank: Regular Contributor
timestamp: December 13, 2015, 09:47:58 pm
content: At my university there is a project with panels following the sun. There are 10 of them on a pole about 3m high. One night all of them shattered and the damage looked very similar.It was kids wo threw stones at them (ca. 100g-500g range).

author: EEVblog
author_rank: Unknown
timestamp: December 14, 2015, 12:53:00 am
content: Quote from: LabSpokane on December 13, 2015, 08:23:41 pmThat's all we have to go on.They have not seen one, and no reports from any installers in Oz.QuoteSolar glass is also very low iron content which helps with the transmittance.

author: EEVblog
author_rank: Unknown
timestamp: December 14, 2015, 12:54:43 am
content: Quote from: Brumby on December 13, 2015, 02:09:43 amThey are sure it's a large vertical impact.QuoteThey want to give me a free replacement. I just have to get it installed.

author: coppice
author_rank: Super Contributor
timestamp: December 14, 2015, 01:17:05 am
content: Quote from: EEVblog on December 12, 2015, 09:05:20 pmThe statement from LG is meaningless. The best they could reasonably claim is that they are unaware of a shattered panel. Impact damage like Dave's panel isn't going to be repaired under warranty, so the failure would never be reported to LG. I wonder how many single panels they have sold to previous domestic purchasers of array sized bundles of panels? That might say something about the number of failures due to damage.

author: Brumby
author_rank: Unknown
timestamp: December 14, 2015, 02:01:17 am
content: Quote from: EEVblog on December 14, 2015, 12:54:43 amGood news.

author: EEVblog
author_rank: Unknown
timestamp: December 14, 2015, 02:02:58 am
content: Quote from: coppice on December 14, 2015, 01:17:05 amOf course that is what they meant.

author: IanB
author_rank: Super Contributor
timestamp: December 14, 2015, 02:04:54 am
content: Quote from: coppice on December 14, 2015, 01:17:05 amI rather doubt that. Warranty or no, if I had a panel break I would be calling the manufacturer to report it.Sure, with cheap items I would write off the loss as one of those things, but with expensive items I sure as heck would follow up on a failure.

author: coppice
author_rank: Super Contributor
timestamp: December 14, 2015, 02:29:54 am
content: Quote from: IanB on December 14, 2015, 02:04:54 amIf I had a panel damaged by the weather I would be claiming under warranty on the basis of the panel's fitness for purpose. Are you really saying you would complain about accidental high impact damage? Would you complain to Michelin if someone slashes your car tyres? Some things are outside the manufacturer's control, and most people are reasonable enough to accept that.

author: Paul Moir
author_rank: Frequent Contributor
timestamp: December 14, 2015, 02:43:12 am
content: Quote from: coppice on December 14, 2015, 02:29:54 amSure, but if you say have a surplus in your warranty contingency fund, perhaps you would want to spend it on some good will? Can be good for both the manufacturer and the unfortunate.

author: coppice
author_rank: Super Contributor
timestamp: December 14, 2015, 02:45:00 am
content: Quote from: Paul Moir on December 14, 2015, 02:43:12 amWell, if Dave's free replacement panel gets significant publicity maybe we'll find just how many people have had a panel broken.

author: coppice
author_rank: Super Contributor
timestamp: December 14, 2015, 02:52:26 am
content: Quote from: blueskull on December 14, 2015, 02:46:12 amSome products are sold with an explicit inclusion of accidental damage cover. Most are sold with anything beyond "fair wear and tear" explicitly excluded. Top brands may look at accidental damage, and cover cases where the product failed too easily, but don't expect too much from them.Apple is a poor example to choose. For a long time they refused warranty claims for any phone with the humidity stickers triggered. That included pretty much every phone sold in a humid climate.

author: SeanB
author_rank: Super Contributor
timestamp: December 14, 2015, 04:27:13 am
content: Samsung here has a 2 free repairs under warranty policy on the larger units sold from around mid last year. Covers a single screen replacement or a single glass replacement, irrespective of the cause. They do however show on the invoice the amount you would otherwise have had to pay for this, along with the reminder that the next one is not free. Seeing as they are the largest seller in the smartphone market this is a good selling point.

author: station240
author_rank: Unknown
timestamp: December 14, 2015, 05:00:20 am
content: Quote from: EEVblog on December 14, 2015, 12:53:00 amI'm sure installers have broken them during transport/installation.Possible it is the first reported to them as damaged after install.

author: coppice
author_rank: Super Contributor
timestamp: December 14, 2015, 05:12:39 am
content: Quote from: EEVblog on December 14, 2015, 12:53:00 amLow iron glass as an option for domestic glazing makes a big difference to the price of windows. With solar panels having become very price sensitive, I wonder how many actually use this type of glass?

author: Someone
author_rank: Super Contributor
timestamp: December 14, 2015, 07:47:44 am
content: Quote from: coppice on December 14, 2015, 05:12:39 amIn volume most glasses are cheap, multilayer wideband antireflective coatings for the glass would be the expensive part (while being cheap to put on the silicon its self). There are even cheaper plastic films you can use instead of glass but they have comparatively poor impact protection. Losses in the protective layers/coatings are a very small part of the efficiency of the assembled panel so there is lots of wiggle room to use less than ideal parts.

author: Someone
author_rank: Super Contributor
timestamp: December 14, 2015, 07:57:07 am
content: Here is a good example of the challenges of AR coatings:http://info.adimec.com/blogposts/bid/40330/Anti-reflection-coatings-improve-accuracy-for-high-performance-camerasSo with a good quality AR coating you could push an extra 4-6% light through to the cells (which will heat up more etc so wont see the whole gain) so that 4% on an 18% assembly only brings you up to 18.8%. Small gains but the wider literature says prices are coming down enough that its becoming routine for solar panel assemblies, but while they dont mention the typical improvements or efficacy of the coating its just another meaningless marketing point which may or may not actually improve performance of the panel.

author: Rasz
author_rank: Super Contributor
timestamp: December 14, 2015, 08:34:08 pm
content: Quote from: coppice on December 14, 2015, 02:29:54 amof course he would, this is why insurance companies invented new type of insurance just for the US market, the 'I dont give a f' type where you can claim it if you 'accidentally' threw your phone into the wall during heated argument, or dropped it in the toilet.Quote from: blueskull on December 14, 2015, 02:46:12 ammm the Apple myth is strong with this onehttps://support.apple.com/en-us/HT204104no, you need a special moron insurance for that

author: thm_w
author_rank: Super Contributor
timestamp: December 15, 2015, 12:27:24 am
content: Quote from: Someone on December 14, 2015, 07:47:44 amWe used a plastic/epoxy coated panel for a while at work and it was horrific. The coating is soft so scratched easily, and dirt would stick or embed itself in the surface.I'm sure there are better parts out there, but I can't think of where you'd ever want to use the cheap panels we got.

author: rs20
author_rank: Super Contributor
timestamp: December 15, 2015, 02:05:54 am
content: They use Physical Vapor Deposition (PVD) using a hard vacuum to put the silly decorative metallic finish on plastic kitchen blenders; it becomes economic with large quantities. And very nice antireflective coatings are commonplace in camera lenses.With that in mind, I'd be very surprised if the glass used in solar panels wasn't coated (at least on the underside) -- it seems like a very easy efficiency win for a very low recurring cost? I know the glass panels are larger than camera lens elements, but still.Also, regarding antireflective coatings being delicate: yeah, making a coating that is both durable, not overly sticky, and antireflective is a difficult compromise. But don't forget that the underside of the glass is a potential reflection point. Even if they only coated the underside of the glass, that still halves your reflection losses, and the side of the glass that sees the outside environment is dead-standard uncoated glass (or differently coated).

author: LabSpokane
author_rank: Super Contributor
timestamp: December 15, 2015, 06:30:49 am
content: Quote from: blueskull on December 15, 2015, 05:14:11 amYou need to keep in mind that Dave is not a utility trying to repurpose a brownfield site. Dave bought the LG panels due to their quality and efficiency. Trying to optimize the output from a fixed size rooftop is a slightly different value proposition than utility-scale solar. Dave knowingly paid a premium and got great service when he had a problem.

author: Chris Jones
author_rank: Regular Contributor
timestamp: December 16, 2015, 01:45:46 pm
content: Quote from: rs20 on December 15, 2015, 02:05:54 amThe encapsulant ("glue") between the glass and the cells is usually EVA or sometimes silicone, but in any case it has a similar refractive index to glass so there is not much reflection from the interface between the glass and the encapsulant and not much point in applying anti-reflective coatings on the underside of the glass.

author: Ian.M
author_rank: Super Contributor
timestamp: December 16, 2015, 03:55:56 pm
content: What can be done with a shattered solar panel? Once the new panel is up and working, maybe a teardown? Can the shattered glass be effectively re-bonded by resins like the one in the video near the start of the topic? Can the glass be removed and the panel hacked up and re-glazed to power small low voltage projects?

author: gildasd
author_rank: Frequent Contributor
timestamp: December 22, 2015, 04:09:48 pm
content: Quote from: blueskull on December 22, 2015, 09:15:41 amUV Resistant epoxy, no filler, slow reactant, very thin layer.

author: Seekonk
author_rank: Super Contributor
timestamp: December 22, 2015, 04:49:05 pm
content: Free panels! I can see people sticking on those shattered glass decals and taking a picture.

author: Kleinstein
author_rank: Super Contributor
timestamp: December 22, 2015, 05:40:57 pm
content: A simple AR coating (just 1 or 2 layers) is not expensive. You can get this on windows at a rather low extra costs. Coating window panes is standard (at least in Europe) - in small quatities you may have to pay extra for an uncoated gals.Even if its only some 3 % of more energy gained, the cost of the coating is likely less than 3% of the panel, and higher efficiency panels also need less area and mounting.Sould not be a golf ball, as the panels should withstand hail of comparable size and weight und thus therminal speed. This one looks like not just shatterd but way over the design limit.

author: gildasd
author_rank: Frequent Contributor
timestamp: December 22, 2015, 06:50:38 pm
content: I found proof of what happened...