EEVblog #844 - Solar Panel Replacement - Page 1
Forum section: electronics / general

author: EEVblog
author_rank: Unknown
timestamp: January 25, 2016, 03:38:48 am
content: Dave replaces the shattered LG Mono-X solar panel on his home rooftop solar power system.http://pvoutput.org/list.jsp?userid=22501http://www.lg.com/au/commercial/mono-x-solar

author: Brumby
author_rank: Unknown
timestamp: January 25, 2016, 03:40:19 am
content: I was wondering how this was going...

author: Brumby
author_rank: Unknown
timestamp: January 25, 2016, 03:52:33 am
content: So, all done. Has the next day 'Sun test' proven successful?

author: Alexei.Polkhanov
author_rank: Frequent Contributor
timestamp: January 25, 2016, 03:59:11 am
content: Hmm, I think "the projectile" may still be inside the panel. David maybe able to find it and if not I would have poured an opaque silicone at the place of impact and once it is solidifies I would try to lift it off carefully to get an imprint of whatever object hit it.

author: EEVblog
author_rank: Unknown
timestamp: January 25, 2016, 04:07:17 am
content: Quote from: Brumby on January 25, 2016, 03:52:33 amIt works.

author: richms
author_rank: Contributor
timestamp: January 25, 2016, 04:17:31 am
content: That dent out the back is pretty epic!Mine are going in on the 5th here. "2.6kw" system on the garage roof, hope I don't have anything like that happen since its a 45degree roof so not something that you can just walk on.

author: Brumby
author_rank: Unknown
timestamp: January 25, 2016, 04:50:54 am
content: Quote from: richms on January 25, 2016, 04:17:31 amYeah - I thought so too.For those who wish to study it....

author: Alexei.Polkhanov
author_rank: Frequent Contributor
timestamp: January 25, 2016, 04:57:52 am
content: Perhaps the object that hit the panel still in there beneath that plastic wrap?

author: SL4P
author_rank: Super Contributor
timestamp: January 25, 2016, 05:08:48 am
content: My guess would be a 12mm or 1/2-inch nut or similar.Falling from 15000 feet - would make a serious dent - dissipated by the glass and panels.Maybe not so lucky if it hit you on the head.And if it hit the glass at an angle - it would bounce a fair distance away at 'terminal velocity'... tens of metres?

author: Stonent
author_rank: Super Contributor
timestamp: January 25, 2016, 05:16:51 am
content: Rinoa Super Genius did a video on trying to reseal some panels he got at the scrap heap.

author: HackedFridgeMagnet
author_rank: Super Contributor
timestamp: January 25, 2016, 06:05:33 am
content: I'm sure the shutdown procedure would be AC off first then DC. Its just to minimise arcing and thus help with the longevity of DC isolator.The shutdown procedure is written on the white plaque on or near the inverter.Startup is the opposite but I don't think it really matters.Underneath one of the mid clamps should have been an Earth plate, when the new panel goes on, this one need to stay sitting in the correct position. This just pierces the oxide layer of the panel to attach the chassis to earth.Just done my solar installer course, I know this stuff.

author: EEVblog
author_rank: Unknown
timestamp: January 25, 2016, 06:11:36 am
content: Quote from: HackedFridgeMagnet on January 25, 2016, 06:05:33 amNot when you switch it off with bugger all power generated. I wasn't shutting the system down.I only needed to isolate the DC side to work on it.

author: HackedFridgeMagnet
author_rank: Super Contributor
timestamp: January 25, 2016, 07:35:15 am
content: Ok I agree that waiting for the sun to go down is an effective way to prevent arcing when isolating the DC.Unnecessary as it probably is I would normally shutdown the whole system.ps. It is ok to short a solar panel or even the whole string.Just one a range of tests done by the installer to check the integrity of the system.

author: mtdoc
author_rank: Super Contributor
timestamp: January 25, 2016, 08:02:16 am
content: A blanket or tarp thrown over the panels is a tried and true method as well.Besides, proper rated DC shutoffs can be shut off while live without issue.

author: coppice
author_rank: Super Contributor
timestamp: January 25, 2016, 08:04:44 am
content: The air must be clean where Dave lives. Most cities have enough goo in the air that in 2.5 years it would have formed a sticky film over the back of the old panel, and a thick layer of dust would have stuck to the goo.

author: coppice
author_rank: Super Contributor
timestamp: January 25, 2016, 08:11:45 am
content: Quote from: mtdoc on January 25, 2016, 08:02:16 amCovering works, but covering a big area on your own can be pain, unless there is zero breeze. Although Dave waited until the generation had fallen, it had not ceased. He waited long enough for the current to fall, but there would have still been a fairly high voltage present. He might as well have turned off the isolator and done the work during the day, when there was more light to see by. The panels were installed in full sunlight. They can be serviced that way too.

author: G7PSK
author_rank: Super Contributor
timestamp: January 25, 2016, 08:51:00 am
content: The shape of the dent on the back of the panel suggests a bolt rather than a nut or a cricket ball, could even have been a spent bullet they often impact sideways as the tumble and will travel for miles if shot into the air.

author: EEVblog
author_rank: Unknown
timestamp: January 25, 2016, 09:02:03 am
content: Quote from: HackedFridgeMagnet on January 25, 2016, 07:35:15 amOnce it's installed, yes.I wouldn't do it with those connectors, you could pit the contacts. That's the whole point of the connector warnings.

author: EEVblog
author_rank: Unknown
timestamp: January 25, 2016, 09:03:05 am
content: Quote from: G7PSK on January 25, 2016, 08:51:00 amThis ain't the USA

author: EEVblog
author_rank: Unknown
timestamp: January 25, 2016, 09:05:48 am
content: Quote from: coppice on January 25, 2016, 08:11:45 amThe eye has a massive dynamic range, plenty to see by.

author: coppice
author_rank: Super Contributor
timestamp: January 25, 2016, 09:06:14 am
content: Quote from: EEVblog on January 25, 2016, 09:02:03 amCovering a big array with a blackout sheet may be a pain, but covering one panel to kill the flow of current while you replug things isn't.

author: EEVblog
author_rank: Unknown
timestamp: January 25, 2016, 09:06:22 am
content: Quote from: coppice on January 25, 2016, 08:04:44 amWelcome to Australia

author: coppice
author_rank: Super Contributor
timestamp: January 25, 2016, 09:12:38 am
content: Quote from: EEVblog on January 25, 2016, 09:05:48 amSure, but you said you hit a snag with a stuck bolt. If that had been more serious and taken you into darkness you would have ended up finishing the job in the next day's sunlight anyway. Its summer in Australia, so I guess it was pretty hot during the day. Working at dusk when the temperature is more comfortable makes a lot of sense, but these things have to be serviceable at any time of day.

author: chickenHeadKnob
author_rank: Super Contributor
timestamp: January 25, 2016, 12:24:04 pm
content: You said you had a bugger of a time getting those hold down bolts off. They look like they may be stainless steel. I discovered to my frustration, decades before the internets could help with preventive advice, that stainless hardware which isn't coated in anti-seize can gall and self weld dam near instantly.

author: putz182
author_rank: Newbie
timestamp: January 25, 2016, 01:07:47 pm
content: Call me crazy, but don't believe it was an impact.The glass cracking effect can be a shadowing effect result.Watch the 2:20 minute video. There is a first shadowing in the last panelYou should check for hotspot when that happen.You should also forward power the panel in the lab and check for defective cell as well.

author: EEVblog
author_rank: Unknown
timestamp: January 25, 2016, 01:32:26 pm
content: Quote from: putz182 on January 25, 2016, 01:07:47 pmStevie Wonder could tell it's an impact

author: Brumby
author_rank: Unknown
timestamp: January 25, 2016, 02:40:38 pm
content: As if the front view wasn't enough - the ding out the back isn't a heat blister!

author: Barny
author_rank: Frequent Contributor
timestamp: January 25, 2016, 03:51:34 pm
content: It could have been an little meteorite.The deformation an the backside looks like an impact with really high speed.If its something from a plane it would impact with terminal velocity (250 to 300 km/h).That wouldn't be worse than than hail if its small enough to disappear.

author: Kleinstein
author_rank: Super Contributor
timestamp: January 25, 2016, 08:03:09 pm
content: Ice from a plane is very much like hail with blue color and without the rain and usually one 1 relatively large piece. If large enough it can damage the panel as the part gets heavier and the velocity goes up.For sealing I would use some kind of epoxy that is UV resistant- even if the whole thing is crackes all over it should be enough to seal the really broken zone. There is a plastics foil between the gas and the cells itselt.

author: Don Hills
author_rank: Regular Contributor
timestamp: January 25, 2016, 08:56:19 pm
content: Quote from: chickenHeadKnob on January 25, 2016, 12:24:04 pmIn addition, stainless steel touching aluminium will corrode the aluminium. I learnt the hard way, using stainless steel screws to hold the elements on aluminium Yagi antennae.

author: HAL-42b
author_rank: Frequent Contributor
timestamp: January 26, 2016, 01:15:39 am
content: Quote+1 for micrometeorite. Whatever it was it surely must have left some residue in the glass. Time to bust out the microscope

author: Barny
author_rank: Frequent Contributor
timestamp: January 26, 2016, 07:30:05 am
content: Quote from: Kleinstein on January 25, 2016, 08:03:09 pmThe impact dent shows clearly that it was a small, fast piece.If it blue ice get big enough to damage the panel, the whole panel would be bend.(Slow piece with high mass.)

author: jnissen
author_rank: Regular Contributor
timestamp: January 26, 2016, 05:13:33 pm
content: Jarts! I remember those wonderful projectile toys from my youth!Dave you scored a major donation with that panel. They are not low cost at all! Way to go.+1 for destructive test to see if you can find any fragments in the panel for what hit it. The back sheet and front glass is laminated to the solar cells inside so there is NO WAY you will save the cells by removing the glass. In fact all the glass will be glued to the cells and why you don't have shards all over your roof in the first place.They really seal these things well for any environmental contaminants. It's not just glass, cells, backsheet. All that space is filled with a clear glue like material.

author: Vgkid
author_rank: Super Contributor
timestamp: January 26, 2016, 09:09:09 pm
content: Just watched it, that replacement would have been alot more interesting if it was not at the end. Middle maybe.

author: f4eru
author_rank: Super Contributor
timestamp: January 27, 2016, 08:59:07 pm
content: That H+S radox wire is one of the best available wire....Made in Switzerland... (by nude virgins ?)http://www.hubersuhner.com

author: Stonent
author_rank: Super Contributor
timestamp: January 28, 2016, 09:27:07 am
content: Quote from: EEVblog on January 25, 2016, 09:06:22 amNearly the same size as the US, but about 8% of the people. Makes sense.

author: rs20
author_rank: Super Contributor
timestamp: January 29, 2016, 10:08:10 pm
content: Ithoughtthese panels had some sort of clear resin filling the space between panel and front glass; to (among other things) reduce the refractive index change through that cavity and thus reduce reflections and improve efficiency.I wonder if that's why there's no obvious water ingress down the bottom, and why the glass shards are all staying together (although this particular point can be explained by a film as well).

author: bitwelder
author_rank: Super Contributor
timestamp: January 30, 2016, 02:48:44 pm
content: Quote from: HAL-42b on January 26, 2016, 01:15:39 amWhy micro? Could it have been asmallmeteorite (i.e. a bit more than a few mm of diameter) of irregular shape, with a... microhorn on the side that faced the impact, so it was this microspike that pierced the panel, but there was also the (accelerated) mass of the whole small meteorite that thrusted it forward to cause even the metal back of the panel to bend?