I purchased a 200w flexible solar panel and has worked well for the last 2 years but I want to add another 200w but have noticed on all the ebay shops that sell the exact same Sunpower panel, that they have this notice;
Do not wire the flexible solar panel in parallel or in series to avoid damage or shortened lifespan
Do not glue the panel on top, either mount with a velcro attachment or else. Leave a space underneath for the back panel to breath
I not sure why you can't wire them in parallel or series if they are the exact same panel.
Could it be that there are many configurations of panels and are worried that a miss-match could damage the panels?
I will be running thru a redarc 30amp Mppt so thats covered.
I have mounted mine with air gap, so the bottom ones not a problem.
-- Edited by Jenko1 on Thursday 14th of September 2017 10:25:33 PM
I purchased a 200w flexible solar panel and has worked well for the last 2 years but I want to add another 200w but have noticed on all the ebay shops that sell the exact same Sunpower panel, that they have this notice;
Do not wire the flexible solar panel in parallel or in series to avoid damage or shortened lifespan
Do not glue the panel on top, either mount with a velcro attachment or else. Leave a space underneath for the back panel to breath
I not sure why you can't wire them in parallel or series if they are the exact same panel.
Could it be that there are many configurations of panels and are worried that a miss-match could damage the panels?
I will be running thru a redarc 30amp Mppt so thats covered.
I have mounted mine with air gap, so the bottom ones not a problem.
-- Edited by Jenko1 on Thursday 14th of September 2017 10:25:33 PM
Hi Jenco
I am not sure and I do not use flexible panels either. But I think it is to do with the construction of the active semiconductor layer with the multiple diodes incorporated directly into the panel surface. This perhaps makes them more prone to failure and shorting particular with high temperatures, like any semi conductor.
Like any panels there can be large voltage differences between them when one is in shade and the others in full sun. Sounds like they are marginal in coping with that situation. Most normal panels and diodes are rated at 1000 Volts voltage to accommodate the worst case that might happen on the roof.
So the answer is to only follow the instructions if all else fails, sorry !
Jaahn
-- Edited by Jaahn on Monday 18th of September 2017 03:38:59 PM
Another thing to look for in flexy's.
have it dead flat. At whatever angle you mount it.
Variations of angles over the surface,
WILL give variations of Output to battery.
I know some we were comparing on the yacht coach houses yrs ago.
Had quite a variation in outputs alongside the fixed on mine and others.
Same time. Same place\direction pointing.
As you moved it. you could see changes.
Probably way too late, but a coat of car polish on the panel stops any bird splat etching and acid rain fall out from a few of the dirtier smoke stacks, including the exhaust from older diesel engines. If you use either the aluminium mesh from the pretend type security doors or Thermoclear as a backing, then bolts through the eyelets to hold the panel to the frame, they work brilliant. I have a mate torture testing one of each type for the last 18 mths and they have gone skating face down across rocks, bitumen car parks, in the lake salt water a few times and put out and back away every day and although they look a tad worse for wear, they still work fine.
That at least eliminates the surface finish from having an effect on output and rough treatment wrecking them, so still testing the latest theory as to why multiple panels mounted on a roof have some fail while others survive. I even had one van that had been used to clear trees judging by the roof. 2 of the rigid panels were stuffed, shattered and frames twisted, quite few of the flexibles had deep marks where they had been dragged under branches with enough load to damage the thermoclear under the panels, yet these panels still worked and other unmarked ones didn't. We replaced them all, hopefully I'll get a chance over Christmas/New Yr to get them out and try to find out just what it is that kills some panels but not others.
T1 Terry
__________________
You can lead a head to knowledge but you can't make it think. One day I'll know it all, but till then, I'll keep learning.
Any links to any sites or products is not an endorsement by me or do I gain any financial reward for such links
The upgraded cells reportedly offer low reverse-bias breakdown voltage to improve performance in shady and dusty conditions, and better temperature coefficient to increase energy harvest in hot environments.
-- Edited by oldtrack123 on Saturday 11th of November 2017 12:30:10 AM
The upgraded cells reportedly offer low reverse-bias breakdown voltage to improve performance in shady and dusty conditions, and better temperature coefficient to increase energy harvest in hot environments.
-- Edited by oldtrack123 on Saturday 11th of November 2017 12:30:10 AM
A tad late Peter, but what do you mean by this statement? Do you mean the reverse bias is too low to stop a reverse current flow so the modules are overheating because they are becoming a heat blanket rather than a current generator?
T1 Terry
__________________
You can lead a head to knowledge but you can't make it think. One day I'll know it all, but till then, I'll keep learning.
Any links to any sites or products is not an endorsement by me or do I gain any financial reward for such links
The low reverse bias ,while it gives more power from the panel ,means they are less tolerant to reverse current flow, so we get the recommendation not to parallel
Not so much that they become a thermal blanket as that reverse current may not be spread evenly over all the cells but form local hot spots resulting in failed cells
Only logical reason why they say not to parallel
On that over thread I am trying to get the latest AS3000:2017
But Every thing I have read to date says the position still is that ordinary duty flexible cable as used in common extension leads shall not be used for FIXED wiring.
Of course there are many types & grades of flexables with different insulations types /grades ,such as XPL
But stay tuned until I get AS3000 2017 , Because ordinary duty [extension lead ]cable ,definately was not approved anywhere in the world for fixed wiring use
I very much doubt that the reference ,if any ,in AS3000 2017 refers to "ordinary extension "lead cable
To flex panels can be fitted where solid panels wonât fit . On curves etc . Btw the way I look and glueing to roof ? Especially an alloy or steel roof . There is a heat sink effect going on here . Which doesnât happen on solid panels . What other way are they connected if not parallel or series ? Yes heat is an issue . But I could be said they have done there job by the time it gets really hot ?? I have thought of adding flex con curves or areas I need for access . ?
The low reverse bias ,while it gives more power from the panel ,means they are less tolerant to reverse current flow, so we get the recommendation not to parallel
Not so much that they become a thermal blanket as that reverse current may not be spread evenly over all the cells but form local hot spots resulting in failed cells
Only logical reason why they say not to parallel
On that over thread I am trying to get the latest AS3000:2017
But Every thing I have read to date says the position still is that ordinary duty flexible cable as used in common extension leads shall not be used for FIXED wiring.
Of course there are many types & grades of flexables with different insulations types /grades ,such as XPL
But stay tuned until I get AS3000 2017 , Because ordinary duty [extension lead ]cable ,definately was not approved anywhere in the world for fixed wiring use
I very much doubt that the reference ,if any ,in AS3000 2017 refers to "ordinary extension "lead cable
Thank you for that Peter, that could explain a lot of things and I missed reading that about the reverse bias being reduced or the penny might have dropped a lot earlier and saved us a few $$ as well. I have been adding a blocking diode for each panel when connected in parallel after having to replace a few failed units and this seem to have stopped the failures, but time will tell.
On that other forum Dibs (Mr Glasses I think he calls himself here) posted a photo of one of the infamous light weight panels that came mounted to a sheet of aluminium, these had a very high failure rate, and it is mounted to checker plate, still has full output after more than 2 yrs so that rules out the theory I put forward that difference in expansion was tearing the modules apart, so it looks like I got that one wrong. This panel is a single panel so it can't suffer back-feed from the other panels in parallel, so this might support the cause Peter has put forward and the addition of blocking diodes for each panel could be the solution.
As far as the extension cable, the electrical inspector has been out to check on the wiring carried out by the local sparkie and gave it all the tick of approval so he hasn't knocked the use of flex cord in a few spots where it was more practical than the 2 core and earth white stuff.
I reckon the inspection was more curiosity than a safety audit, he wanted to have a look at an actual off grid set up with grid back up and petrol driven alternator to direct battery charge as a further back up if the mains were not available.
The whole 3 way switch cutting the neutral was a real head spin but that is a matter for a different subject, yet another clash between MEN system hard wired to the mains and a transportable premises that becomes a plug in appliance when it suits the standards so there can be a line drawn between one standard and the other
I can see even more dramas coming up as the standards try to catch up with the changing world
T1 Terry
__________________
You can lead a head to knowledge but you can't make it think. One day I'll know it all, but till then, I'll keep learning.
Any links to any sites or products is not an endorsement by me or do I gain any financial reward for such links
Well at last , we seen to agree on some of my theories
Lets Hope there can be some more
Yes ,a bit /big difference between plugged in & fixed wired sources
I would have thought your electrician would be aware of the requirements for switching of electrically isolated, standby sources. even with inverters
Not sure if that System is totally "OFF grid , but if it is not there should be no change to the MEN system
but I assume you are using a low voltage system with the batteries & a low voltage inverter
Change over switch [Manual or AUTO ??] to change from mains to battery powered inverter.
That sort of thing is covered in the in AS3000 : 2008
It would be treated exactly the same as a permanently wired in generator emergency supply.
New Standard is around $460
So I am still trying to find something, not going to spend that much, I have a lot of snippets of that Standard But nothing relative to normal extension lead flex cables in wall /fixed wired
Every thing so far is based on Ordinary extension cable is not to be used for fixed.permanent wiring as the insulation is not up to code requirements
Not TPS insulated & sheathed as used in usual 230V fixed wiring,
Spoke to son ,who went to some seminars on the new Standard, he said it was not mentioned @any time that he can remember
I may have to wait until he decided to spend the money
-- Edited by oldtrack123 on Saturday 9th of December 2017 05:33:39 PM
Well and truly off topic now, but the inverter auto switches the mains straight through (if available) when/if the battery voltage drop to a programmable preset voltage and the inverter becomes a battery charger, then reverts to battery power at a slightly higher voltage that is also programmable. The 3 way switch in in the main power box and only there as a back up if the whole battery/inverter system falls over so they are not left without power when everyone else has power. The owner requested that because the grid connected solar is off line more than it's online so he has very little faith in anything that has the word "Inverter" attached to it. The other purpose is a safety factor, the inverter power can be switched off at the main power box so any sparkie working on the house wiring is warned via clear labelling to switch both the mains switch to off and the 3 way switch to the 0 position to isolate all power from the house.
T1 Terry
__________________
You can lead a head to knowledge but you can't make it think. One day I'll know it all, but till then, I'll keep learning.
Any links to any sites or products is not an endorsement by me or do I gain any financial reward for such links
