Solar The Solar Panel Thread

mikerezny · Jan 24, 2020

Ok, thanks for the photos.
Your portable solar assembly consists of two panels wired in parallel.

Each of these panels consists of two sub-panels wired in series. You can tell this because, in the terminal block, there are three silver threads coming from the solar cells. One sub-panel terminates on the LH and centre terminals, the other on the centre and RH terminals.
There is a bypass diode across each of the sub-panels.

This is a quite common setup. But I can't see the point in having the bypass diodes. If one sub-panel is shaded, then the panel will only produce about 10V which is not enough to drive a solar regulator.

This panel would be an ideal candidate for wiring the two panels in series and feeding them into an MPPT controller. The cables appear to be on the light side for carrying 10A over any distance. Then leave the TPS controller for managing the roof panel.

But that doesn't solve the mystery of the parallel panels. Still two candidates: blocking diodes or a faulty controller.
Still need some better tests with all panels in reasonable sunlight without connection to the controller.

cheers
Mike

jazzeddie1234 · Jan 28, 2020

Yes the current could be much higher, but only (for example) when the batteries are discharged and the solar controller is bulk charging, or where you have something like an inverter drawing lots of current. Otherwise the batteries may charged and the controller switched to trickle charging

Boots in Action · Jan 28, 2020

jazzeddie1234 said:
Yes the current could be much higher, but only (for example) when the batteries are discharged and the solar controller is bulk charging, or where you have something like an inverter drawing lots of current. Otherwise the batteries may charged and the controller switched to trickle charging

Agreed @jazzeddie1234 . Two of the readings give a good indication of what is happening at that moment. Panel voltage of 18 volts indicates that the load is indeed light (or batteries are fully charged). Panels are rated at Vmp and Imp ie 16.4V x 6.7A which equals the rated panel output of 110 watts. With low or no load, Vmp rises and the total output of only 4A (1A from each panel in parallel) certainly indicates trickle charging or Float situation. Also Vmp tends to remain higher when panels are cold. IMHO, a good position to be in.

Brente1982 · May 19, 2020

When people are fitting panels to the roof of their expandas, are you screwing and glueing (sikaflex 221/227) or just glueing? I've seen peel rivets used by some people on other forums.

Drover · May 19, 2020

When they reskinned Big Mal after the hail damage the solar was replaced with glue and screw onto the tin roof and not into frame work as far as I could tell, alloy angle has a large foot print also........ With a glass roof I would certainly glue but don't think I would rivet.

Crusty181 · May 19, 2020

Brente1982 said:
When people are fitting panels to the roof of their expandas, are you screwing and glueing (sikaflex 221/227) or just glueing? I've seen peel rivets used by some people on other forums.

Screwed and glued with a Polyurethane or a Polymer adhesive. Polymer is my choice, but Polyurethanes favourite "family of substrates" is alum on fibreglass. Adhesive both holds and seals, and the screws compress the joint whilst its curing. Position the brackets, drill the holes, clean thoroughly with a purpose cleaner say Presol or similar, scuff the mating surfaces, pump the sealer into the holes in the roof and mound it up, coat the perimeter of the fixing face of the bracket and encircle the drill holes. Screw it down and then seal around the angle with the forced out excess sealant to stop any pooled or forced moisture from making its way under the angle at any point

The smaller angle just to the rear of the panel is the original Jayco factory 150w panel mount (which Im still using). That white substance would very likely be just Jayco's goto Roof and Gutter silicone. The angle is screwed just through the glass roof skin ie theres no structure whatsoever under Jayco's choice of location for the 4 x small angles so the panel has been flopping about on the floating roof skin. Add that to 60k km including many 1000s km of corrugations and the panel was still there.

Drover · May 19, 2020

At least on yours @Crusty181 you can remove the panel, the "Professionals "

that redid Big Mals panels used brackets that have an extrusion on the inside which they riveted the panel to, they then screwed and glued the whole panel to the roof, all very good but if I want to remove the panel I have to remove the bracket from the roof first......... while some may think a theft deterent I think more likely it meant they didn't have to measure out where to fit the brackets, just plonk panel down, glue and screw......... :censored:

Crusty181 · May 19, 2020

Drover said:
At least on yours @Crusty181 you can remove the panel, the "Professionals " that redid Big Mals panels used brackets that have an extrusion on the inside which they riveted the panel to, they then screwed and glued the whole panel to the roof, all very good but if I want to remove the panel I have to remove the bracket from the roof first......... while some may think a theft deterent I think more likely it meant they didn't have to measure out where to fit the brackets, just plonk panel down, glue and screw.........

You have an adequate air gap underneath tho ???

Boots in Action · May 19, 2020

Crusty181 said:
You have an adequate air gap underneath tho ???

Correct @Crusty181 , a very important point! Air flow is just as important too - somewhere for hot air to escape. Heat on panels (portable panels in the open) can rise to 50C or over in hot sunny conditions, but there is obviously plenty of air flow around both surfaces of panel with them. Not so easy on roof fixed panels. The loss is calculated at 0.5% for every 1C above 25C (the standard temp for specs). So not only is it the direct sun heat, but anything else that attracts heat and holds it near panels. Voltage is the main thing affected and that reduces total output power in watts. So keep them cool.

Drover · May 19, 2020

Crusty181 said:
You have an adequate air gap underneath tho ???

Oh yeah, plenty of room for sparrows to fly under otherwise I would have lifted it up and done it properly, since I don't anticipate replacing the panel in the near future it can stay like it is, besides if I was replacing it I would assume its stuffed so just hit it with a knockometer to get at the tek screws....... As you can see its a professional job by the liberal use of sealant............
Damn this thread now I have a compulsion to do a decent job on it as the damn sealant is going orange peel........thankfully too much rain about and by the time it has left I will have forgotten about it.

Boots in Action · May 19, 2020

Drover said:
Oh yeah, plenty of room for sparrows to fly under otherwise I would have lifted it up and done it properly, since I don't anticipate replacing the panel in the near future it can stay like it is, besides if I was replacing it I would assume its stuffed so just hit it with a knockometer to get at the tek screws....... As you can see its a professional job by the liberal use of sealant............
Damn this thread now I have a compulsion to do a decent job on it as the damn sealant is going orange peel........thankfully too much rain about and by the time it has left I will have forgotten about it.

View attachment 65139

Looks like plenty of gap @Drover and with those heavy brackets (6mm+), it will be strongly mounted. Pity about all the sealant. You never know what mysteries are underneath. Globs of sealant can cover a multitude of sins!! But if it hasn't leaked by now, you may be alright until the sealant deteriorates.

Drover · May 19, 2020

It was all new roof and fittings 2 years ago which I checked over fully been good to date though I did pull out their ensuite vent as it was crap and fitted my own design which alliws fan access without dusmantling the whole thing...

Crusty181 · May 19, 2020

Drover said:
Oh yeah, plenty of room for sparrows to fly under otherwise I would have lifted it up and done it properly, since I don't anticipate replacing the panel in the near future it can stay like it is, besides if I was replacing it I would assume its stuffed so just hit it with a knockometer to get at the tek screws....... As you can see its a professional job by the liberal use of sealant............
Damn this thread now I have a compulsion to do a decent job on it as the damn sealant is going orange peel........thankfully too much rain about and by the time it has left I will have forgotten about it.

View attachment 65139

So the panels are screwed up through the horizontal under the panel frame ??? Thats a bit silly, though the side would have been a perfect water proofing partner with the bracket to roof fixings located under the panel and out of the direct uv. I put the flat of the front edge brackets of mine under the panel to protect the sealant

Brente1982 · May 19, 2020

I assume jayco, will infact mount the factory 120w panel at the ends, instead of the side of the panel? Which would be a PIA as I intend to take said factory panel off and replace with 3x Victron 175w poly panels which are within 6mm of the coast to coast panel width. If they place the mounts on the side of the panel, then all good. If not, I'm screwed

Crusty181 · May 19, 2020

Brente1982 said:
I assume jayco, will infact mount the factory 120w panel at the ends, instead of the side of the panel? Which would be a PIA as I intend to take said factory panel off and replace with 3x Victron 175w poly panels which are within 6mm of the coast to coast panel width. If they place the mounts on the side of the panel, then all good. If not, I'm screwed

Putting 3 x new panels on, i wouldnt get factory panel at all, just get junction box terminated on the roof. Jayco mounting a panel is only going to be an inconvenience, better starting with a blank canvas i suspect. You have nothing to gain by jerking around with a mounted panel you never wanted ???

Brente1982 · May 19, 2020

Crusty181 said:
Dont get the factory panel at all, just get junction box terminated on the roof

Ive tried, and the dealership i want to go through says it cant be done. They are by far the cheapest aswell. (other dealers have included solar deletion in their quote which is about $250 off the price)

Crusty181 · May 19, 2020

Brente1982 said:
Ive tried, and the dealership i want to go through says it cant be done. They are by far the cheapest aswell. (other dealers have included solar deletion in their quote which is about $250 off the price)

If other dealers will do it, are they not lying and theyre just playing games. What about if you pay for and they just leave it on the bed

Brente1982 · May 19, 2020

All i know is, even without the panel deletion, this dealership is still a long way cheaper than the others.
Before i sign the paperwork ill talk to them again about it and a couple of little tweaks to the quote.

If they can get it not installed, even better. But its not the be all and end all at the end of the day

Crusty181 · May 19, 2020

Brente1982 said:
All i know is, even without the panel deletion, this dealership is still a long way cheaper than the others.
Before i sign the paperwork ill talk to them again about it and a couple of little tweaks to the quote.

If they can get it not installed, even better. But its not the be all and end all at the end of the day

Which dealer are you leaning toward

Brente1982 · May 19, 2020

Page Bros Seaford.

Bayswater and Gippsland are the same price but dearer than Page Bros

Solar The Solar Panel Thread

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