Flexible or non flexible - panel advise needed... 3 questions

[EdRedBird]

So winter coming up it seems like the IDEAL time of year to get the benefit of the sun
I have a DC50 MPPT from Renogy just missing the panels
And to simplify plug and play I am thinking of sticking to the renogy brand.
I am comparing these 3 yokes:
Solid : 100W, 41.8 x 20.9 x1.4 in and Eficiency 22% https://www.renogy.com/100-watt-12-volt-monocrystalline-solar-panel-compact-design/
Flexible 100W 43 x 23 x 0.1 in and Eficiency 15.7% https://www.renogy.com/100-watt-12-volt-black-division-lightweight-monocrystalline-solar-panel/
Flexible 100W 48.0 x 21.6 x 0.08 in and Efficiencey 14.9% https://www.renogy.com/100-watt-12-volt-flexible-monocrystalline-solar-panel/

Solid Pannels would mean additional bracketing system wheras the flexible would go straight on the roof
Is there any drag / fuel consumption benefit from one or the other (I could also fix any bracketing system to roofbars avoiding drilling in the roof)
Solid pannels I could mean i could tilt them when parked and get more out the rare rays
Flexible would be more stealthy

Q1: Any recommendations
Q2: Then there is this eficiency thing... I mean they are all 100W so whats the deal with that ? are they not all 100W

And lastly the output cables 12 AWG or 14 AWG ...will this dictate lead thickness if I add panels (AND as these are only 2.5 ft long)
Q3: How thick does the cable to my MPPT box needs to be (Does that cable need to double and Triple

 

[daveandsan]

I think you will find that flexible panels don’t have good longevity, but I am sure someone will be along soon that knows what they are talking about.

 

[Phill D]

I originally fitted a 100w flex panel to the roof it lasted around 3 years and it was a pig to remove.
I am sure they have improved but unless I had no choice personally I would use solid panels.

 

[Guigsy]

Having bit of an airgap under the panel has other advantages. The cooling means the solar cells don't overheat, so you keep maximum output in sustained strong sunlight. And it also shades the roof, keeping it a bit cooler inside.

 

[Jimbohorlicks]

I saw someone using a flexible panel as a portable panel,very light easily moved around and probably easy to store in the MH when travelling. Just a thought.

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[jumar]

Me and gus-lopez or better still gus-lopez and I....Betta English...fitted a 200w tilting panel last winter....I must say...it's bloody incredible..low sun....good harvest....high summer sun good harvest....this together with my folding tri-panel is producing a huge amount of solar to replenish my batteries as they recharge my bike batteries...Rooftop panel not elevated as the sun is still high in the the Iberian sky.....don't travel with panel on bike rack...it dazzles the drivers behind me...

 

[jockaneezer]

My flexi 150w panel only lasted 18 months and was a pig to get off, the replacement didn't last that long.I I
I was up on the roof the other day and the replacement panel is delaminating quite badly now. I need to replace it with a solid one.

 

[jumar]

My flexi 150w panel only lasted 18 months and was a pig to get off, the replacement didn't last that long.I I
I was up on the roof the other day and the replacement panel is delaminating quite badly now. I need to replace it with a solid one.

Get a solid Ridged one...cheap easy to fit and very efficient...

 

[Nigel Crompton]

Get a solid Ridged one...cheap easy to fit and very efficient...

Only easy to fit if you're comfortable with ladders. I'm past all that.
In a dialog with Renogy customer support as to the best mounting techniques to use on RV's
Renogy's warranty is 5 years for flexible panels (or at least the 175w I want)

 

[jumar]

Only easy to fit if you're comfortable with ladders. I'm past all that.
In a dialog with Renogy customer support as to the best mounting techniques to use on RV's
Renogy's warranty is 5 years for flexible panels (or at least the 175w I want)

You don't need to be ladder safe to fit a Solar Panel....just call a friend...that's what I did....I did have my left hand in a cast at the time though.....and I have a really good friend too..

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[autorouter]

Q2: Then there is this eficiency thing... I mean they are all 100W so whats the deal with that ? are they not all 100W

If you calculate the area of each, you will see that the area of the flexible panels is a bit bigger than the solid panels. If it takes more area to produce 100W, they are less efficient.

 

[Guigsy]

The scariest bit about fitting solar panels is the hole for the cable.

 

[Lenny HB]

Fit a flexible and replace in 2 years if it lasts that long and will leave a right mess on the roof having spent hours getting it off.

Fit a ridged panel and forget about it for 20 years.

 

[Two on Tour]

We have a couple of rigid panels on our van and when I wanted to fit some more panels on the rear of our van roof I needed to consider the extra weight on our rear axle over-hang loading our rear axle, so I went for semi-flexibles to save weight.
Being aware of failures of semi-flexibles due to overheating when bonded to a roof with no air gap for cooling and along with the expansion and contracting of the panels causing conductor joints to fail, I went for mounting my semi-flexible on lightweight multiwall polycarbonate roofing sheet which gives stiffness to the panel and also allows airflow to dissipate heat away from the panels.
They have been up there for 3 years or so now and neither has failed, so either I'm just lucky or my mounting method is keeping them alive.
If weight was not a consideration, then I would have gone for rigid panels rather than the semi-flexibles.

 

[Two on Tour]

The scariest bit about fitting solar panels is the hole for the cable.

After you have drilled as many holes into and through our van roof, then it becomes second nature.

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[bobandjanie]

I know the early Baird flexible panels were trouble, but we fitted 2 x 100w in 2013 on our last panel van and still working perfectly when we sold it April 2018, we fitted the same on our present panel van March 2018 2 x 100w flexi panels mppt regulator 2 x 80 amp gel batteries.
Been out cycling today in Spain a warm 31°c when we got back to the van it was 43°c inside the van, plugged the bike batteries in the inverter pulling 455w until both batteries fully charged, just had dinner and all vehicle batteries are full these flexible panels are 4 and a half and see more and heat than most.
I have no quibble they do what it says on the box, when they don't I will tell you. Bob.

 

[Howard B]

Flexi panel on our PVC was still working when I replaced at 5 years old. Only changed it as I wanted to go from 100w to a Renology175w. Happy with it so far. Took me a couple of hours to remove the old and refit the new one.

 

[Nigel Crompton]

..... I went for mounting my semi-flexible on lightweight multiwall polycarbonate roofing sheet which gives stiffness to the panel and also allows airflow to dissipate heat away from the panels.


View attachment 665318

Am I correct in thinking from this photo that the polycarb is just bonded to the panels for stiffness, but the panels are actually mounted using brackets bolted to the eyelets ?

 

[Nigel Crompton]

You don't need to be ladder safe to fit a Solar Panel....just call a friend...that's what I did....I did have my left hand in a cast at the time though.....and I have a really good friend too..

Billynomates, me..

 

[Two on Tour]

Am I correct in thinking from this photo that the polycarb is just bonded to the panels for stiffness, but the panels are actually mounted using brackets bolted to the eyelets ?

Correct, I made my own mounting blocks which I bonded to our roof to raise the panels and backing clear of the roof and the panel is bolted down via the panel eyelets for easy removal of the panels if needed.

The twin wall polycarbonate backing is to give stiffness and to allow airflow under the panels.

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[ceejayt]

Had flexi panels - had to replace them after two years as just rubbish return. Now have proper panels and they are great

 

[cyberyacht]

I've had semi-flex on both my motorhomes without issue although I PX'd the first after two years and only had the current one for just over a similar period. On a previously owned caravan I fitted a cheapish aluminium backed panel to a 'floating' roof and it failed after 12 months. Flexible is so that they can be fitted to gently curved surfaces but none of them like being constantly flexed. The better quality 'resin encased' type are the one to go for. The polycarbonate bonded method referred to a few posts back seem a good idea whilst retaining the lighter payload advantage.

 

[Minxy]

I saw someone using a flexible panel as a portable panel,very light easily moved around and probably easy to store in the MH when travelling. Just a thought.

I have a 50w one for that very purpose.

 

[Minxy]

If you calculate the area of each, you will see that the area of the flexible panels is a bit bigger than the solid panels. If it takes more area to produce 100W, they are less efficient.

Not necessarily as the semi-rigid ones usually have a larger edge area than a rigid.

 

[Nigel Crompton]

Correct, I made my own mounting blocks which I bonded to our roof to raise the panels and backing clear of the roof and the panel is bolted down via the panel eyelets for easy removal of the panels if needed.

The twin wall polycarbonate backing is to give stiffness and to allow airflow under the panels.

That's me sorted then the local brico stocks the polycarb sheet. Thinking cap on for bracket fabrication ...

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[jumar]

Billynomates, me..

I'm sure as near neighbours a quick call would be all that's needed....

 

[Nigel Crompton]

I'm sure as near neighbours a quick call would be all that's needed....

Cheers Martin .... but I'm going flexi and I can manage those OK, I think.

 

[Lenny HB]

Cheers Martin .... but I'm going flexi and I can manage those OK, I think.

But will you be able to manage in one to two years when they pack up. May be a bit more agro now now to fit ridged panels but they are fit and forget.

 

[gwyntaxi]

I think you will find that flexible panels don’t have good longevity, but I am sure someone will be along soon that knows what they are talking about.

Correct they seem to have a short lifespan of around 3-4 years people I have spoken to have had 2 sets of panels each only lasting 4years at a time better off with rigid panels.

 

[jumar]

Cheers Martin .... but I'm going flexi and I can manage those OK, I think.

No problem Nigel....but please be aware that here on fun there there are members who are more knowledgeable than most...this does not include me I must add...I have recently asked technical advice about my pending lithium swap....and without such information, I could have made mistakes that were both critical and costly...

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