Flexible vs Non-Flexible Panels?

YodaRules

Other than weight and cost are there other things to consider?  Only reason for looking at flexible (Solar Blvd Solar Cynergy 120W Flex Mono Panel) is weight. Weight is not posted on their website so I emailed asking how much. Response was about 12 pounds which I find hard to believe when most 100W flexibles are around 5 pounds.

Originally, my thought was 2 Renogy 150W panels until I saw the 120W Flex panel. I keep flip flopping and need to zero in on my selection then purchase. Part of my thought process is the ability to maybe add another panel later on down the road.

Cost for 2 Renogy 150W is $389 and 2 Solar Cynergy 120W Flex is $277 (have to pay shipping here). For $122 I get 60W more with Renogy along with the additional combined weight of 53 pounds. These panels will not be attached to my RV instead I will build PCV stands and have on ground. Renogy does come in a compact little 39.5"x 39" almost square and the Flex is 46.5" x 21.3 -- oh, the decisions.....

Appreciate any help in my decision making.........     

BB.

In times past... Flex panels were about 1/2 as efficient at glass+crystalline silicon solar panels--So you would need 2x the surface area of flex for the same amount of power. For ground mounted arrays with "unlimited" area, that is not a problem (other than 2x more money for racking and wiring a 2x larger array). For RV applications with little roof space, collection efficiency would usually win out.

Renology panel 39.5"x 39" / 150 W = 10.3 sq inch per Watt
Cynergy panel 46.5" x 21.3" / 120 W 8.3 sq inch per Watt
SolarWorld SW-275 Mono 4.0 65.95" x 39.4" / 275 Watt = 9.4sq inches per Watt

The Cynergy is not the traditional "thin film" panel (low efficiency) but is a mono-crystalline panel with very thin crystalline solar cells that are "flexible" because the are sliced so think (my guess).

So, from an efficiency point of view--The Cynergy are the most efficient. And only has a 1 year warranty (at least the Ebay site I found). Also, these panels are probably much more susceptible to damage from sharp objects (thin plastic vs 1/8" tempered glass). A typical glass panel will have 20+ year warranty (other flex panels seem to have 5-10 year warranties). Of course, at $1 per Watt, you may be doing your own warranty costs (who knows if any solar company will be around 20+ years these days).

I don't know if the panels you are looking at are "frameless" or not... The frameless flex panels are (I think) supposed to be mounted on a solid surface (boat deck/roof, etc.). So, that would make mounting a bit more of a problem.

Also note, it is not really the weight of the two panels that you should worry about for your racking--Both are similar square inches--And it is wind loading that you need to design for. You should be designing for 40 to >100 lbs per square foot (snow/wind loading). Your panels are around 7 sq feet, meaning that 280 to >700 lbs from environmental loading per panel.

Light weight plastic pipe racking may blow over in a major wind storm (unless you are looking a much heavier PCV pipes). Again, a guess on my part--I do not know your specific plans.

-Bill

YodaRules

Thanks Bill, you reply is very informative. Reason for lighter panels is only for me lifting, carrying, storing. Handling the Renogy 150W panels at 26.5 pounds is the very most I want to lift and lug around (would consider attaching some sort of carry handle on the side. The SolarWorld SW-275 you mentioned comes in at 33 pounds and is as tall as I am so that is a no-go for me.

Still mulling over..........

Again, thanks!!!

BB.

The large Solar World panel was just a handy/relatively efficient panel that I figure out the sq inch per Watt for a relative figure of merit.

I agree that glass and framed solar panels are a real pain to move around. And, unless you mount them to the roof of your RV and/or make a folding "roof porch/awning" that is fixed to your RV (and in hot locations, you probably want to park under shade/trees) the lighter weight panels may be the better/only option.

You can go with the frameless versions--But those run the risk of folding/creasing on you--So you made need to make a frame/carrying/racking to hold them safely anyway--Which may end up just being as much trouble as framed units anyway.

When moving solar panels daily/weekly for trips--If they last a few years without something happening (blown down in wind, dropped, dragged behind RV as you drive away, stolen, etc.)--You should probably count yourself lucky and more careful than I.

-Bill

YodaRules

Solar Cynergy is not framed.  It does have pre-drilled holes on both sides to add framing and it wouldn't add much to the weight. But, you brought up a good thoughts ........ weighing under 8 pounds would have more opportunity for a big wind to blow them over and get scratched and easier for others to pick up and walk away with. I am careful but, at times tend to get in a hurry and you know what that does............

Learning toward Renogy 150W.... and if I add another panel later on will have 450W which if perfect for my Class B+ and 3 or 4 day dry camping at a time.

Patsy

xyzHollyxyz

Here is my "answer" to making the flex panel more rigid - 2 small PVC pipes bolted through the built-in panel grommets.
Works well for me.

 

BB.

Make sure to strain relieve the cables where they exit the panel (such as mounting a cross piece of PVC and anchor the wiring there)... Their anchoring is usually not very strong and subject to failure from flexing.

-Bill

xyzHollyxyz

THANKS! Great hint! 

Just changed out the cap for a right-angle and came up with this cross piece.
How would you recommend anchoring the leads - plain ol' Gorilla tape? 

xyzHollyxyz

Can a small inverter be used upside down?

 

BB.

For the wiring--I would suggest that you tape/bundle tie the cables on the side pieces next to where they enter the panel. The run from the panel to the end piece is pretty long--Easy to snag when moving around.

Does your inverter have a fan? If there is no fan, I would suggest that inverter be mounted "vertically on a wall" for convection to help move air (hot air rising). If the inverter has a fan, then would be less of a need to worry about mounting (always make sure you have good air circulation--Don't mount in a small cabinet. It will overheat).

Are you thinking of putting in a that plastic box? If so, that will restrict airflow and run the the risk of overheating and fire (setting the plastic box on fire). For electrical installations, you should always look at what is under your system components. You do not want them mounted over flammable materials (cardboard boxes, carpet, etc.). A metal shelf underneath and sheet rock behind is not a bad idea for a cabin/home.

-Bill

Photowhit

xyzHollyxyz said:

Can a small inverter be used upside down?

 

Check with your inverter company. I know the prosines are designed to mount any direction except as a chimney, with the fan at the top or the bottom. They even make the display so that it can be turned to be upright with the way it's mounted.