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drboyd · 03-02-2014, 09:10 PM

Quote:

Originally Posted by lewster

GS-100 and GS-135 panels from AM Solar are mono-crystalline.

See? The Lewster knows what he's doing! Heat's an issue there in Florida, too!

idroba · 03-02-2014, 09:52 PM

I would not get too excited about polly vs. mono solar panels. You might want to look at this article about the differences between panels:

Which Solar Panel Type is Best? Mono-, Polycrystalline or Thin Film?

Here are three quotes from that article:

1. Monocrystalline solar panels tend to be more efficient in warm weather. Performance suffers as temperature goes up, but less so than polycrystalline solar panels. For most homeowners temperature is not a concern.

2. Polycrystalline solar panels tend to have slightly lower heat tolerance than monocrystalline solar panels. This technically means that they perform slightly worse than monocrystalline solar panels in high temperatures. Heat can affect the performance of solar panels and shorten their lifespans. However, this effect is minor, and most homeowners do not need to take it into account.

3. Both mono- and polycrystalline solar panels are good choices and offer similar advantages. Even though polycrystalline solar panels tend to be less space-efficient and monocrystalline solar panels tend to produce more electrical power, this is not always the case. It would be nearly impossible to recommend one or the other by not examining the solar panels and your situation closer.

Bottom line: re read #3 above.

lewster · 03-03-2014, 04:34 AM

Re-read #3. There is a lot more to a panel's operational efficiency than crystal type.

For RV use, weight is also an important factor.

Phoenix · 03-03-2014, 01:03 PM

Not sure which type of panel this applies to, but I recall reading that the output from some panels is drastically reduced when only a portion of one panel is in shade. Other types are affected to a significantly lesser extent. Seems like that should be taken into consideration when selecting panels, especially for use on RV roofs not parked in open areas (like the desert southwest).

Airtandem · 03-03-2014, 02:16 PM

Lewster, since you live in both Or. and Fl. which do you use? Do you use, a combination of both?

lewster · 03-03-2014, 07:03 PM

Quote:

Originally Posted by Airtandem

Lewster, since you live in both Or. and Fl. which do you use? Do you use, a combination of both?

AT,

I have 500 watts of mono-crystallin GS-100 panels from AM Solar on the roof of my Sprinter service van (see my avatar), which nicely charge 2 Lifeline GPL-6CT golf cart batteries (300 amp/hours). They run all of my 12VDC loads in the van, interior lighting, Engel AC/DC fridge with Danfoss compressor (runs 24/7/365 for 3 years now) and a Magnum MS-2812 2800 watt pure sine wave inverter.

I currently don't have the charger section of the inverter operational as I have no need to plug in to charge the batteries….the solar does it all! It's a nice, tight operation.

The new GS-130 mono-crystallin panels that we have been using are the same width as the GS-100, just a bit longer to accommodate more cells.

drboyd · 03-03-2014, 08:00 PM

I can readily believe that in the civilized parts of the country, the heat tolerance differential between the two types of panels isn't enough to matter. However, it does get to 117 degrees in AZ with discouraging regularity; when you add in another 35 - 40 degrees of solar insolation effect, the differences could easily be magnified enough to matter.

Attached - picture of my review mirror temperature readout from a couple summers ago.

lewster · 03-03-2014, 08:37 PM

One thing to remember…………….panels should be mounted above the roof to allow air to circulate beneath them for a cooling effect not on the roof like many types of panels do.

drboyd · 03-03-2014, 08:51 PM

How much space do you recommend under the panel?

Quote:

Originally Posted by lewster

One thing to remember…………….panels should be mounted above the roof to allow air to circulate beneath them for a cooling effect not on the roof like many types of panels do.

lewster · 03-04-2014, 04:41 AM

Quote:

Originally Posted by drboyd

How much space do you recommend under the panel?

AM Solar uses proprietary mounting feet that allow you to tilt the panels for a better sun angle. These feet are also adjustable to accommodate for the curvature of Airstream and other RV roofs. I generally mount the panels at least an inch above the roof to allow for sufficient air flow. On curved roofs, one side gets even more space using the highest mounting hole or in extreme cases, a special hi-lift mounting foot to allow the panel to remain flat when traveling.

RickDavis · 03-04-2014, 05:38 AM

I don't think I would be to concerned about slightly reduced output due to heat since heat also usually comes with longer days .
Basically, if the system will do the job with short winter days, summer will not be a problem.
Regarding shading of panels , there are times we have been able to pick up as much as 2 amps just by cranking down the batwing TV antenna.

drboyd · 03-04-2014, 04:12 PM

Quote:

Originally Posted by RickDavis

<snip>
Regarding shading of panels , there are times we have been able to pick up as much as 2 amps just by cranking down the batwing TV antenna.

My TV antenna is in the process of becoming a crank-up rotating dual Yagi wi-fi antenna. I don't know if that will be more shade or less than the old TV antenna was, but it's good to keep in mind!!

timzog · 03-14-2014, 08:11 AM

Renogy also offers a flexible 100w monocrystalline panel for $199 that look promising for an airstream roof install.

http://www.renogy-store.com/100watts.../rng-100db.htm

lewster · 03-14-2014, 10:52 AM

Quote:

Originally Posted by timzog

Renogy also offers a flexible 100w monocrystalline panel for $199 that look promising for an airstream roof install.

http://www.renogy-store.com/100watts.../rng-100db.htm

Interesting..........YES! But not ready for prime time yet. AM Solar has been testing a 2500 watt array of these for the past year in a real world RV situation.

They results are interesting. What they found is that under high heat direct sun situations, the calls cup slightly and retain moisture, capturing dust and leaving a film on the cells.

This has been reducing efficiency by as much as 50%. They are working with the manufacturer on new backing materials to alleviate the problem.

Their meager 5 year warranty should also be a consideration. Stay tuned. They surely have potential !!

BigAl · 03-14-2014, 12:41 PM

I have four flexible panels on my trailer. there is some flexing of the aluminum skin when the sun shines on them but since they are on the curved section of the roof it does not collect moisture that I have seen. Only had them on one season. They don't seem to get any more dirt on them than the rest of the roof. Also the ones I have are amorphous cells and are not supposed to suffer much loss from heat. But they don't have a very high output per square foot.
Al