High efficiency SOLARA panels?

[GeorgeB]

Thinking upgrading my solar panels to more efficient ones so I could make room for a bathroom skylight. Found those SOLARA panels from Germany available in the US through Coastal Climate Control.

Rigid high efficiency marine panels

https://www.youtube.com/watch?v=xThHpRvPJJ8

Flexible walk-on marine panels

https://www.youtube.com/watch?v=9VgG...ature=youtu.be

The whole array of panels and the new EZ mount for the light ones.

https://www.youtube.com/watch?v=aPTk2Faod4I

Theoretically you can get the same solar gain by using less panels but more efficient ones. I now have 4 : 41" x 21" that total 380W. I could install 3 wider 22" x 59" 140W (S565M44) panels and have a higher 420 W total output.

SOLARA panels on the Coastal Climate Control web site
https://www.coastalclimatecontrol.co...ar/solara.html

The rigid 140 W high-grade panel
https://www.coastalclimatecontrol.co...lar-panel.html

Do you know any other high efficiency solar panels available on the market?

Photo of my actual solar set-up:

[booster]

If I did the calcs correctly, both the panels you list with the wattages and sizes have the same efficiency. The gain you would get would be from more efficient placement on the roof.

Those efficiencies are pretty common I think. Our 4 year old Grape solar panels are 20X40 IIRC and 100 watts, so right in the same area, or even a bit better.

[mojoman]

Upgrading the solar controller to a MPPT if you are running a lessor type may be a better choice.

[GeorgeB]

Originally Posted by booster

If I did the calcs correctly, both the panels you list with the wattages and sizes have the same efficiency. The gain you would get would be from more efficient placement on the roof.

Those efficiencies are pretty common I think. Our 4 year old Grape solar panels are 20X40 IIRC and 100 watts, so right in the same area, or even a bit better.

Thanks for answering my question booster. When you mean both panels have the same efficiency, you mean the rigid and flexible ones from Solara or when you compare them with mine.

Mine are 90W (21'x41") and Solara are 140W (22" x 59"). My primary goal is having a wider panel area so I can take out one panel to accommodate for a skylight/vent for the bathroom but it would be nice if I can find more efficient ones. Not sure I'm willing to spend that much more money to gain a couple percentage.

I understand that the 140W are bigger but are there other important data to consider when evaluating efficiency of a panel like this?

On the S565M44 panel page: https://www.coastalclimatecontrol.co...lar-panel.html

140 watts Peak Power at STC*
25.1 volts Peak Power Volts
5.58 amps Peak Power Amps
565 watt/hrs Est. Daily Yield (summer)**
22.5% Cell Efficiency*
59" Length
22" Width
1" Thickness
21.2 lb Weight
Offers the best low-light behavior - grabs current even when the sun is low.
Genuine SunPower® monocrystalline back-contact solar cells. These are the real deal, not the back-contact solar cells made available to the secondary market that don't (and shouldn't) carry the prestigous SunPower name.
These panels have a long lifetime, even under extreme conditions with scratch-resistant, thermally hardened, non-glare, thin glass and excellent mechanical load resistance thanks to a torsion-resistant module frame.

[booster]

I just compared what you have to the larger 140 watt panel with the efficiency calculated in watts per square inch of panel.

The data shows 22.5% cell efficiency, and I don't know how or if that relates to panel efficiency. Ours are rated at 18% cell efficiency but seem to be about the same at calculated panel efficiency. Hopefully someone is up better on the spec details. They all make lots of claims about low light capability, also, and I don't know if there is any real spec on that.

Those are some pretty expensive panels, though. At 25 volts for max power point, you would certainly want an MPPT controller to get the most out of them.

[GeorgeB]

Originally Posted by booster

I just compared what you have to the larger 140 watt panel with the efficiency calculated in watts per square inch of panel.

The data shows 22.5% cell efficiency, and I don't know how or if that relates to panel efficiency. Ours are rated at 18% cell efficiency but seem to be about the same at calculated panel efficiency. Hopefully someone is up better on the spec details. They all make lots of claims about low light capability, also, and I don't know if there is any real spec on that.

Those are some pretty expensive panels, though. At 25 volts for max power point, you would certainly want an MPPT controller to get the most out of them.

Expensive indeed! I guess they are other less expensive 140/120W 59" panels available. A 60" x 66" (3 panels) area seems like an ideal width for a replacement on my roof, compared to the actual 41" x 84" (4 panels). It would leave 18" roof space for a skylight (close to the actual Fantastic vent).

Where's the best place/web site to look for buying solar panels for RVs?

.

[mojoman]

It is based on size vs watts. So a higher efficiency panel will be slightly smaller. I managed to mount 440 watts on my roof plus an AC,vent,antennas on a 19.5' van. They are the cheaper Costco grape solar panels. Max amps I ever got out of them was 29 amps so far.

[GeorgeB]

Originally Posted by mojoman

It is based on size vs watts. So a higher efficiency panel will be slightly smaller. I managed to mount 440 watts on my roof plus an AC,vent,antennas on a 19.5' van. They are the cheaper Costco grape solar panels. Max amps I ever got out of them was 29 amps so far.

440W solar array. Impressive! Do you have a photo of your roof set-up?

29 amps is not bad.
I recorded a maximum 18.4 amps gain from my 380W panels but my batteries are never very low. I also suspect my solar controller is not very efficient and adjusted to a conservative GEL setting.

[mojoman]

IMG_7920_zpsjctaokcu.jpg Photo by mcgiotes | Photobucket
I added an additional 40 watt panel to the left of the AC after this photo was taken.

[mojoman]

You would problably benefit from a MTTP controller, mine are two in parallel then in series so the controller sees 28v.

[GeorgeB]

Originally Posted by mojoman

IMG_7920_zpsjctaokcu.jpg Photo by mcgiotes | Photobucket
I added an additional 40 watt panel to the left of the AC after this photo was taken.

Impressive build! I never took the time to look at all the mods you did on the van. Nice job!

More questions regarding electrical systems:

Which MTTP controller did you installed? The way you wired the panels, I guess the higher voltage prevents loosing current or/and making the controller more efficient?

My upfitter wired the output of the controller to the battery (too long wires IMO) but also directly to the main fuse board. I had a master switch installed (on the positive of the battery bank) but I have to take the fuse of the sensing wire of the controller out to shut off the solar (because of that direct link between the controller and the main fuse board) Never saw a circuit wired like that. I know from this forum that directly wiring the solar to the system without a battery is bad, but I never leave the system on without a battery. My concern is toward the efficiency of a double solar input: to the battery and to the main circuit.

[mojoman]

MidNite Solar Kid 30a MPPT- White - MNKID-W Charge Controller - Wholesale Solar
The controller is only rated to 30 amps which is less than the rated max output of the solar panels. I figured I would never see more than 30 amps out of them due to dirt, alignment, etc..
Solar folks recommended that set up 2S2P for max efficiency of the MPPT controller on an RV. I ran #6 cable to the controller from the panels and to the batteries.

I wired a 40amp circuit breaker between the controller and the solar panels and a 30 Amp just before connecting to the battery. The controller I have has a 30 amp fuse in it which I replaced with a mini breaker.

Your Upfitter did not install for maximum performance. If its a very long run to the battery, I would run #4 wire to the battery so you can utilize more of the free power. I generally go 1-2 sizes heavier in wire gauge than recommended.

[GeorgeB]

Originally Posted by mojoman

MidNite Solar Kid 30a MPPT- White - MNKID-W Charge Controller - Wholesale Solar
The controller is only rated to 30 amps which is less than the rated max output of the solar panels. I figured I would never see more than 30 amps out of them due to dirt, alignment, etc..
Solar folks recommended that set up 2S2P for max efficiency of the MPPT controller on an RV. I ran #6 cable to the controller from the panels and to the batteries.

I wired a 40amp circuit breaker between the controller and the solar panels and a 30 Amp just before connecting to the battery. The controller I have has a 30 amp fuse in it which I replaced with a mini breaker.

Your Upfitter did not install for maximum performance. If its a very long run to the battery, I would run #4 wire to the battery so you can utilize more of the free power. I generally go 1-2 sizes heavier in wire gauge than recommended.

Thanks for all the info.

[ra2jim]

Originally Posted by GeorgeB

Expensive indeed! I guess they are other less expensive 140/120W 59" panels available. A 60" x 66" (3 panels) area seems like an ideal width for a replacement on my roof, compared to the actual 41" x 84" (4 panels). It would leave 18" roof space for a skylight (close to the actual Fantastic vent).

Where's the best place/web site to look for buying solar panels for RVs?

.

Here's a website for solar panels in general: Solar Panels from Wholesale Solar. I've heard they're helpful with DIY folks like you. They have a small area in that site for RVs, but I think they can customize for you. Good Luck!
Jim

[GeorgeB]

Originally Posted by ra2jim

Here's a website for solar panels in general: Solar Panels from Wholesale Solar. I've heard they're helpful with DIY folks like you. They have a small area in that site for RVs, but I think they can customize for you. Good Luck!
Jim

Thanks Jim! I'll keep you posted.