Solar Panel Recommendations - Summer 2020

jviss

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Feb 5, 2004
6,745
Tartan 3800 20 Westport, MA
I want to add solar to my Tartan 3800. I have two times about 55x21" available on the bimini. I have seen "cheap Chinese" flexible panels of 120W each that will fit. They are inexpensive, but get mixed reviews.

Are there any "quality," "brand name" panels available?

Also, want and MPPT controller recommendation. Similarly, there are literally $13 ones on eBay, and also $300+ ones from Morningstar, et.al. Would appreciate a recommendation on these, too.

Thanks,

jv
 
Jan 11, 2014
11,323
Sabre 362 113 Fair Haven, NY
One has to wonder about quality issues.

This Solara Flexible 110 panel with SunPower cells sells for about $1K.

This comparable SunPower flexible Panel sell for about a quarter of the price at $225 and alleges uses the same SunPower cells.

While it would be normal to have some price variations, this seems a bit large. One possibility is the quality and efficiency of the cells. Silicon wafers from different parts of the same crystal may have subtly different qualities yielding differences in performance. While they cells may come from the same company, Sun Power, the cells may not be equal.

Another possibility is the quality of the construction of the panel itself, does one have a more durable construction than the other?

An example of you get what you pay for, Solbian makes 2 grades of flexible panels. One uses Sunpower Monocrystalline cells and retails for about $1K while another using less efficient cells has a list price of about half that, but it uses less efficient polycrystalline cells.

 

Rick

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Oct 5, 2004
1,095
Hunter 420 Passage San Diego
One thing to consider in the flex panels is percent of efficiency. I have these and they are 23.5 percent efficient. I have four of them for under $500. When I get the best sun, they usually are generating 16 to 20 amps. They are three years old. As far as controllers, I use and like the Epever brand. I have two, a 30 MPPT, and a 40MPPT because I also have a 175W panel on my davits and you can not tie unlike panels to the same controller. Sure there is higher end stuff out there, but the Epever has a USER function, and that allows me to program it for my lithium batts.
Below is the links.

 
Feb 26, 2004
22,760
Catalina 34 224 Maple Bay, BC, Canada
Sep 25, 2008
957
Macgregor & Island Packet VENTURE 25 & IP-38 NORTH EAST, MD
Solbian panels are the most efficient, lightest and naturally the most expensive. SunPower panels uses the good cells and are a good value. Victron makes MPPT controllers in many sizes. The newer ones have Bluetooth and can send your panel info to your phone if you have the app installed. Their solar and battery monitors are all plug ins to one another. Their products are of high quality. Take a look at their website, very informative.
 
Apr 8, 2011
768
Hunter 40 Deale, MD
I looked hard at flexible solar panels of many brands and didn't want to spend premium prices. I tried to strike a balance between quality and price, and found that Renogy had decently reviewed panels at a mid-price point, but most importantly they have a really good warranty - which the cheap panels do NOT. I bought their 160 watt panel and mounted it on my Bimini, and it performs well. Its not a miracle worker, but I've gotten 710 wh of power out of it in a really good day, and its now in its second season. If you go that route a couple of recommendations:

1. Buy directly from Renogy - not Amazon, etc. They have sales frequently (there's one on right now), you're getting fresh stock - not something from a year ago in a warehouse, and if there's a warranty issue you work with them directly.

2. I have noticed some white spots on my panel at the end of the first year. I talked with Renogy and sent them photos and they had me run a test on the panel whose results indicate they don't seem to have affected the output - yet. But they assured me it was covered under warranty if it became a problem.

3. If mounting on a Bimini consider having your canvas shop do a custom install for you. It will look much neater, and be much more secure that way. They do a lot of them, so its pretty routine.

I just assume with a flexible panel - even mounted on top of the Bimini out of the way - that I'll get 5 years out of it and probably have to replace a mid-priced panel. It was $299 on sale - and right now its 15% off. The warranty on the panel on their website is:

25-year power output warranty: 5 year/95% efficiency rate, 10 year/90% efficiency rate, 25-year/80% efficiency rate
5-year material and workmanship warranty

If they're willing to stand behind it, I was willing to take a chance on it. So far its worked out well. Their 100 watt panels might fit your space. One thing I found was that you're somewhat limited by the panels that will actually fit your useful space, so you may have to look around to find the best fit from a manufacturer.

Good luck.
 
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Feb 26, 2004
22,760
Catalina 34 224 Maple Bay, BC, Canada
My read is that flex panels mounted right on top of bimini cloth is not a good idea because of heat buildup.

Research whatever options you select, up the gazoo. :) I know you will. :biggrin:
 
Jan 11, 2014
11,323
Sabre 362 113 Fair Haven, NY
My read is that flex panels mounted right on top of bimini cloth is not a good idea because of heat buildup.

Research whatever options you select, up the gazoo. :) I know you will. :biggrin:
That is my understanding too. Up north it will be less of a problem, however, going south it may be more of an issue. When panels get warm their efficiency goes down.

And while flexible panels will flex, they are not designed to be repeatedly flexed. They will conform to gentle curves but they need to be properly supported.
 
Nov 21, 2007
631
Beneteau Oceanis 34 Kingston, WA
I ended up ordering this kit from eMarine Systems in Florida. It's two SunPower 110W panels, a Victron controller, 40' of cable, and a circuit breaker. I couldn't find the individual components for less anywhere else, even though I had to pay shipping. The specs indicate that these may be too wide for you. I was also very tight on space on my bimini. I thought that they would be almost an inch too long, on both sides. Ultimately, I decided to pull the trigger on the purchase, and having received them and laid them out on my bimini, I think they will fit perfectly. The kit came with the controller that I wanted, and I thought that even if the panels didn't fit, I might be able to sell them for enough to break even if I had to keep searching for different flexible panels.
 
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Apr 8, 2011
768
Hunter 40 Deale, MD
That is my understanding too. Up north it will be less of a problem, however, going south it may be more of an issue. When panels get warm their efficiency goes down.

And while flexible panels will flex, they are not designed to be repeatedly flexed. They will conform to gentle curves but they need to be properly supported.
Mounted on top of a Bimini that is properly stretched tight there's almost no flex - certainly WAY less than today's panels are designed to endure for long periods of time. My canvas shop provided backing to add stiffness, which is sandwiched between the back of the panel and the canvas, so there's virtually no flex at all. And while the physics of heat do have an effect on all solar panels, there's sufficient airflow under and over the canvas that its never been an issue for me in the VA/MD area, even at the height of summer. I can't say I've made an effort to measure any production loss based on temperature, but I can say it hasn't been noticeable in any practical sense.
 
Jan 11, 2014
11,323
Sabre 362 113 Fair Haven, NY
Mounted on top of a Bimini that is properly stretched tight there's almost no flex - certainly WAY less than today's panels are designed to endure for long periods of time.
This is key. Many flexible panels are designed to accommodate the camber on a hard dodger or deck and not flopping around strapped to a boom or loosely fitting Bimini or dodger.
 

Bob S

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Sep 27, 2007
1,771
Beneteau 393 New Bedford, MA
I bought the 100W version last off season from Arizona Wind & Power. I am/was mounting them on the bimini but my canvas guy was shut down and I'm not sure my new Bimini will be ready for this season. I planned on mounting the SunPower panels with 3/16 plastic corrugated sheet to reduce the flex.
 
Jul 1, 2010
962
Catalina 350 Lake Huron
I've used Victron controllers on the 3 solar installs I've done, 2 on boats and one on an off-grid cabin. They are high quality, programmable for different battery types and work great.

I have 420 watts of Renogy flexible panels on the boat I'm sitting in right now. So far so good. This is the 2nd season with them. I did beef up the bimini to support them better over the stainless center arch by installing 3 battens per side under the fabric and over the the arch. Pockets added to the bimini hold the battens in place. I also replaced the bimini straps with stainless struts. The panels are attached to the fabric with 3M Dual lock.

The cabin has 960 watts of Renogy rigid panels on a storage shed roof to power it.
 
Jan 4, 2010
1,037
Farr 30 San Francisco
So the temperature dependency of the sunpower panels is -.35% per degree C. So output will drop about 10% by the time they are too hot to touch. I would bet the flexible panels shed heat better than the conventional panels.
 
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Jan 11, 2014
11,323
Sabre 362 113 Fair Haven, NY
So the temperature dependency of the sunpower panels is -.35% per degree C. So output will drop about 10% by the time they are too hot to touch. I would bet the flexible panels shed heat better than the conventional panels.
When the panel is attached to a Bimini there is no airflow under it to help cool the panel. Same, if the panel is mounted directly to a cabin top or hard dodger.