Solar Power Performance

[Dcsqatar]

Over the last two seasons, I have taken measurements of my Solar Cell performance on my 2 year old 29S with standard (as supplied) solar panel. On a sunny day in August here in the PNW, my solar cell puts out a max of about 8.2A at 21.5v. It will stay at 6 - 8A for about 6 hours (say 10:30 - 16:30). No marked deterioration in performance this vs. last year. Does that sound about right?

 

[Martin610]

Sounds about right, but we would need to know the wattage of your particular panel.

I have a 2013 C-28 with the 140 watt panel. I get a little less amperage out of it than you are getting. Considering age of the panel and the wattage I think mine is producing correctly.

An upgrade is on the planning list for me next winter.

 

[GaylesFaerie]

A rough estimate of the correct wattage for your latitude I believe will be about one fourth the wattage of the panel. So a 100W panel may yield you 25a. Another critical factor is shading. If you panel is even small partially shaded the performance drop is significant. GF

 

[Dcsqatar]

Thanks for the replies. I checked and the panel supplied with my boat is 140W. Assuming the solar panel controller is accurate, it consistently produces between 21 - 22v. Assuming 21.5v, the maximum amps would be 6.5A based on Power = voltage x current. If so, maybe I should be happy with my system reporting 8 - 8.5A at peak NW sun.

Are there upgrades that have a higher power density (i.e., will produce more power with same or similar size)? I have other stuff on my roof and therefore not a lot more room for a larger solar panel.

 

[Submariner]

Thanks for the replies. I checked and the panel supplied with my boat is 140W. Assuming the solar panel controller is accurate, it consistently produces between 21 - 22v. Assuming 21.5v, the maximum amps would be 6.5A based on Power = voltage x current. If so, maybe I should be happy with my system reporting 8 - 8.5A at peak NW sun.

Are there upgrades that have a higher power density (i.e., will produce more power with same or similar size)? I have other stuff on my roof and therefore not a lot more room for a larger solar panel.

The issue with solar on a boat is space. Solar panels are made in various shapes, sizes, and efficiencies. The average effeciency panels are around 12-16% efficient. The highest efficiency panels are around 24%.

In general, for boating in the Pacific Northwest, 140 watt panel will produce about 35-45 amps a day. Upgrading to a more efficient panel will get more watts in less space. But it also will come down to the space you have available to mount them.

I chose to only use my roof rack for solar because power was most important to us. I put up 2 x 200 watts (400 watts total) and I see anywhere from 1800 to 2700 watts a day. (about 150 amps a day). This meets our electrical needs so much that we rarely require shore power hookups at a guest marina.

The 200 watt panel I went with are the same width as the factory 160 watt panel and are 3 inches shorter. 40 more watts and 3 inches less in length because they are 23.7% efficient.

 

[Kimberly Dawn]

I have recently discussed solar panels with RT for our pending R29S. I won't try to address the hardware specs or system performance of RT solar systems, but defer to more knowledgeable individuals to jump in and do so.

I can say RT said they're switching from a polycrystalline panel to a monocrystalline panel, and increasing the wattage from 160 to 190 watts; the monocrystalline panel is more tolerant of partial shading. I opted to upgrade to a 270w monocrystalline panel with an upgraded controller.

Bob
The Doghouse 2

 

[Scottfree]

My R29 Classic had real weight issue on the stern. I wanted to get rid of my seldom used generator and level the boats port list. I decided on a solar system. Im a fan of bigger being better. I pulled out my MASE generator and moved my house batteries from the port side to the starboard side. I installed two 370 watt monocrystalline panels, a Victron 150/60 controller and a Victron BMV-712 Smart monitor. Both the controller and monitor are bluetooth so can be monitored by a smart phone. Not that its to far to walk to the gauge but they came with the bluetooth. I am currently using the 3 year old group 31 deep cycle batteries. The batteries will be replaced but Im cheap and am researching batteries to death! The performance is beyond amazing. I run the Nova cool fridge, a beer cooler and a small chest freezer 24/7. We run the invertor for coffee, toaster and microwave and yes even a hair dryer. During the day with sunlight you can not get ahead of the solar. We have the Yanmar 6BY with a 150 amp Alternator that would not run the main AC under way. With the solar during a sunny day while under way we ran the AC for 4 hours straight. The panels were pulling over 600 watts. I do not have enough battery to run AC at anchor. I'm into the system for about $3,000 CDN which I think is about $129 USD (Not good at math!)

Lithium batteries would be super cool but the wife might notice those on the visa!

Cheers, Leon

 

[Wee Venture]

I opted to upgrade to a 270w monocrystalline panel with an upgraded controller.

Bob
The Doghouse 2

Bob, which panel did you go with? I am interested in upgrading also.

John

 

[Kimberly Dawn]

I'm going with Custom Marine Products panel and an Epever DuoRacer 30 amp controller.

Bob

 

[Submariner]

I'm going with Custom Marine Products panel and an Epever DuoRacer 30 amp controller.

Bob

The panels I bought were Custom Marine Products, Mono panels. That 270 watt panel, and that DuoRacer controller (which is an MPPT solar controller), should work out great for you.