Ultimate solar panels

[Pete7]

Originally Posted by lifeofreilly57

Where do you plan on cruising? This may also come into play when adding solar. The further from the equator the less efficient panel will be when mounted horizontally.

Its not as bad as you might imagine. Yes the sun is lower in the sky. However, during the summer we have really long daylight hours. In addition the panels are cooler. I have measured 28'c for the glass side of our solar in strong mid day June sunlight. Be interesting to hear what a solar panel in the Carib measures at mid day.

Pete

[Nepidae]

I used 3 Xantrex Max Flex 220W panels (they now have a 330W panel) on our 43 Trawler bridge Hard Top that worked extremely well. Where they were put would not have held the weight you are considering, hence the Flex panels. I had room to add 1 more but didn't see the need before Ian to the top off the bridge.

you mention 28-2900W of power coming from the panels you are selecting but not whether the battery storage will handle that output. Will that be overkill?

We had 6 6V 400aH AGM batteries and the panels seemed well balanced to keep them charged with available sun.

Also, part of the mix is the MPPT you will use to control the setup. I didn't see that mentioned in your post.

The balance of solar generation of the panels and battery storage, coupled with the absorption of the power is important against your daily usage.

Good luck with your project.

[Clamdigger888]

Originally Posted by hezi973

I'm sorry if this was discussed over and over but my quick search didn't yield much. I am thinking ahead toward my future catamaran power management and seeking advice regarding solar. I am planning to have a frame extending from the rear of the main sheet traveler on the cockpit roof extending outward over the dinghy davits. I want big solar to help with big lithium. I am looking for proven efficiency compared to size, weight and longetivity. I visited one or two booths in boat show">Annapolis boat show that were selling solar. Marine dedicated solar is expensive! I am pretty sure most cruiser using hard panels are installing panels that were not necessarily designed for the marine environment. What about bifacial panels? I see them more and more and they couldn't make more sense on a boat. But, from what I see, they are heavy. Weight have a big roll here since I ham hoping to fit 6 x 475+ watt panels on a frame. The weight is adding up...

From what I can see, one of the best panel for the job is Sunpower SPR-MAX6-475COM . It is 475 watt, 50 Lb, 81" x 41" (6 panels: 2850 watt, 300 lb, 138 SF).
One of the best bifacial panel I see is Qcells Q.PEAK DUO XL-G11/BFG. 585 watte, 76 Lb, 95" x 45" (5 panels 2925 watt, 380 lb, 148 SF).

This is internet experience on manufacturers "optimal", not sure how real, conditions. What about real life experience? Any cruiser can share some of his/her experience with panels on a frame? Again, I am looking for top quality, proven hardware but open for anything that make sense. Thank you for sharing!

Hi,
I have a couple off grid setups (none on a boat but am building something small now)
I would recommend a Discovery battery (if you can stomach the cost) I have one of these and it really reliable and charges quickly off a gene.
Real world solar is about 70% of total rating on a sunny day cloudy or rainy it drops a lot.
I’m planning to charge mine when the motor is running off the alternator and have a very small portable array being on the west coast we don’t get much sun for 6-9 months of the year so it makes sense to charge it off the motor if your planning on cruising where there’s better sun you’ll have more power coming in but I would still recommend either a gene or a way to charge off the motor.
I’m not using any components that are “Marine grade “ just keep the inverter and charge controller somewhere dry and warm and away from dust etc dust,soot etc is very hard on the air cooling for the inverter.
Hope this helps

[lestersails]

I vaguely recall guys in some other context sitting around saying "Mine is longer than your's is!"
Boat marketing just a version of that...

[Looking4Neptune]

Last year I put 4 panels on my catamaran, 535 watts each. Something like these DHM-72-10 panels. I am quite happy with them.

Note that you will spend far more (3 to 10 x) for the frame to support, solar controllers and wiring. (I was surprised how much the wires cost...) So my advice is to buy the most wattage for the area, not worrying so much about the cost of the actual panels.

Also, Victron has a 'Solar Calculator' that will help predict the yield from your panels anywhere in the world, month by month. It will also help you choose the right size Victron MPPT for your solar array. Victron is not the cheapest, but I have (mostly) been happy with their products.

Also, panels are getting better all the time. In 3 to 5 years, you may want to replace the panels with more efficient panels. They may not be the same size, so I'd design my initial support frame in a way that could take wider / longer panels later.

I replaced in 2 years and got a 30% increase in power. It was enough to mean that I rarely need to run the generator except when running the watermaker (every few days) or the air con (almost never).

[chrisr]

as i mentioned earlier, imho the solar controller set-up is at least as important as the panels

we have 3 seperate victrons, which ensures that the output of the whole set up is not affected just because one panel is a little shadowed

cheers,

[s/v Jedi]

Originally Posted by chrisr

as i mentioned earlier, imho the solar controller set-up is at least as important as the panels

we have 3 seperate victrons, which ensures that the output of the whole set up is not affected just because one panel is a little shadowed

cheers,

Except that it is. I guess you mean the output of the other panels isn’t affected.

But that isn’t really what is going on. All decent panels have functional bypass diodes that can deal with a partially shaded panel when connected in series at only the cost of the voltage drop over the diode, let’s say 0.6V which becomes insignificant when the array voltage is over 100V and you have multiple strings & diodes in one panel so that other strings that aren’t shaded can still output.

The problem is the MPPT that is different for panels that are oriented different or are in a different position. As one controller only gets to choose a single MPPT point, it is a compromise that works for all connected panels.

A couple good examples:

- 2 or 3 panels on an arch on the stern: connect in series to a single MPPT controller. You can’t beat that.

- 2 panels, one on each side of the boom on top of the bimini: best to have a separate controller for each panel if the oanel voltage is high enough to charge the battery ( must be 5V higher than battery voltage)

[chrisr]

Originally Posted by s/v Jedi

Except that it is. I guess you mean the output of the other panels isn’t affected.

But that isn’t really what is going on. All decent panels have functional bypass diodes that can deal with a partially shaded panel when connected in series at only the cost of the voltage drop over the diode, let’s say 0.6V which becomes insignificant when the array voltage is over 100V and you have multiple strings & diodes in one panel so that other strings that aren’t shaded can still output.

The problem is the MPPT that is different for panels that are oriented different or are in a different position. As one controller only gets to choose a single MPPT point, it is a compromise that works for all connected panels.

A couple good examples:

- 2 or 3 panels on an arch on the stern: connect in series to a single MPPT controller. You can’t beat that.

- 2 panels, one on each side of the boom on top of the bimini: best to have a separate controller for each panel if the oanel voltage is high enough to charge the battery ( must be 5V higher than battery voltage)

thanks for correcting my poor explanation of why multiple controllers are so beneficial

cheers,

[motion30]

I am trying to find two sunpower 435 watt panels To add on to my system. If anybody knows where I can find them I would be appreciative

[Ricky80ss]

I have 5 Q cells Bi-facials, rated 425W, they are wonderful, sometimes going above the 425w rating on ideal conditions. I installed them in 2021. Wondering if 3 years later there are lighter and more efficient panels, any input on this matter will be highly appreciated.

[ekelly36]

Originally Posted by Ricky80ss

I have 5 Q cells Bi-facials, rated 425W, they are wonderful, sometimes going above the 425w rating on ideal conditions. I installed them in 2021. Wondering if 3 years later there are lighter and more efficient panels, any input on this matter will be highly appreciated.

Yeah, Im subbing to this one, im pricing and planning my solar setup..... I know 2 years can make a huge difference in technology....

[Pete7]

Originally Posted by Ricky80ss

I have 5 Q cells Bi-facials, rated 425W, they are wonderful, sometimes going above the 425w rating on ideal conditions. I installed them in 2021. Wondering if 3 years later there are lighter and more efficient panels, any input on this matter will be highly appreciated.

Interesting news on YT and the web suggesting that there is a huge surplus of solar domestic sized panels in Europe and it will likely take 3-4 years to work through. Could well be true because we are seeing some amazing prices for panels at the moment. I guess China can either carry on churning out panels or close the factories, neither great options for them. However, if they knock the Germans and the Taiwanese off the block then they have the market to themselves.

will new better panels come along in the next few years? yes but perhaps small improvements rather than huge increases in efficiency. I chose to fit a pair of 295w panels for now and if something really better comes along, I don't have a problem in replacing them down the line.