solar or generator?

[kthoennes]

Maybe thread drift is the wrong phrase. "Thread coming about, duck your head!" maybe.

 

[Hippocampus]

Returning to solar panels. We’re refitting the boat have a large area of the boat deck dedicated to two large (house size panels). Can’t really tell current production as it’s autumn, cloudy or rainy recently. But do know they’re ~10 years old. Wondering if it’s worth it to replace them while we’re transiently on the hard. Has output increased enough to be worth it? Which brand would you pick for rigid frame panels?

 

[Xlantic]

Returning to solar panels. We’re refitting the boat have a large area of the boat deck dedicated to two large (house size panels). Can’t really tell current production as it’s autumn, cloudy or rainy recently. But do know they’re ~10 years old. Wondering if it’s worth it to replace them while we’re transiently on the hard. Has output increased enough to be worth it? Which brand would you pick for rigid frame panels?

I just got a quote for 445 W panels at €152 each. These are "house panels" approximately 1m x 2m.

Three years ago I bought panels from the same supplier. Those were 320 W (largest available) and cost €190 each.

So, Watts per € have increased by 74% in three years. Not quite Moore's law but close, at least in this example.

 

[socalrider]

I think SunPower still makes the most efficient panels out there, but also among the most expensive. Worth a look - also in 10 years your panels will probably be down from their original rating (0.5-1% per year is the rule of thumb for output degradation).

That said if you've got a list of projects & aren't sure you'll need more production, I'd be inclined to back burner that one assuming the system works - you're probably looking at a ~25-35% increase by going back to new, which may or may not move the needle on boat enjoyment. If it ain't broke...

 

[mvweebles]

Returning to solar panels. We’re refitting the boat have a large area of the boat deck dedicated to two large (house size panels). Can’t really tell current production as it’s autumn, cloudy or rainy recently. But do know they’re ~10 years old. Wondering if it’s worth it to replace them while we’re transiently on the hard. Has output increased enough to be worth it? Which brand would you pick for rigid frame panels?

Solar panels degrade over time - those panels are likely in the 85%-90% of original efficiency. Plus there are better panels now than even a few years ago. The best panels were SunPower (now Maxeon).

If I can suggest, if you are looking to replace 10-year old panels, you may want to look at the controller too. 10-years ago, MPPT were not common and are an improvement over older PWM controllers. Sizing the voltage/amp components isn't tremendously complex, but I'd ping a new thread with specifics including wire-run lengths, pictures, any concerns about shading (or if the panels are on an arched top), etc.. Best solar input I've gotten has been on CruisersForum, though there are some decent solar folks on this forum too.

Good luck -

Peter

 

[sbman]

Returning to solar panels. We’re refitting the boat have a large area of the boat deck dedicated to two large (house size panels). Can’t really tell current production as it’s autumn, cloudy or rainy recently. But do know they’re ~10 years old. Wondering if it’s worth it to replace them while we’re transiently on the hard. Has output increased enough to be worth it? Which brand would you pick for rigid frame panels?

10 years ago, residential panels averaged about 200 watts each. There are now many options ~400 watts in the same size (3'x6'). I have three such residential sized panels on my boat at 385W each. Newer panels are probably also better in low light situations. My 1155 rated watts of panels put out 250-300 watts of power on a overcast day, and are hitting 800+ on sunny days (flat mounted, autumn). Rain clouds bring it to nothing but that rarely happens here.

If your panels are down near the 200W spec, You could potentially double the output of the system in the same physical space, if your older panels are closer to 300W it might not be worth the effort. You might also need a new controller to deal with higher output panels.

 

[Andy G]

How did we segue from "Solar or generator" to state sales tax rules? :confused:

An excellent example of soft power diplomacy.

 

[BruceK]

How did we segue from "Solar or generator" to state sales tax rules?

Rats, I was just getting interested in changing my name to "Fluffy Vanderbilt"..all those millions....

 

[rslifkin]

10 years ago, residential panels averaged about 200 watts each. There are now many options ~400 watts in the same size (3'x6'). I have three such residential sized panels on my boat at 385W each. Newer panels are probably also better in low light situations. My 1155 rated watts of panels put out 250-300 watts of power on a overcast day, and are hitting 800+ on sunny days (flat mounted, autumn). Rain clouds bring it to nothing but that rarely happens here.

If your panels are down near the 200W spec, You could potentially double the output of the system in the same physical space, if your older panels are closer to 300W it might not be worth the effort. You might also need a new controller to deal with higher output panels.

Agreed, new panels will likely be a good bit higher output. As far as real world output, on a good, sunny day, I've seen my 2x 410W panels (made by Trina Solar) sustain output in the high 700s and I've seen peaks of just over the 820w rating.



I've also seen total daily production of 3.7 kwh more than once, and that's with the panels not being at full output for a couple of hours later in the afternoon due to full batteries and not enough load to get the full available output. So 4 kwh or a little more is possible on a good day from 820w of panels, although I wouldn't count on getting that much (any less than perfect day will give less, but somewhere in the 3.2 kwh range is pretty easy to get provided it's not solid overcast or rainy).

 

[Hippocampus]

Thanks guys. Due to aesthetic considerations downsized the pilot house screen from 16” to 12”. Without a large amount of carpentry the 16” wouldn’t fit so have a couple of boat bucks to play with. Will look into SunPower and others as well as new controllers. Had Kyocera on last boat and was well pleased with them.

 

[rslifkin]

Thanks guys. Due to aesthetic considerations downsized the pilot house screen from 16” to 12”. Without a large amount of carpentry the 16” wouldn’t fit so have a couple of boat bucks to play with. Will look into SunPower and others as well as new controllers. Had Kyocera on last boat and was well pleased with them.

Personally, I'd skip the SunPower panels unless you need the maximum wattage in a given space and cost is no object. When I priced them out, a single 400w Sunpower panel was smaller than the 410w ones I bought, but the price of 1 (not including shipping) was more than I paid for 2 panels plus truck freight.

The panels I've got are the 410w version of this (just over $200 each): https://static.trinasolar.com/sites/default/files/Datasheet_TallmaxM_DE15H(II)_NA_2020_RD_B.pdf

A few extra $$$ will get you into 420 - 440w panels at this point.

 

[mvweebles]

I think a better question is where to purchase larger panels. Last set I bought was for a friend's off-grid cabin a couple years ago; and the 4x200w square panels I put on my boat. Now, everything seems skewed towards 12v (nominal) systems. I recently installed 2x160w on my camper van - Newpowa which are Vietnamese built, likely shifted from China due to US tariffs. They are fine panels but I'm not sure how you tell one way or the other unless they delaminate too soon.

Over the years, I have heard good things about Kyocera too. But things change so quickly in solar - Siemens used to be a good brand. They likely still produce for industrial solar farms, but I haven't seen them in smaller residential setups for a while.

Please update - always interested in latest/greatest thinking.

Peter

 

[rslifkin]

I think a better question is where to purchase larger panels. Last set I bought was for a friend's off-grid cabin a couple years ago; and the 4x200w square panels I put on my boat. Now, everything seems skewed towards 12v (nominal) systems. I recently installed 2x160w on my camper van - Newpowa which are Vietnamese built, likely shifted from China due to US tariffs. They are fine panels but I'm not sure how you tell one way or the other unless they delaminate too soon.

Over the years, I have heard good things about Kyocera too. But things change so quickly in solar - Siemens used to be a good brand. They likely still produce for industrial solar farms, but I haven't seen them in smaller residential setups for a while.

Please update - always interested in latest/greatest thinking.

Peter

If you look for marine or off-grid panels, you find the small 12/24v stuff. If you look for panels intended for grid-tied house applications, you get the big ones. Mine came from these guys: https://www.solaris-shop.com/

 

[sbman]

I've purchased from Santan solar. They have warehouses in Phoenix, AZ and Savannah GA. If you are able to pick the panels up from one of their locations, you can get refurbs, used, and surplus panels at significant savings. If you need panels shipped, the shipping costs become a significant factor.

https://santansolar.com/

The panels I purchased were refurbished commercial panels at a significant savings, $100 each for 385W Jinko panels. The panels were pulled from a commercial installation due to defective bypass diodes, Santan replaced the diode packs on them bringing them back to full output, they are about 3 year old panels. Unfortunately, they are now out of stock on those specific panels but they have a variety of options from time to time. They also sell new panels.

 

[firehoser75]

Thanks guys. Due to aesthetic considerations downsized the pilot house screen from 16” to 12”. Without a large amount of carpentry the 16” wouldn’t fit so have a couple of boat bucks to play with. Will look into SunPower and others as well as new controllers. Had Kyocera on last boat and was well pleased with them.

On my NT 37, I installed 2 panels on the pilothouse roof without drilling any holes. I constructed a support framework of SS tubing, and the midpoint support is only held in place by the system weight and some Sikaflex 291. No issues with movement or any others as well. They were rated (total) at 570 watts. With solar more is better (space allowing) as most days they more than met our electrical needs, but on very cloudy rainy days they definitely fell short. Definitely use a good MPPT controller to maximize your amperage input.

Good luck with your new NT 42.

 

[GoneDiving]

I think a better question is where to purchase larger panels.

Another question is if the largest panels use most of the space available. I increased the total area of panels and therefore out put by using more smaller 250W panels vs less of the largest available.

Boats tend to be more confined by total area available and have these areas in smaller weird shapes than houses.

 

[GoneDiving]

On my NT 37, I installed 2 panels on the pilothouse roof without drilling any holes. I constructed a support framework of SS tubing, and the midpoint support is only held in place by the system weight and some Sikaflex 291. No issues with movement or any others as well.

+1. My Previous Owner installed panels by simply bonding 50*25mm lengths of aluminium to the roof then bolting the panels direct to these rails.

These went no where, even in conditions that saw many surrounding vessels loose their panels or support structures. I'm doing the same with a larger grid, just running the aluminium the length or the vessel vs awarthship to prevent water pooling.

 

[rslifkin]

+1. My Previous Owner installed panels by simply bonding 50*25mm lengths of aluminium to the roof then bolting the panels direct to these rails.

These went no where, even in conditions that saw many surrounding vessels loose their panels or support structures. I'm doing the same with a larger grid, just running the aluminium the length or the vessel vs awarthship to prevent water pooling.

I mounted mine similarly. I glued 2" x 3" pieces of aluminum angle to the deck with 4000UV. Then bolted another piece of angle to that with the panel bolted to the top (to make a 2 piece C bracket). Each panel has 4 of those mounts on it. So far, they've worked out fine and nothing has moved at all. Worst winds they've seen were about 40 kts. And whatever they saw when we ran through the middle of a rather windy thunderstorm in confused 3 - 4 foot seas.

 

[Hippocampus]

Great input. Please keep it coming. Been thinking of mounting panels on a SS or Al pipe framing a few feet off the boat house deck. That would allow space under them for storage of light stuff (fenders, paddle boards and such). Concern is whether although horizontal they would have troubles in high winds. Our dinghy is on a Freedom Lift so don’t need the boat deck. Thoughts?

 

[rslifkin]

Great input. Please keep it coming. Been thinking of mounting panels on a SS or Al pipe framing a few feet off the boat house deck. That would allow space under them for storage of light stuff (fenders, paddle boards and such). Concern is whether although horizontal they would have troubles in high winds. Our dinghy is on a Freedom Lift so don’t need the boat deck. Thoughts?

For my panels, the mounts follow the deck camber, so the panels are angled slightly forward and slightly out to the sides. This helps self cleaning, plus it means wind load is almost always slightly downward (only exception might be if I'm up on plane, trimmed up a bit and running into a strong headwind).

Mounting them up higher would probably require beefier mounts than having them close to the deck (mine are 2" off the deck), but it's certainly possible to do. Think about panels on an arch on a sailboat.

 

[Xlantic]

Great input. Please keep it coming. Been thinking of mounting panels on a SS or Al pipe framing a few feet off the boat house deck. That would allow space under them for storage of light stuff (fenders, paddle boards and such). Concern is whether although horizontal they would have troubles in high winds. Our dinghy is on a Freedom Lift so don’t need the boat deck. Thoughts?

The panels themselves should have no problem with strong winds. My panels often face sustained 100 km per hour winds over the winter. It is, as mentioned, the mounts to the panels the structure that has to be sturdier.

In particular you want to avoid vibration in strong winds that could lead metal fatigue. As such the mounted panels should not be "springy".

 

[mvweebles]

Great input. Please keep it coming. Been thinking of mounting panels on a SS or Al pipe framing a few feet off the boat house deck. That would allow space under them for storage of light stuff (fenders, paddle boards and such). Concern is whether although horizontal they would have troubles in high winds. Our dinghy is on a Freedom Lift so don’t need the boat deck. Thoughts?

Great idea - always a hassle finding a decent place for fenders. I don't think it would take much structure to support the panels. You could have brackets fabricated to stow paddleboards upright along the support legs. Windage would increase, but only marginally compared to having a dingy on the boat deck.

Good luck!

Peter

 

[JDCAVE]

I mounted mine similarly. I glued 2" x 3" pieces of aluminum angle to the deck with 4000UV. Then bolted another piece of angle to that with the panel bolted to the top (to make a 2 piece C bracket). Each panel has 4 of those mounts on it. So far, they've worked out fine and nothing has moved at all. Worst winds they've seen were about 40 kts. And whatever they saw when we ran through the middle of a rather windy thunderstorm in confused 3 - 4 foot seas.

That’s what I did. No need to bolt into the roof. I used 4200. I would have liked 500 watts of panels but had to settle on 435 watts. These have worked well. I give the batteries a bump in the morning with the Genny and then the solar brings them up to float by the end of the day.

Jim

 

[koliver]

For another take on mountings, see https://www.trawlerforum.com/forums/s31/my-new-solar-system-44588.html

Now after final fitting of the SS supports, the wing supports have proven themselves. The panels stand off the upper deck rails to extend past the lower rails, but when rafting, are still within the perimeter defined by the fenders below.
I no longer need to plug in at outstations, as the input from the solar system exceeds my usage in the sunny months, when I have a fridge and a freezer both operating, and in the shoulder season when there is little sun and the freezer and fridge are rarely used. This month in particular has been unusually dark and yesterday the batteries were at over 13v. Plugged in, I rarely, if ever, saw battery voltage that high.

 

[Marco Flamingo]

I attached a flexible solar panel using male SNADs on the pilot house roof. The panel is on the top of a trailerable boat, so I know that it can take +70 mph winds. The panel had grommets around the edges, through which I attached female stainless snaps using tiny stainless bolts and nylok nuts. Each flexible panel also needs something in the middle to keep it from touching the deck surface. The shortcoming of flexible panels laid directly on the deck is that temperatures behind the panel can rise and reduce the efficiency. The 3/4 inch stand-off air space provided by the SNADs seemed to do the trick. I've never tried to remove a SNAD after attaching to a gel coat surface and imagine that it might be a chore.

 

[Nomad Willy]

Neither ..
We went trawlering for 15 years and didn’t feel the need.
Baugh humbug
HaHa

 

[Marco Flamingo]

I found a picture (worth 1,000 words) of the SNAD use for the installation of a flexible solar panel. The surface was curved and I wanted to keep a low profile with a minumum of hardware.

 

[GoneDiving]

I found a picture (worth 1,000 words) of the SNAD use for the installation of a flexible solar panel. The surface was curved and I wanted to keep a low profile with a minumum of hardware.

A very neat install but I'd be worried about the small glue area and it's holding power in a gale. Do they have a load rating?

 

[Marco Flamingo]

"Strong Gale" is only 50 mph. Since this boat is on a trailor, I've probably done the equivilant of 100 mph going into headwinds on the freeway. I have only 4 SNADs holding down my small panel (50W). I'd use more on larger panels, maybe one every two feet. Flexible panels follow the contours of the deck, offset only by the height of the SNAD, and there just isn't that much for the wind to get ahold of.

 

[BruceK]

+1. My Previous Owner installed panels by simply bonding 50*25mm lengths of aluminium to the roof then bolting the panels direct to these rails.

These went no where, even in conditions that saw many surrounding vessels loose their panels or support structures. I'm doing the same with a larger grid, just running the aluminium the length or the vessel vs awarthship to prevent water pooling.

On my previous boat I sikaflexed 1" square teak lengths to the FB, screwed right angle aluminum strip to the panel sides, and screwed the other side to the teak strips. Achieving 1" clearance for the panels and no penetration of the FB deck. All stayed in place.