Solar Panels on small boat

[DangerousPirate]

Hello, I have a very powerhungry little boat due to Laptop, Phone and Tablet usage. So I thought about independet energy solutions like solar panels.

What is a cheap way to put up two 100w solar panels that is adjustable so I can point it to the sun?

My first instinct was flexible solar panels and put them on the hatches, but they probably would be shaded a lot by the boom, mast, or sails. So I thought putting them at the stern over the sides, but then they would be fixed and I couldnt point them at the sun.

Unfortunately I cant afford to build an arch for the panels, even though Id love to. Theyre too expensive. Couple thousand pounds.

Ideas are welcome.

 

[paulajayne]

Dauntless had some cheap ready made arches - circa £250 IIRC. Give them a call.

Daunless Yacht Centre

 

[DangerousPirate]

250 quid is affordable. I will. Thank you!

 

[Stemar]

My needs are a lot more modest, so 40w of panels on the hatch garage does me. For a couple of 100w jobs, that wouldn't work, so I can see two possibilities. One is to hang them from the guard wires with folding supports to keep them horizontal when you're at anchor or sailing in gentle conditions. I've seen quite a few boats with that setup, but there's the disadvantage that the panels are vulnerable - especially when you forget to fold 'em down coming alongside. The alternative would be to build your own arch with bits from somewhere like Search results for STAINLESS TUBE. I reckon I could build an arch for my boat for less than £500. The panels would work better for more of the time and, in my hands at least, last longer than panels hanging on the guard wires.

 

[Alan S]

Rigid panels are much better than flexible in terms of watts per square metre, durability and cost, so a pair mounted either side of the cockpit in place of dodgers, hinged at the top could be angled roughly towards the sun. On my boat I have a single 40w panel on a pole which is fully adjustable and I find it works a treat, but not suitable for large panels like 2x100w.

 

[paulajayne]

At the bottom of their first page they are there at £199.

 

[Kelpie]

Guardrail mounted works well for me. I have 100w on one side, soon to be joined by one on the other side.
Don't overthink it. I put mine on in an afternoon using just things that I found on the boat. At one end there is a tube clamp holding it on to the pushpit railing, and at the forward end just a bulldog wire grip onto the guardwire.
I have a pole at the stern which carries GPS aerials etc. I hold the panel up with a line going up to the top of the pole and then down to a cleat. Likewise, a second line from the panel down a cleat prevents the panel from flapping up and down or being completely flipped over by a gust of wind (guess what made me add that refinement...)
I actually get a lot of satisfaction from adjusting the angle throughout the day and then seeing the amps just up. But maybe that's just me.

 

[Kelpie]

And I would second the suggestion of rigid panels. My first one, the cheapest 50w I could find at the time, is still going strong six years later despite having fallen in the sea, dropped eight feet face down on to stones, and being generally abused.
If you have the space, a single 300w panel is incredible value for money at around £100. But if you need smaller panels, you can get a pair of 100w rigids for about £125.

Semi-flexible panels cost four times more and can delaminate after only a couple of years, if subject to regular flexing. I also recently read a scary account of a flexible panel causing a short which set someone's bimini on fire. If he hadn't been aboard at the time and able to tackle it, he might have lost the boat.

 

[doug748]

An arch would murder the performance of a small boat, I would favour the guard wire idea.

.

 

[DangerousPirate]

I was thinking the same thing at first. But I quickly realised that the performance wouldnt be very good.

I do however agree that flexible ones are inferior to rigid ones, and I only mentioned it but I never would havewent for it. Just when I had the idea to put it on the hatches it would be easier and better because rigid ones would be harder to glue/fix and break easier.

The thing with 300w ones are that I dont think I would be able to fix them to the side of my boat. Its rather small, so thats also important if you want to fix them on the sides. I wonder if the cable is good enough for that? I am really not sure. Unfortunately there are not SS tubes running around. Only at the stern and bow.

 

[Pete7]

An arch would murder the performance of a small boat, I would favour the guard wire idea.

Does it though?

Sure if you then hang a dinghy, outboard, liferaft, fenders and everything else you see on some yachts. YT channel Sailing Sophisticated Lady even have a bird cage.

However, what about a an arch with a single horizontal panel? How does that compare to the sprayhood or dodgers for example? Sure it's cumulative, but is a simple arch the end of the world?

DP, there is a pretty good selection of second hand ones on FB Marketplace for ridiculous prices if you can mount a larger panel. Ours is a single 300w and I wonder about fitting two.

Pete

 

[doug748]

Does it though?

Sure if you then hang a dinghy, outboard, liferaft, fenders and everything else you see on some yachts. YT channel Sailing Sophisticated Lady even have a bird cage.......

Pete

It's not for me that's for sure.
It would add loads of windage and maybe 100lbs of stuff right aft. That notional 100lbs would upset the trim and stability and be a nightmare in a strong wind, coming alongside. Stability is not just about keeping the boat the right way up but the ability to carry your sails.
I think you could fairly say it would clobber the performance, mind you I am not a fan of arches on any sailing boat : - )

I do agree that two 100 watt panels would be hopeless, I believe the Pirate's boat in under 25ft.

.

 

[DangerousPirate]

I believe the Pirate's boat in under 25ft.

It is indeed. 22ft.

So I looked into it a little. I might be able to mount them on the side if I replace the top wire with SS tubing. Then I could mount multiple smaller ones. Though I am not sure how easy thats going to be. Maybe its just a few holes to drill and screw, maybe its more to do.
What I dont like about the wire is that you cant properly fix anything to it due to the diameter.

Or I get one of those 360° T Bracket Mounts (or whatever theyre called, Im still googling on that one lol). Put one or two at the stern and I should be good andcould adjust it

An arch is one of those things. I dont know how well that would work, and how to safely do it without welding (I cant weld and hiring someone is gonna cost lots of money). I would only use it for the solar panels, if I use one that is.

 

[RupertW]

Rigid panels are much better than flexible in terms of watts per square metre, durability and cost, so a pair mounted either side of the cockpit in place of dodgers, hinged at the top could be angled roughly towards the sun. On my boat I have a single 40w panel on a pole which is fully adjustable and I find it works a treat, but not suitable for large panels like 2x100w.

Cost yes, otherwise not so

 

[Pete7]

An arch is one of those things. I dont know how well that would work, and how to safely do it without welding (I cant weld and hiring someone is gonna cost lots of money). I would only use it for the solar panels, if I use one that is.

I had similar issues but eventually found a second hand arch which I could modify without welding. The pictures show a 150w panel which has now been changed to 300w because we have a small freezer and they are so cheap it would be a crime not to. I think the weight is about 28kgs, 18 for the 300w panel and another 10kgs for the frame.

At 22ft I think those poles look interesting even if you DIY, or simply mount a panel across the stern attached to the pushpit with these to adjust tonneau support pole - BoatyBits

Pete

 

[lustyd]

My boat might be larger but I also don't want an arch so I've gone for two Renogy 100W flexible panels because they're light and stowable, and seem really well built, and will connect them with an Anderson connector in a locker when needed (aka. at anchor). The panels will sit wherever there is sun on extension leads, this might be on the foredeck, hanging from the boom, or from the guard wires depending on occasion. My old Vivacity would have worked with the same solution so I'm sure it would be suitable on your boat if you want temporary power setup.

 

[Alan S]

Rupert,
How's that?
Can you show me a flexible panel that generates more watts per square meter than a rigid? Flexible panels are prone to delamination as I know to my cost, whereas rigids can last for 20 years or more with output degrading less than 1% per year. I know this from experience. (well, 8 years so far).
Al

 

[V1701]

Don't forget to think about the size of your battery bank also, not much point having 200w of solar if you don't have space for the batteries. If it were me I'd probably keep engine start battery separate and have the solar feed only the house bank, but your set up or pattern of boat use might suit doing it differently...

 

[lustyd]

To be fair flexible ones have seen a lot of improvements recently so delamination is less of an issue. Rigid are still obviously option A though for so many reasons, but if you need them light, thin or bendy rigid is no good

 

[lustyd]

Don't forget to think about the size of your battery bank also, not much point having 200w of solar if you don't have space for the batteries. If it were me I'd probably keep engine start battery separate and have the solar feed only the house bank, but your set up or pattern of boat use might suit doing it differently...

200W is 16A at 12V so bank capacity is unlikely an issue given you may see 100AH in a day if you're lucky. 200W is more about stemming the flow rather than living off grid.