Most efficient panel at 8kg weight?

[Elcid]

Hi everyone,

My current arch has some old solar panels 2x 85W.
The technical dept at Cleopatra Marina, in Lefkas, Greece suggested 2x VICTRON ENERGY 115W, 1015x668×30mm (8kg each) would be suitable for the current arch.

170W to 230W seems like a very small difference. Anyone aware of more efficient panels in this size & weight that I could consider. I was hoping I could find something like the LG Neon 2 Bifacial - but I couldn't find anything small enough.

Current Setup
* Solar panels: 2x85 Watt
* 2x10A Solar Controllers
* Domestic battery : x3 100 AMP/H* (2019)
* Bow thruster Battery: 90 AMP/H ah
* Engine battery : 95 AMP/H
* Inverter: 300 Watt
* Shorepower system (fitted with RCD breaker.)
* Shorepower cable
* Battery charger : Christec 40 Amp (12v/40A)

If nothing more efficient exists, I think it would make sense to keep the current setup as it is. And add a good, big (400W) panel & install it on the side rail perhaps? And when I'll upgrade the arch sometimes later on, I'll already have one good, big panel?

[Elcid]

Two more photos for a better view of the arch

[Quadrille in JB]

Would it be possible to re-orient your PV panels so that the longer dimension is aligned fore and aft? It looks like from your photos that this could be possible with minor additions to your arch. I have mounted 2 Sunpower X22-360 panels on my boat like this. These panels, combined with 2 Victron 100/30 mppt controllers often put out more than the 360W rating of 30 amps each at 12VDC.
I measure the output using the Bluetooth app for the controllers and a separate Victron 702 Power Monitor.
If you could re-orient them they are slightly wider than your existing panels and heavier, but it would be a great investment if your purse and panel mounts can handle it. The panels dimensions are 1558mm x 1046mm x 46mm and they weigh 18.6 kg each.
I have never seen or heard of any PV panels that are more efficient than the Sunpower X22-360s.

[sailorboy1]

I would stop worrying about efficiency as that is about cause. Efficiency is some one's perfect lab test is meaningless far as the few % maybe between different ones. Instead you should think more watts and $/watt. In the end you will be happier with more watts and larger panels than you will about saving a few $$ and higher efficiency.

[sailormed]

When I look at the pictures of the existing installation I would not recommand putting the big Sunpower panels on that arch. It looks like that would be to much load for that construction, you also have to consider wind load, especially when heeled.

[sailorboy1]

man with a couple of alum angle pieces to support the back of panel that arch will hold way more than a couple of solar panels with wind load

[goboatingnow]

My 110W Victrons ( Lefkas ) are mounted like yours on a single tail. I’m upgrading to 2 x 190w ( GWL SOLAR , Czech Republic , $80 each ) mine are mounted using Sk25 linear blocks modified to tighten down on the rail , the bigger panels are mounted in the same orientation as yours as it’s awkward to mount them fore and aft

[Elcid]

Wait - could you please expand on that sailorboy1? If I could fit 2 Sunpower 400W panels up there, that would be perfect.

I kept thinking throughout today and I thought, what if I would install just one panel. Maybe an LG Neon 2 Bifacial 415W - which can output up to 540W: https://www.bimblesolar.com/LG-415W-bifacial-solar-J5

The size is 1024x2024 - and the weight 21kg. Which seems close enough to the two panels recommended, added together 1015x668 (8kg each).

[Elcid]

Originally Posted by Quadrille in JB

Would it be possible to re-orient your PV panels so that the longer dimension is aligned fore and aft? It looks like from your photos that this could be possible with minor additions to your arch. I have mounted 2 Sunpower X22-360 panels on my boat like this. These panels, combined with 2 Victron 100/30 mppt controllers often put out more than the 360W rating of 30 amps each at 12VDC.
I measure the output using the Bluetooth app for the controllers and a separate Victron 702 Power Monitor.
If you could re-orient them they are slightly wider than your existing panels and heavier, but it would be a great investment if your purse and panel mounts can handle it. The panels dimensions are 1558mm x 1046mm x 46mm and they weigh 18.6 kg each.
I have never seen or heard of any PV panels that are more efficient than the Sunpower X22-360s.

Your arch looks very sturdy. A bit more sturdy than what I currently have installed.
I'd really like a couple of Sunpower panels coupled with the Victron MPPT. This was actually what I had initially proposed to the technical department. Alas - the arch is not strong enough in its current state. Unless as sailorboy1 said - it can be improved upon. That would be great.

PS: that looks like a cool system you have there to raise your dinghy! How does it work? Is it connected to the same arch?

[Pete7]

Your arch doesn't appear to have any bracing and probably wobbles side to side. Mine certainly did and needed bracing. The photos below are the frame before I started work on it and after with a 150w panel fitted. I have since upgraded to 300w and am considering doubling that.

However, having fitted the arch and the rear supports I had to add two 3/4" bars to the front to stop it wobbling side to side. This worked and the slightly thinner bars less obtrusive and a useful hand hold. The frame is high enough so that both wifey and I can walk underneath without banging our heads, but equally by standing on the comings I can see on top to clean the panel.

Worth pointing out the for extra struts and connection widgets cost as much as the A frame second hand

Is that a spilt back stay in the first photo? which makes things a little more complicated.

Those panels from Bimble whilst very nice are not 522w. They are 415w plus a bit from the back of the panel which relies on reflected light. Now snow or chalk rocks give a good reflective value. Sadly water isn't very good at reflecting sunlight, so you won't see the return LG initially imply you might.

Pete

[Pete7]

Those Victron panels won't be cheap because you are still in the leisure market and need to be in the 250w plus sized panels for home and industry use which brings the price per watt right down in Europe, hopefully including Greece. As Sailorboy said, it $$ per watt that counts.

You might just have enough room to fit 2 x large 300w+ panels fore and aft with say a 0.5m gap for the split back stay, other wise those panels are going to stick a long way out the back of the boat. You really need to be there with a tape measure to work it all out and were to add the struts to support the extra weight. Perhaps two from the transom angled up and in slightly to the back edge of the panels and another two from the deck or coming also angled up and in slightly to the top of the frame. A couple of old broom handles will do to mock it up before cutting expensive stainless steel tube.

The other cheap option is to start again and sell the existing frame. Since Stainless Steel tube and widgets are very expensive, how about this stuff:

https://www.themetalstore.co.uk/prod...p-uk-suppliers

[Bunji]

Sunman-Energy eArc solar panels

[Pete7]

This is a young couple on a very low budget just starting out, but seem to make the budget stretch really well.

Pete

https://www.youtube.com/watch?v=pgYo...VoyagingVegans

[Elcid]

They sure made it look easy. Is that a good idea to drill holes into the SS tubes though? Won't it compromise its strength?
It sounds like they installed the LG Neon 2 Bifacial 400W. Nice to see them on an install to get an idea on their size. They look massive

[Pete7]

Originally Posted by Elcid

They sure made it look easy. Is that a good idea to drill holes into the SS tubes though? Won't it compromise its strength?
It sounds like they installed the LG Neon 2 Bifacial 400W. Nice to see them on an install to get an idea on their size. They look massive

Actually quite hard to drill through stainless steel and if you go to fast it work hardens the steel then you are completely stuffed. Slow and keep the work cool is the technique, not letting the drill spin, it must keep cutting.

Many arches are made from fittings like this. They hold with a hex grub screw, which I added epoxy. However, I may, go back and drill through the grub screw holes and either tap or bolt all the way through instead just to be safe. Ideally with a shoulder bolt.

Pete