Solar panel on swinging mooring...thoughts

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Matata

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What I'm trying to do is estimate the realistic output from a (say) 30w solar panel sited on a yacht on a swinging mooring. It will be angled at say 45 degrees (depending on the correct attitude) to the horizontal. Bearing in mind it would be on its mooring, unmoved, from beginning May to end of September, on a swinging mooring and therefore prone to tidal/wind direction, good /poor weather, nite /day....you get the idea!
Over that period of time would it be reasonable to guesstimate 1/3?? does this makes sense? Nik
 
Might be best to just mount it flat.
Best results from the sun are when it high up and if you are swinging about, flat will average out.
The sun gives around 1kw/mt sq. Your panel will collect, at best, 500wts if full on, prob a bit less. Then reduced by the angle the sun hits it.
In a fixed marina berth, angling makes sense, but not on a swinging mooring, as the gain from best angle will be cancelled by the worst, when it is facing the wrong way.
Just fitted a 100wt panel on an arch. Flat. But a few years ago I built a few big systems for houses. That is easy to angle for best result, as they don't wander about when the wind blows:o
 
My 140w panels are mounted flat. They do very well in the long hours of summer daylight in Scotland, either sailing, anchored, or on my mooring. I can't see any sense in angling the panels, when you have no control over their orientation.
 
How big is the battery bank? If it's just to keep an 85AH starter battery in good condition then 30w would be fine. And yes, mount it flat...
 
Hi I have a 50watt panel set in the horizontal position feeding 3 100 amp batteries, my boat is also on a swinger on the Tamar, the batteries are always at around 13.4 when I get aboard, I keep her on the mooring all year even in the off season her batteries are kept up to an acceptable level.
 
My boat is on a swinging mooring in summer, and has a 30 watt semi flexible panel flat on the main hatch garage - it works well, the battery is always charged even on overcast days and the shadow of the boom some people worry about seems not to be a bother in reality.
 
Matata said:
What I'm trying to do is estimate the realistic output from a (say) 30w solar panel sited on a yacht on a swinging mooring. It will be angled at say 45 degrees (depending on the correct attitude) to the horizontal. Bearing in mind it would be on its mooring, unmoved, from beginning May to end of September, on a swinging mooring and therefore prone to tidal/wind direction, good /poor weather, nite /day....you get the idea!
Over that period of time would it be reasonable to guesstimate 1/3?? does this makes sense? Nik
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I have a 5 watt Spectralite solar panel mounted at about 40° from horizontal which keeps a 60Ahr battery topped up with ease. Apart from the output from an outboard engine it is the only means of charging the battery..



Somehow or the other my boat has found its way onto the front page of the Spectra Solar brochure https://www.marlec.co.uk/wp-content...Lite-Solar-Brochure-011015.pdf?v=79cba1185463

I believe that the mathematicians can prove that the best position for a panel on a boat on a swinging mooring is lying flat.
 
Seajet said:
My boat is on a swinging mooring in summer, and has a 30 watt semi flexible panel flat on the main hatch garage - it works well, the battery is always charged even on overcast days and the shadow of the boom some people worry about seems not to be a bother in reality.
Click to expand...

That report interests me, I was planning to fit a pair of 20w panels rather than a single panel on the hatch garage because of the theory you refer to, that the boom shadow on only part of a panel would kill the output, my boat is on a fixed mooring facing west so I may be able to keep the boom clear for most of the middle of the day. If the shadow is not a problem one larger panel would have more output and be cheaper.
 
I have a 100 watt flexible solar panel mounted on my spray hood and the boom does shade it but my battery bank is always 100% when I go back aboard.
When cruising it’ll keep the autopilot and instruments running with no issues on a sunny day but the fridge is just too greedy.
 
I've got 110w of semiflexible panels, spread around the boat, for one engine battery and two ah domestic batteries - seems ok for the past year with a fridge running but I do intend to fit another 40w panel this winter making 150w total. Using a dual battery controller, 10% to engine battery and 90% to domestic.
 
Our boat, which is on a swinging mooring, has a 30w panel horizontally mounted above the pushpit charging both the engine and house bank. This works fine: the batteries are always charged when we go on board. We also have two other 30w panels which we position around the boat when we are on anchor or underway. This doesn’t meet all our power needs, but it has greatly increased the time we can go before needing to recharge using the engine
 
VicS said:
Somehow or the other my boat has found its way onto the front page of the Spectra Solar brochure https://www.marlec.co.uk/wp-content...Lite-Solar-Brochure-011015.pdf?v=79cba1185463
Click to expand...

Wow!

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I believe that the mathematicians can prove that the best position for a panel on a boat on a swinging mooring is lying flat.[/QUOTE]

I am a mathematician and I endorse this message.
 
Quandary said:
I was planning to fit a pair of 20w panels rather than a single panel on the hatch garage because of the theory you refer to, that the boom shadow on only part of a panel would kill the output
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Based on threads on this forum, I did exactly this for the same reason using 2 x 20w Photonics Universe panels. I have been slightly kicking myself since as apparently the Photonics Universe 60w panel which would have also have fitted, has a diode arrangement that would make it equally effective in shadow.

Worth investigating.

2 x 20w panels keeps my 2 x 95ah house batteries topped up.
 
20 watt panel mounted flat between forehatch and mast, so no boom shadow to worry about. It feeds two batteries via a PWM controller. Ladybird is on a swinging mooring and since fitting the panel I have never rowed out to find the batteries less than 100%.
 
I've had four boats on swinging mooring with 10 - 20w panels. I'm basically a weekend sailer and found this arrangement provided sufficient power when on board and recharged in between visits. The panels were all fixed semi flex type - no repositioning and always generating whether moored or sailing. I have never had a fridge and power requirements are modest.
If I were to equip another yacht with say 200 ahr of batteries I'd probably put more panel area as prices have plummeted since my first try with solar.
 
For my solar panel project, I've just received a MPPT controller, which is apparently more efficient than the older PWM type.

I've been advised to buy "German" panels, which although more expensive, are thought to be much better than those from the Far East.

I'll be looking for 200watt panels, to add to the AirBreeze wind generator already installed. Both systems are/will be wired directly to the main battery bank which is actually 2 batteries wired in parallel, rather than trying to feed all 4 boat batteries.
 
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JumbleDuck said:
I believe that the mathematicians can prove that the best position for a panel on a boat on a swinging mooring is lying flat...............I am a mathematician and I endorse this message.
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I'm not a mathematician and would only partly agree. If the boat is left unattended then yes leave flat but, if on board, a tilting mount will give far better results by allowing the panel angle to be moved with tide or wind changes, particularly early and late in the day when the sun is lower.
 
Ian_Rob said:
apparently the Photonics Universe 60w panel which would have also have fitted, has a diode arrangement that would make it equally effective in shadow.
Click to expand...

Don't understand what you mean as no panel can be as effective in shadow as it is in sun. The general rule when using multiple panels and one or more are going to be in shadow is to connect in parallel, not series. Interesting video of tests here - https://www.youtube.com/watch?v=1qD3mN8VotQ
 
Molteni said:
I've been advised to buy "German" panels, which although more expensive, are thought to be much better than those from the Far East.
Click to expand...

Wilst "buy German" may work for cars, the Chinese are industry leaders when it comes to solar. I'd have no problem buying them
and indeed intend too this winter.
 
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