What wattage of solar panels should you try for as a liveaboard.

Nostrodamus said:
Well, we have ordered the arch and solar panels (380w of Kyoceras) and a good Mppt box (morning star).
There is an excellent web page for fitting and using solar panels on boats here

http://roadslesstraveled.us/sailboat-solar/

They suggest fitting the panels in Parallel as it is better for any shade. Also interesting that that do not suggest fitting to the legs to the boat with sikaflex as a sealant.

Does anyone have experience of the best way to wire up multiple panels.. Parallel or series.
Again, thanks for any help.
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The following only applies to 16v panels - I think the situation with 48 and 72 volts is different.
I've tried both ways - and now have a compromise 3 pairs of panels in parallel (each pair in series). Really the result of fiddling - all in parallel slightly increased overall current on most days but gave a very small volts overage from system volts. In series, input voltage is invariably +1.2-1.8 over system volts, which probably means your panels can recharge your batteries.
To sum up series if you wish to charge batteries, parallel if you want to just augment them.
With your proposed wattage I'd tend toward series but if starting again I'd bypass the dilemma by going for 48v output from single panels. It's significant that 16v panels require a considerably greater overall irradiated area to produce the same current as a 48 volt one. I suspect the parallel-superior hypothesis is more urban legend than proven fact - the larger panels have the same type of cells but in a series configuration.

The various Kyocera configurations are here; http://www.kyocerasolar.com/assets/001/5133.pdf.
You will note that the panels being supplied to you are different to these and, probably, obsolescent stock.

It's notable that working output voltage is now considerably different (lower) from that on the earlier KD series (which I have)
 
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Nostrodamus said:
Well, we have ordered the arch and solar panels (380w of Kyoceras) and a good Mppt box (morning star).
There is an excellent web page for fitting and using solar panels on boats here

http://roadslesstraveled.us/sailboat-solar/

They suggest fitting the panels in Parallel as it is better for any shade. Also interesting that that do not suggest fitting to the legs to the boat with sikaflex as a sealant.

Does anyone have experience of the best way to wire up multiple panels.. Parallel or series.
Again, thanks for any help.
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Very interesting and practical article. Fabulous welding! Don't understand your comment about Sikaflex, they used 3M 4200 that is pretty much identical with Sikaflex 291. You definitely need a sealant to prevent crevice corrosion. Our panels are wired in parallel, but with a PWM controller I don't think there is another option.
 
vyv_cox said:
Very interesting and practical article. Fabulous welding! Don't understand your comment about Sikaflex, they used 3M 4200 that is pretty much identical with Sikaflex 291. You definitely need a sealant to prevent crevice corrosion. Our panels are wired in parallel, but with a PWM controller I don't think there is another option.
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It was interesting they over drilled the holes for the feet, countersunk it and then put epoxy into the holes before fixing them. It apparently gives a little bit of flexibility with less chance of leakage. On anothersite they used some form of tape or sticky stuff on the bottom of the legs which they then cut the excess off which they bsaid was more flexible than using siksflex
 
Nostrodamus said:
Found the site again now.
Pretty amazing for marine jobs of all kinds.

http://www.pbase.com/mainecruising/boat_projects
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There is a thread on PBO at present where butyl is discussed. It goes on extruding for ever and my own opinion is that it would not be ideal in a heavily loaded application like legs on a panel arch, as it would not be too long before there was none left. If the only requirement is for it to keep water out that might be fine, but you are suggesting that the mastic is needed for its elastic properties, which butyl does not have.
 
Right,, I have everything now and just have to put it all together although I had so many different theories on what guage wire to use.
As I said I am a total thicky when it comes to Electrickery and to show how thick here is a simple question.
I know that electricity has to flow and it will try and go from a higher load to a lower load. To make it do this you need a negative as well as a positive to complete the circuit. What baffles me is what does the negative wire carry and on a circuit like a solar circuit does the negative lead need to be as thick as the positive lead or can it be of thinner wire.
Please enlighten me?
 
blampied said:
Hi Nostrodamus.
Can't vouch for the longevity of the semi flexible panels,
Only purchased them via e.bay direct from China last year, about £180 each,
they are still working fine so far, and I'm happy with them.
We only have a 33' motor boat, and the solid ones would have been too heavy / unsightly.
They provide far more than needed during the day, so wouldn't add more panels even if I had the room,
a bigger battery bank (we only have 360 ah bank) would be more usefull to store the excess of the day for the evening.

Any suggestions for what to do with the boat over the winter?
We could stay with the boat but would prefer to return home to Jersey for the deepest part of winter.
We came through the French canals taking 4 months to reach the Med,
Came out at Port st Louis two weeks ago, been as far as Cassis and currently in Marseille!

Port st Louis is a possibility, cost about £1700 to lift out and back in.
Port Nepolian the same, but about £2000
Not sure I want it lifted out in this area due to many stories about the winter Mistral getting to 20c below, causing freezing problems for boats not kept in the water.

Best regards
Paul
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Sorry but Port Saint Louis does not have lift out facilities! :)

Port Napoleon - yes.
Navy Service - yes
Port Saint Louis - no.

3 separate entities.

Fascinated by the reports of -20c!!
Mistral - yes
in 10 years wintering in P.Napoleon we had one winter where the temperature was -8 at night and remained at -1 to 2 during the day this lasted for appx 7 days. Normal winters the temps can drop to below freezing at night but by midday the temps are always +
Leaving a boat out of the water in the winter should always mean that the engine is winterised and the fresh water system drained down and the taps left open.
 
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Nostrodamus said:
Right,, I have everything now and just have to put it all together although I had so many different theories on what guage wire to use.
As I said I am a total thicky when it comes to Electrickery and to show how thick here is a simple question.
I know that electricity has to flow and it will try and go from a higher load to a lower load. To make it do this you need a negative as well as a positive to complete the circuit. What baffles me is what does the negative wire carry and on a circuit like a solar circuit does the negative lead need to be as thick as the positive lead or can it be of thinner wire.
Please enlighten me?
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The neg wire is just as important as the pos and needs to be the same size. Whats important for solar is the volt drop across the whole circuit, there and back (or pos and neg). That counts both from the panels to the controller and from the controller to the batts, the nearer you can get the controller to the batts the better as thats the more critical voltage. Arguably slightly less important from the panels to the controller as the voltage may be higher, especially if you connect panels in series (but watch for shading). Use the largest wire that will fit your controller, mines AWG 6 (c.13mm2) which is what I've run from the panels and on to the batts.
 
Thanks Robbie, I knew there would be someone with some common sense. The advice on the wire size went from 4mm right up to 25mm. Probably the best advice I got was to forget about the calculations and just fit the biggest wire you can. Now I am just wondering if the undersea line laying boat will miss that coil.
 
Don't know what the import situation is in Europe nowadays but we ordered 3kw of panels semi flexible and light from china.
Expecting avaerage to poor quality we were not disapointed.. We have 1200w on the boat. The more the merrier and don't bother with tilting etc.
These can of course be mounted in series with a good mppt charge controller. We chose morningstar because there are no fans ! and they will tack up to 150 voc of panels.
If we are not on the boat we turn half off but leave the fridge;/freezer on all the time.
Best move we ever made at around 1.50usd per watt.
 
Thoughts of this year...........In the spring and summer this year, 160watts of panels were more than adequate to meet all my needs and more. However, come October a different picture emerges with the panels only just coping. The fridge turns itself off at 11 volts and I suppose this occurred in the middle of the night as it is on 24/7. My advise would be to go for the biggest panels possible (without going over the top), 6mm cabling and a decent controller. I used a dual controller that boosted the house batteries before charging the engine one then went into float mode. Hope this helps.
 
emmalina said:
Don't know what the import situation is in Europe nowadays but we ordered 3kw of panels semi flexible and light from china.
Expecting avaerage to poor quality we were not disapointed.. We have 1200w on the boat. The more the merrier and don't bother with tilting etc.
These can of course be mounted in series with a good mppt charge controller. We chose morningstar because there are no fans ! and they will tack up to 150 voc of panels.
If we are not on the boat we turn half off but leave the fridge;/freezer on all the time.
Best move we ever made at around 1.50usd per watt.
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EU imposed anti-dumping duties on chinese panels, which started @ the beginning of this year for 2 years.
Top quality polycrystalline panels cost about £3/watt, amorphous about 50% of that price - however you need x3 the area to get the same output. I know of no semi-flexible amorphous panel with an extended output warranty and, whilst they're a lot lighter than poly/monocrystalline panels they're not 1/3 the weight,
Most don't have as large a boat as you appear to have, so finding the area for 1.2kW of amorphous PV panel would be a major challenge.
As finding the area to mount a large wattage of PV panels appears to be the limiting factor for most yotties - buying the big multi-array domestic panels would appear the best solution; 36v (80 cells) ones produce about x1.4 the watts/m2 compared to 12v (36 cells) ones and the speed of improvement in efficiency is startling. 10.8% in 2000, 12.3% in 2008 and over 18% now.
The two amorphous, semi-flexible panels I bought are down to 60% of rated output after 5 years - the glass, polycrystalline KC pairs are producing 82 and 85% respectively. (One will never get the nominal output of any panels under user conditions).
I'd tend to agree that trying to angle them to follow the sun is a chore, even if you'll get about 20% more output. More effort-effective to just have a larger area, but winter output is, in my experience about half what you can expect in summer (unless you're on the equator) so, an all-the-year round liveaboard needs twice as much panel-area than he does in summer.
I get by during the 3 summer months in Greece on 330 watts of PV panel - by October I need to find an additional source of charge after about 3 days
 
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I manage with only 180watts of PV panels plus morning motoring in the med summer. Seems plenty to me but I do switch the top loading fridge off at night. I have lashed out on expensive Sunware panels. And in fact after contacting Sunware direct, they have just replaced free a faulty panel that was three years old. My last three have been 48wt panels that will deliver 2amps each at midday, rather than the 4 amps you might expect, so my rule of thumb is a max of "50%"! They can be screwed directly to a slightly curved deck, easier on a multi of course. In fact I have two panels on the wash lashed floats, Sunware insist they're waterproof!!
 
tri39 said:
I manage with only 180watts of PV panels plus morning motoring in the med summer. Seems plenty to me but I do switch the top loading fridge off at night. I have lashed out on expensive Sunware panels. And in fact after contacting Sunware direct, they have just replaced free a faulty panel that was three years old. My last three have been 48wt panels that will deliver 2amps each at midday, rather than the 4 amps you might expect, so my rule of thumb is a max of "50%"! They can be screwed directly to a slightly curved deck, easier on a multi of course. In fact I have two panels on the wash lashed floats, Sunware insist they're waterproof!!
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Your delivered amps seem rather low, does your installation suffer from excessive shadow or are the cables somewhat on the light side? My 130watts of panels deliver 8 amps at midday in midsummer. I was unable to include a third panel in the network because my controller has a limit of 9 amps. My fridge remains on 24/7, switching it off at night in ambients of more than 30C could be a health risk. Up to September my panels are fully sufficient for power but in October we struggle with 12 hours of near darkness.
 
vyv_cox said:
Your delivered amps seem rather low, does your installation suffer from excessive shadow or are the cables somewhat on the light side? My 130watts of panels deliver 8 amps at midday in midsummer. I was unable to include a third panel in the network because my controller has a limit of 9 amps. My fridge remains on 24/7, switching it off at night in ambients of more than 30C could be a health risk. Up to September my panels are fully sufficient for power but in October we struggle with 12 hours of near darkness.
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VYV , what size battery bank do you have ? We have 440 house , useable 220 and three panels of 65w we managed fine in the summer , we can sit at anchor as along as we like but as you say come oct it a different story , we do have a lot of uses , right down to a 3000w inverter , although we never use 3000w one panel is always shaded but now in Nov we lucky if we see 3amp at mid day .just now it very over cast and we seeing 2.6 but that the wind gen , I would imagine
The panels are putting nothing In at the moment , we Thinking of removeing them all and buying two 150 panels althought I still don't think we manage .
 
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I suppose I might reach 7-8amps if all four panels were simultaneously fully irradiated! But I don't think it's ever happened.
The wires are 3mtrs long and supplied with the panels, and the two on the floats are that far away from the batteries.
Altho the fridge is off at night, it's on all day since I've binned the thermostat, so we eventually freeze beer cans which provide the
"holding plate" overnight. But we never have meat in the fridge overnight anyway, still use a lot of (heavy) tins.
The cheap ammeters might be undereading a little bit. And I should probably clean the batt connections more often.
 
sailaboutvic said:
but now in Nov we lucky if we see 3amp at mid day .just now it very over cast and we seeing 2.6 but that the wind gen , I would imagine
The panels are putting nothing In at the moment , we Thinking of removeing them all and buying two 150 panels althought I still don't think we manage .
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Assuming full sun and not a long way from where I am (SW Turkey), 3A seems very low from 195W of panels. Yesterday mine were showing 13A at solar noon, from 4 panels totalling 340W (with a little shading on at least one). On that basis one would expect yours to be putting out around 7.5A. At the time my 450Ah of batteries were discharged by about 25% after a couple of very cloudy days.

Generally 340W allows us to cope reasonably well at this time of year, largely because the heaviest consumer, refrigeration, isn't working so hard.
 
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