Ive started searching around for solar to keep my batteries topped up and planning for later would like opinion on fitting two slim solar panels on my Cabin roof I have roughly 1200 width and thinking that shading causes reduced out put thought maybe two slim panels might be a better arrangement on the Cabin top length 1480 x 350 and add framing rather than one large panel which might have more problems with shading from the boom and rigging
link belowwww.lowenergydevelopments.com.au/75W-Solar-Panel-Monocrystalline
They also have a MPPT controller which would do for now maybe up date in a few years time link below http://www.lowenergydevelopments.com.au/MPPT-high-voltage?product_id=443
I worked out that I needed an 80w panel to keep everything going, but when I looked into the panels
I found that the 100w panel was a fair bit lighter than the 80w panel
and the cost difference was too small to be bothered about.
I got the 100w panel 
So check the weight of the panels [that's not the postage weight but the tare weight].
What I have read is shading reduces the voltage production a larger solar panel can produce . In saying this when a panel produces energy and shade lets say from the boom across some of the larger solar panels cells . The cells on that panel reduces the production of energy by a reasonable amount .
Where two panels below and either side of the boom when one is shaded only one panels energy production will be reduced and the other panel will be in full energy production.
Ive read this a few times which has lead me to believe maybe two small panels might produce more energy than one large panel not so much weight
The picture above is a Walker H28 which has one panel notice the shading from the boom this causes a reduction of how much energy the panel can produce. Then think of two panels either side right next to both grab rails . One panel will be in full energy production the other panel will have less energy produced Which I think will be more than one larger panel.
Maybe I'm wrong but its the result of reading info that has lead me to this
From memory I think it has some thing to do with how the panels cells are wired up when some cell are shaded they switch off all the cells before it in that row of cells and if its its shaded in the second or third row of cells the energy produce by the previous rows will not complete the circuit to produce power (my head knows what I mean but cant put it down on the forum )Ha Ha 
If the shade was on the center of the panel and both sides had sun because of the way the cells are wired in series the energy produce from one side that has sun on it will be disconnected from the series circuit because of the shaded cell in the center and only the cells near the end of the series circuit can produce power. 
maybe this might get it out there Ha Ha
Select to expand quoteHG02 said..
What I have read is shading reduces the voltage production a larger solar panel can produce . In saying this when a panel produces energy and shade lets say from the boom across some of the larger solar panels cells . The cells on that panel reduces the production of energy by a reasonable amount .
Where two panels below and either side of the boom when one is shaded only one panels energy production will be reduced and the other panel will be in full energy production.
Ive read this a few times which has lead me to believe maybe two small panels might produce more energy than one large panel not so much weight
The picture above is a Walker H28 which has one panel notice the shading from the boom this causes a reduction of how much energy the panel can produce. Then think of two panels either side right next to both grab rails . One panel will be in full energy production the other panel will have less energy produced Which I think will be more than one larger panel.
Maybe I'm wrong but its the result of reading info that has lead me to this
From memory I think it has some thing to do with how the panels cells are wired up when some cell are shaded they switch off all the cells before it in that row of cells and if its its shaded in the second or third row of cells the energy produce by the previous rows will not complete the circuit to produce power (my head knows what I mean but cant put it down on the forum )Ha Ha
If the shade was on the center of the panel and both sides had sun because of the way the cells are wired in series the energy produce from one side that has sun on it will be disconnected from the series circuit because of the shaded cell in the center and only the cells near the end of the series circuit can produce power. maybe this might get it out there Ha Ha
I did not mean not so much weight meant to say the weight of either two small or one lager panel was not factored in . I guess you will always have shade problem fitting solar on the cabin roof
Regarding the potentially huge impact of shade: Note that for multicrystalline panels - when a small shadow (say from rigging) occludes part of the panel, the output is less affected than for monocrystaline panels (bigger impact), even though the latter are more efficient and more expensive panels.
Select to expand quoteKarsten said..
Regarding the potentially huge impact of shade: Note that for multi crystalline panels - when a small shadow (say from rigging) occludes part of the panel, the output is less affected than for monocrystaline panels (bigger impact), even though the latter are more efficient and more expensive panels.
In saying that Karsten would you buy two smaller panels 1480x 350 by two or a larger multi crystalline panel to fill the Cabin top void which is 1200 by 1500 roughly between the grab rails finding a solar panel to fit this space is not easy that my main problem
I think your on the right track ...if you break up the panels in to two either side of the rig shade will be less of a problem
its quite dramatic the effect partial shade on the suseptable type of panel is cannot remember mono or poly but it was demonstrated to me by putting a hat on a panel and the effect on voltage output was massive (and it doesnt take much in voltage drop to **** it up)
pity about the mizen ...i have a 40 w poly on the pushpit and works a treat
i have seen 2 thin panels mounted either side of the bow along the bow rail / lifelines and thought it may have its advantages...
my advice is back it up with wind it works at night and packs a punch...but you always have high output diesel alternators which makes things easier
Select to expand quotemadmission said..
I think your on the right track ...if you break up the panels in to two either side of the rig shade will be less of a problem
its quite dramatic the effect partial shade on the suseptable type of panel is cannot remember mono or poly but it was demonstrated to me by putting a hat on a panel and the effect on voltage output was massive (and it doesnt take much in voltage drop to **** it up)
pity about the mizen ...i have a 40 w poly on the pushpit and works a treat
i have seen 2 thin panels mounted either side of the bow along the bow rail / lifelines and thought it may have its advantages...
my advice is back it up with wind it works at night and packs a punch...but you always have high output diesel alternators which makes things easier
I am fitting a Bosch alternator around the 95 amp the Bukh has a 38 amp as original
The Mizzen is a pain for a bimini and solar . it can be done
Dream weaver has a bimini he may have raised the mizzen boom a little perhaps not sure
Which Ill do much the same maybe when at anchor up north Ill add some portables hang them off the side of the rails
By the way Mad Mission With a bit of luck I should have the old girl reasonably sea worth by next summer so when you want a taste of sea water ring me for a sail some weekend you could give me some ideas and recommendations while your on board any way we will catch up soon
Cheers
Select to expand quoteHG02 said..
In saying that Karsten would you buy two smaller panels 1480x 350 by two or a larger multi crystalline panel to fill the Cabin top void which is 1200 by 1500 roughly between the grab rails finding a solar panel to fit this space is not easy that my main problem
Personally, I'd go for smaller panels, of Multicrystaline type (more shade tolerant) because in my case I want good energy capture when I'm not on the boat to shift the boom or panels around to avoid shaded areas.
just a thought for some of you with shading problems: I run a MPPT solar regulator. I have 4 x 55w panels all with some shading from wind generator, rigging and radar. These are 12v panels and I run them in series so that there is 2 x 24v rather than 4 x 12v panels input into the regulator. The MPPT then regulates these down to 12V for charging the battery.
Before hand if any panel had shading then it did not charge (even a single wire rigging shadow across the panel was enough to render the whole panel useless), now if there is some shading on a panel then there is still enough voltage to provide charging as the total panel voltage is 24V and it needs approx 14.5 volts to start charging.
Don't try this unless your MPPT regulator senses the charging voltage of the battery connected to it! only attempt it if all panels connected to the regulator are the same voltage (ie don't mix 12 and 24 v input)
anyone else tried this approach?
For clarification when I say 12V panel, this actually charges at up to 17.1V, so by putting in series the charging voltage is up to 34.2V.
Good advice santanasaga makes sense
lot of discussion on solar at TSP forum
hg02 look forward to a sail on your old girl , i hope to be sailing your way next week ...up for a twilight sail ?
Select to expand quotesantanasaga said...
For clarification when I say 12V panel, this actually charges at up to 17.1V, so by putting in series the charging voltage is up to 34.2V.
Wondering what brand and model controller u are using Santa saga
After u have said this maybe I should buy a single panel with high voltage and a good controller to reduce the voltage down to 12 ??????
some of the mega domestic roof panels (250W) are really cheap.... and put out less than 65V...
This to me simplifies what I would like on the Cabin roof top one high voltage panel and a good controller thanks
a 250 watt panel looks like will fit nicely as well just checked thanks again
Munsterland Solar Panels are made in China, the only thing German about them is the name.
Select to expand quoteLooseChange said..
Munsterland Solar Panels are made in China, the only thing German about them is the name.
I thought as much most seem to be Am hoping to fine a local for Kyocera panel most seem to be up north
HI,
I would personally buy the cheapest, highest power panels that you can fit. more watts = full batteries.
In 2008 I bought a 120w BP solar panel on special at just over $1000... three years ago I bought two 55w panels for $280 each. now you can buy at less than $1 / watt.
I have broken a few panels over the years - my $1000 one copped a loose blade from my wind generator. A cyclone in Tonga took out the 135w replacement...multiple small panels give you the benefit that if you break one, as the others give you redundancy.
the ability of the MPPT regulators to take higher voltage panels opens up the more powerful cheaper terrestrial panels rather than 12v ones. get the best deal you can for the biggest panels you can mount and enjoy the free power.
Many thanks SirJman I think Ill start on the stern and go from there less protrusive than the cabin top . Im just going to finish the motor isolator and LED panel then add and wire in a controller and choose a panel after that as long as it keep my batteries topped up for now so I can listen to some music while I'm working on the boatIll be happy
It's important to make sure that you add fuse/cb protection between your batteries and solar regulator, just in case the reg poops itself. I also use a acr to parallel my batteries, protecting against unbalanced voltages between batteries. My solar feed goes into the battery No.1 side, so if battery No.1 started to fail then you would have to rewire the solar into the battery No.2 side or wait until you replaced the battery No.1...I may put a toggle switch in, but that's another thing to buy.
A caution about that Jaycar MPPT regulator: although it specifies a maximum open-circuit PV voltage of 65V, it also specifies that it is only to be used with 12 or 24V nominal panels. This suggests it shouldn't be used with the cheap domestic panels, which although they have a maximum open circuit voltage around 40-50V, (thus below the 65V), certainly aren't nominal 12 or 24. So be careful. It might be worth contacting Jaycar or the manufacturer if you're thinking of doing this.
I have a single domestic 220W panel with one of these MPPT controllers, which was good value about 3 years ago when I set my system up:
www.gsl.com.au/mppt30.html
My system works well, giving me around 10A (into 12V) in the middle of the day.
Select to expand quoteQLDCruiser said...
A caution about that Jaycar MPPT regulator: although it specifies a maximum open-circuit PV voltage of 65V, it also specifies that it is only to be used with 12 or 24V nominal panels. This suggests it shouldn't be used with the cheap domestic panels, which although they have a maximum open circuit voltage around 40-50V, (thus below the 65V), certainly aren't nominal 12 or 24. So be careful. It might be worth contacting Jaycar or the manufacturer if you're thinking of doing this.
I have a single domestic 220W panel with one of these MPPT controllers, which was good value about 3 years ago when I set my system up:
www.gsl.com.au/mppt30.html
My system works well, giving me around 10A (into 12V) in the middle of the day.
Thanks for that ill look into it ,I sort of have not focused on the solar side just yet mainly sorting out my batteries ,extra battery box for the stardboard side, engine panel and battery isolator . As the boat will mainly be used weekends for the next three years I am thinking of just setting it up similar to Sirjmans and research a power powerful system for when I retire as long as it can top up my batteries after a weekends use for now and keep the batteries healthy .
So for now I think Ill fit a small panel on the stern rails fix it like SirJman has
Select to expand quoteQLDCruiser said...
A caution about that Jaycar MPPT regulator: although it specifies a maximum open-circuit PV voltage of 65V, it also specifies that it is only to be used with 12 or 24V nominal panels. This suggests it shouldn't be used with the cheap domestic panels, which although they have a maximum open circuit voltage around 40-50V, (thus below the 65V), certainly aren't nominal 12 or 24. So be careful. It might be worth contacting Jaycar or the manufacturer if you're thinking of doing this.
I have a single domestic 220W panel with one of these MPPT controllers, which was good value about 3 years ago when I set my system up:
www.gsl.com.au/mppt30.html
My system works well, giving me around 10A (into 12V) in the middle of the day.
I rang Jaycar they said it was OK I also asked where I bought it to. Now Im trying to get a price on a LG mono X neon panel as from my reseach so far surgest there a reasonably good panel
Anything Jaycar said I would take with a large grain of salt, in my opinion they aren't much more than shirt box salesmen.
- for boats are recommended 12 volts devices
/anything higher is trouble sooner or later /
Moisture is constantly present, no connection is perfectly sealed.
Where is the moisture, there is leak, progressively leakage path gets
more conductive and that's the current escape path.
- Second advantage of 12V solar system, when fancy MPPT or
any regulator / cut off switch / fails half way through trip
you connect your panels directly to batteries, no problem, just monitor voltage.
- When you testing panels, there is not much voltage in the shade,
with a bit more light, voltage goes up
with even more light finally you measure 12 volts, connect directly small globe
doesn't lit , why, not enough current yet You still need more light to get current.
Lesson is - ones voltage goes down even fancy reg. function is doubtful
because of lack of current.
- My battery question...my battery in the car/ starts 5 times a day, doing mostly short
trip, last 3 to 5 years,
My boats batteries are calcium good quality, always charges, loosing capacity
after 5 years. Does it mean, regardless how well you look after them,
batteries have life expectancy depending more on brand not how you taking care of them?
