Power generation

[George94]

 

I assume that you have the FM60 controller. I would be happy to put all of your intended 900watts through that controller.

 

There will only be an excess in summer. In winter the total array wont be hitting the peaks for very long. Also remember that the actual charging voltage will be higher than 12v nom. So 900watts / 14v is only 64amps. The main issue is max peak array voltage. The panels will also need to be closely matched in peak V or peak amps depending on how you wire them.

 

I have 1200watts going into a FM80 & a 12v nom battery bank. Yes it caps the peaks but even in summer thats not for very long.

 

Is it true of MPPT controllers generally that they will simply cap the excess volts/amps, or will the cheaper ones get fried?

[Justme]

Be careful there.

 

They can cap amps but not volts.

 

Over voltage nearly always results is a hit to the bank balance.

 

I cant say about the cheap ones but all the good makes will cap the excess amps quite happily.

[George94]

Be careful there.

 

They can cap amps but not volts.

 

Over voltage nearly always results is a hit to the bank balance.

 

I cant say about the cheap ones but all the good makes will cap the excess amps quite happily.

 

Thanks. I see what you are saying. I was thinking of getting panels with too much capacity for summer, so as to have more output in winter, and was hoping that an underspecc'd charger would simply cap the excess in summer, whilst being OK for winter.

 

In other words, get 1200 watts of panels and a 600 watt charger, on the basis that the panels will never produce 600 watts in winter, and the charger will simply lose the excess in summer. But probably I have overlooked some vital point.

[Justme]

 

Thanks. I see what you are saying. I was thinking of getting panels with too much capacity for summer, so as to have more output in winter, and was hoping that an underspecc'd charger would simply cap the excess in summer, whilst being OK for winter.

 

In other words, get 1200 watts of panels and a 600 watt charger, on the basis that the panels will never produce 600 watts in winter, and the charger will simply lose the excess in summer. But probably I have overlooked some vital point.

 

What you are suggesting can be ok as long as its the amps that are over spec & not the volts (and the controller supports it). Also dont think of it as a 600 watt charger. They are speced in output amps not input watts. Another thing is that the panels will produce their full rated wattage in winter, just not for very long. You can even get the situation where they over produce for a short while as they are cold.

[Redeye]

 

That's really interesting justme Cheers. I actually wondered if that was doable.

 

We currently have 2 x 250w panels polycrystalline and one 140w panel mono crystalline around 35v per panel.

 

I'm hoping I could use these

 

http://www.titan-energy.co.uk/sale--80w----semi-flexible-mono-solar-panel-107-p.asp

 

We're currently wired in series but happy to go parallel if need be. If I could incorporate in series though they could be added with no additional wiring which would be a big bonus.

 

Hi all,

 

I have a historic boat with a conversion so don't want to stick solar to the roof of the boat, I have considered sticking some flexible panels to flexible magnetic strip so we can temporarily put them on the roof while cruising, cables could be fed through the pidgeon box in the engine room.

 

Any thoughts on how feasible this might be.

 

Thanks

 

Andrew

[George94]

 

What you are suggesting can be ok as long as its the amps that are over spec & not the volts (and the controller supports it). Also dont think of it as a 600 watt charger. They are speced in output amps not input watts. Another thing is that the panels will produce their full rated wattage in winter, just not for very long. You can even get the situation where they over produce for a short while as they are cold.

 

That's good to know. Interestingly, the FM80 is hardly any more expensive than the FM60 (£475 versus £425), and although other manufacturer's units are (considerably) cheaper, the Outbacks come with a 5 year guarantee, which is encouraging.

 

So, in view of what you have said, I am now thinking of going for one of them, together with four Yingli 220s from Bimble, and then perhaps doubling the number of panels come the winter. Two parallel banks of four panels in series would give roughly 15A at 120V into the controller, which itself is rated at 150V max. So if the controller will cap the amps when necessary, that should work.

 

Fortunately I have the space.

 

Thanks!

[Arthur Brown]

I have often wondered about fitting solar as "panels" on the cabin sides. With all the correct lining detail! Lets some panels see the low winter sun and the low evening sun in the summer. One side will do nothing but the other should have a long solar day whatever the season.

[Kae]

I have often wondered about fitting solar as "panels" on the cabin sides. With all the correct lining detail! Lets some panels see the low winter sun and the low evening sun in the summer. One side will do nothing but the other should have a long solar day whatever the season.

 

One of the regular shufflers on our stretch of canal has this effect. It's different...

[Justme]

 

the Outbacks come with a 5 year guarantee, which is encouraging.

 

So, in view of what you have said, I am now thinking of going for one of them, together with four Yingli 220s from Bimble, and then perhaps doubling the number of panels come the winter. Two parallel banks of four panels in series would give roughly 15A at 120V into the controller, which itself is rated at 150V max. So if the controller will cap the amps when necessary, that should work.

 

Fortunately I have the space.

 

Thanks!

 

 

I have used the warranty, its good. Sent a new unit our before picking up the old.

 

Is that 120v at Pmax or OCV?

 

If Pmax them do the temp coefficient calc to make sure it still under 145-150v. Your looking at about a 5 to 6v gain for every deg c under its rated temp. If rated temp is 20c & you get a -15c winter your controller is toast.

 

 

Why just fit the extra panels in winter?

 

Save on LPG & use a leccy kettle & immersion. The outback can turn devices on dep on lots of options..

[Ex- Member]

 

Hi all,

 

I have a historic boat with a conversion so don't want to stick solar to the roof of the boat, I have considered sticking some flexible panels to flexible magnetic strip so we can temporarily put them on the roof while cruising, cables could be fed through the pidgeon box in the engine room.

 

Any thoughts on how feasible this might be.

 

Thanks

 

Andrew

 

If you have a mast you could hang them like sails on a cross beam. Drape down cabin sides. I was thinking that fo ours, perfect angle for the winter sun.

[bizzard]

No need to spoil the looks of a historic boat with these unsightly panels on the top, just stick circular solar panels to the brim of a ginormous Sombrero had and just sit in the sun drinking whilst wearing it until your batteries are charged up. The wires can be hidden by feeding them down through your shirt and away down through a trouser leg and out and away to its plug socket.

[George94]

 

 

I have used the warranty, its good. Sent a new unit our before picking up the old.

 

Is that 120v at Pmax or OCV?

 

If Pmax them do the temp coefficient calc to make sure it still under 145-150v. Your looking at about a 5 to 6v gain for every deg c under its rated temp. If rated temp is 20c & you get a -15c winter your controller is toast.

 

 

Why just fit the extra panels in winter?

 

Save on LPG & use a leccy kettle & immersion. The outback can turn devices on dep on lots of options..

 

Hmm. I will do some calculations.

 

The reason for winter augmentation is partly cash flow, and partly that my circumstances might change before then - I might have shore-power.

 

But I take your point. Boiling the kettle probably uses a good 20% of my gas.

 

Thanks again.

I have often wondered about fitting solar as "panels" on the cabin sides. With all the correct lining detail! Lets some panels see the low winter sun and the low evening sun in the summer. One side will do nothing but the other should have a long solar day whatever the season.

 

That strange all-electric barge that was on sale a while ago had the panels placed on the side of the hull. The idea was that reflections from the water would add significantly to the light falling on the panel.

[Ex- Member]

I have often wondered about fitting solar as "panels" on the cabin sides. With all the correct lining detail! Lets some panels see the low winter sun and the low evening sun in the summer. One side will do nothing but the other should have a long solar day whatever the season.

 

With panels on boat sides you'r comment that on one side the panels would do nothing isn't really correct. Solar panels require light not necessarily direct sunlight, so panels on the non sunny side will still glean some energy but obviously at a much lower level than the sunny side.

 

For boat sides I reckon Polycrystalline would be better as they are better at lower light levels.

 

I was thinking of rigging something so I could move panels from one side of the boat to the other depending on what way we're facing. We have a nice solid handrail and could easily rig something to neatly and securely hook over it to drape flexi panels on cabin sides. Perfect for low winter sun.

[MyLady]

Julynian: "For boat sides I reckon Polycrystalline would be better as they are better at lower light levels."

Have you a reference to an explanation of the differences, advantages and disadvantages of mono- versus poly- (and to which of the two classes do 'semi-flexible' panels belong)?

Needing to learn,

Roger

Edited May 14, 2014 by MyLady

[Robbo]

 

Julynian: "For boat sides I reckon Polycrystalline would be better as they are better at lower light levels."

 

Have you a reference to an explanation of the differences, advantages and disadvantages of mono- versus poly- (and to which of the two classes do 'semi-flexible' panels belong)?

 

Needing to learn,

 

Roger

I'll try and find the link I have, it's not that mono panels are worse in indirect light than poly but they are no better so there's no point in spending the extra on mono unless your going to direct them towards the sun.

 

The flexible panels I've seen are mono.

[Robbo]

Here we go...

 

http://energyinformative.org/best-solar-panel-monocrystalline-polycrystalline-thin-film/

 

 

Monocrystalline Silicon Solar Cells

Solar cells made of monocrystalline silicon (mono-Si), also called single-crystalline silicon (single-crystal-Si), are quite easily recognizable by an external even coloring and uniform look, indicating high-purity silicon, as you can see on the picture below:

Monocrystalline solar panels

Monocrystalline solar cells are made out of silicon ingots, which are cylindrical in shape. To optimize performance and lower costs of a single monocrystalline solar cell, four sides are cut out of the cylindrical ingots to make silicon wafers, which is what gives monocrystalline solar panels their characteristic look.

A good way to separate mono- and polycrystalline solar panels is that polycrystalline solar cells look perfectly rectangular with no rounded edges.

Advantages

Monocrystalline solar panels have the highest efficiency rates since they are made out of the highest-grade silicon. The efficiency rates of monocrystalline solar panels are typically 15-20%. SunPower produces the highest efficiency solar panels on the U.S. market today. Their E20 series provide panel conversion efficiencies of up to 20.1%.[3] Update (April, 2013): SunPower has now released the X-series at a record-breaking efficiency of 21.5%. [7]

Monocrystalline silicon solar panels are space-efficient. Since these solar panels yield the highest power outputs, they also require the least amount of space compared to any other types. Monocrystalline solar panels produce up to four times the amount of electricity as thin-film solar panels.

Monocrystalline solar panels live the longest. Most solar panel manufacturers put a 25-year warranty on their monocrystalline solar panels.

Tend to perform better than similarly rated polycrystalline solar panels at low-light conditions.

The efficiency of individual solar cells is higher than for entire solar panels/modules. For a complete overview over how the efficiency rates of the various solar cell technologies have advanced since 1975 check out Best Research-Cell Efficiencies (NREL). The efficiency rates in this article refer to solar panel/module efficiencies. Check out What Factors Determine Solar Panel Efficiency? for more information on this subject.

Disadvantages

Monocrystalline solar panels are the most expensive. From a financial standpoint, a solar panel that is made of polycrystalline silicon (and in some cases thin-film) can be a better choice for some homeowners.

If the solar panel is partially covered with shade, dirt or snow, the entire circuit can break down. Consider getting micro-inverters instead of central string inverters if you think coverage will be a problem. Micro-inverters will make sure that not the entire solar array is affected by shading issues with only one of the solar panels.

The Czochralski process is used to produce monocrystalline silicon. It results in large cylindrical ingots. Four sides are cut out of the ingots to make silicon wafers. A significant amount of the original silicon ends up as waste.

Monocrystalline solar panels tend to be more efficient in warm weather. Performance suffers as temperature goes up, but less so than polycrystalline solar panels. For most homeowners temperature is not a concern.

This article is solely about different types of solar panels. If you want to learn about what other equipment a photovoltaic system consists of, go to Grid-Tied, Off-Grid and Hybrid Solar Systems.

Polycrystalline Silicon Solar Cells

The first solar panels based on polycrystalline silicon, which also is known as polysilicon (p-Si) and multi-crystalline silicon (mc-Si), were introduced to the market in 1981. Unlike monocrystalline-based solar panels, polycrystalline solar panels do not require the Czochralski process. Raw silicon is melted and poured into a square mold, which is cooled and cut into perfectly square wafers.

Polycrystalline solar panels

Advantages

The process used to make polycrystalline silicon is simpler and cost less. The amount of waste silicon is less compared to monocrystalline.

Polycrystalline solar panels tend to have slightly lower heat tolerance than monocrystalline solar panels. This technically means that they perform slightly worse than monocrystalline solar panels in high temperatures. Heat can affect the performance of solar panels and shorten their lifespans. However, this effect is minor, and most homeowners do not need to take it into account.

Disadvantages

The efficiency of polycrystalline-based solar panels is typically 13-16%. Because of lower silicon purity, polycrystalline solar panels are not quite as efficient as monocrystalline solar panels.

Lower space-efficiency. You generally need to cover a larger surface to output the same electrical power as you would with a solar panel made of monocrystalline silicon. However, this does not mean every monocrystalline solar panel perform better than those based on polycrystalline silicon.

Monocrystalline and thin-film solar panels tend to be more aesthetically pleasing since they have a more uniform look compared to the speckled blue color of polycrystalline silicon.

Edited May 15, 2014 by Robbo

[Paul's Nulife4-2]

What a brilliant post Robbo, well done and thank you.

It would be interesting to make the same comparisons with 'Amorphous' Panels, I've got a very small 120w installation, laying almost flat (well approx 15°) and they do tend to thrive in lower light conditions, therefore have a longer 'Working Day' !.& possibley the cheapest option.

Obviously I know they couldn't compare to the others in output terms, in direct sunlight/Daylight per say, but are definitely fit and forget (imo). And over the winter could possibly be a better choice (Don't know, just a guess).

Edited May 15, 2014 by Paul's Nulife4-2

[Robbo]

What a brilliant post Robbo, well done and thank you.

It would be interesting to make the same comparisons with 'Amorphous' Panels, I've got a very small 120w installation, laying almost flat (well approx 15°) and they do tend to thrive in lower light conditions, therefore have a longer 'Working Day' !.& possibley the cheapest option.

Obviously I know they couldn't compare to the others in output terms, in direct sunlight/Daylight per say, but are definitely fit and forget (imo). And over the winter could possibly be a better choice (Don't know, just a guess).

 

If you follow the link it goes into other solar panel technologies including Amorphous types.

 

Direct link; http://energyinformative.org/amorphous-silicon-solar-panels/

Edited May 15, 2014 by Robbo

[Paul's Nulife4-2]

Brilliant, Thanks again Robbo,

Pretty much as I said and expected through my experience of them over the 3 years I've had them. I like them,( But for me, still favour Wind as a higher and more reliable power source )

[MyLady]

If you follow the link it goes into other solar panel technologies including Amorphous types.

 

Direct link; http://energyinformative.org/amorphous-silicon-solar-panels/

 

Thanks very much Robbo. I'm learning.

 

Roger

[Robbo]

Brilliant, Thanks again Robbo,

Pretty much as I said and expected through my experience of them over the 3 years I've had them. I like them,( But for me, still favour Wind as a higher and more reliable power source )

 

I'm looking more and more at solar and looking at getting around 600w worth of semi-flexible mono panels, as these will go on my wheel house roof. For security and lazyness I'll be having them flat and suffer the loss that this will occur (around 20%-30%?).

[Paul's Nulife4-2]

Yes,

That's my view on solar as well, if it can be mounted in a way that is lets say out the way,& unobtrusive it's a pay of with potential power lost.but more fit and forget & user friendly.

All be it, not as efficient !.

https://db.tt/WkiFue5A

This is my tiny but conveniently mounted installation, (4 x 30w Amorphous panels + Wind Gen) but tends to work for me.

Regularly getting 36A hr a day (over 24hr) from Wind.

And 28A hr a day (over approx 14hr) from Sol.

 

Massively fluctuating sometimes More, Sometimes less, Depending on conditions favoring Device and Battery SOC at the time ofcourse.

Edited May 15, 2014 by Paul's Nulife4-2

[oarfish]

What a brilliant post Robbo, well done and thank you.

It would be interesting to make the same comparisons with 'Amorphous' Panels, I've got a very small 120w installation, laying almost flat (well approx 15°) and they do tend to thrive in lower light conditions, therefore have a longer 'Working Day' !.& possibley the cheapest option.

Obviously I know they couldn't compare to the others in output terms, in direct sunlight/Daylight per say, but are definitely fit and forget (imo). And over the winter could possibly be a better choice (Don't know, just a guess).

We have 260 watts of amorphous solar on the roof, with another 260 waiting to go up. They give out about 40W on an overcast day. But most of the advantage comes from their low profile and robustness / difficulty to steal etc. I believe they are the same panels used on that 'bauhaus barge', but we are not trying to run an engine from them

 

 

 

Edited May 30, 2014 by oarfish

[peterboat]

I have 800 watts of xunpower flexible panels to go on shortly cant wait to get rid of the rigid panels but I need a warm day so that they will flatten out and look neat

 

Peter

[Paul's Nulife4-2]

Hi ya Oarfish,

What a unique Hatch Cover / Entrance you've got, I know it may not be everyone's cup of tea, but I like it.

Did you make it yourself !.

 

Ref your Solar installation, Very nice, low profile & neat installation you've got. how do you find the power returns overall on ave, compared to total installation cost ?

My small 120w installation was about £150, and Ime very happy with them (now, after finding a bad connection a few months back).

As I say, the return I get fluctuates massively, depending on Weather, SOC of Battery Bank ect ect. But yep very happy. Will definitely be getting a 1000w of Solar installation and two

Rutland 914s Wind Generators on my next boat.

Putting my Realistic Actual Average Harvest around 200AH (at a guess) a day if I need it.

Obviously this again Will vary massively.

Edited May 30, 2014 by Paul's Nulife4-2