# solar output help .



## 88726 (May 9, 2005)

hi guys
ive been looking into building or buying some solar power . ive spent ages on ebay but the longer i look the more confused i get as theres so many types , sizes , and trying to work out price for power is draining me.

firstl what type is best ?
monocrystaline .
polycrystaline .
amorphous .
any others ?

i want something that can easily keep topped up 2 x85ah leisure batteries whilst i drain them. even on a slightly sunny day . i dont mind fixing a couple of large panels on the roof and i dont mind building my own as i nearly bought a hundered or so cells in an auction thinking i could build a couple of 80 watt panels that together could probabally supply about 60 watts in the uk sun but im not sure that my sums add up as theyre described so differently eg some in watts , mah , and some per panel and some per individual cell . the most demanding thing i would run is a 50 watt tv or maybe my laptop but i just cant imagine these panels coming close . 
i have searched the forum and found some info i need but i know the electrical techies here will know the score

please note this is another of my weird projects and i will probabally end up building something and eventually post some pics :lol: :lol: :lol: :lol: 
cheers
kenny+stella


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## Anonymous (Nov 10, 2000)

Hi Kenny,

Have you looked at these to sites?

http://www.goodideacreative.com/solarpanel.html
http://www.siliconsolar.com/

The US dollar > GBS is very good at the moment.

Doug...


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## 88724 (May 9, 2005)

Hi Kenny


Amorphous panels are the best, because these panels work better when they get hot ie produce more power, secondly these can be slightly shadowed without losing most of their output. Of course these cost more.

working out price per power watt will probably show the monocrystaline to be better, but just one bird splat will render the system powerless and on hot days you will lose power again. Amorphous is definately the better panel.

George


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## 88726 (May 9, 2005)

hi guys
thanks for the info . 

doug : i spotted the ebook in a search here and im keping it in mind . im a bit wary of buying more expensive stuff outside the uk due to being stung for duty once already . 


george : i never knew that a bird splat could render the whole thing useless i would never have guessed that . ive seen adverts claiming that different types work best in cloudier/ shaded conditions and theres a huge contradiction between adverts .

theres also a big variation in physical size of these cells . 
how many watts do you guys think i need to make a decent battery charger ?
im also assuming i may only get about a third of the power stated to be realistic .
huge thanks
kenny+stella


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## 88724 (May 9, 2005)

Hi Kenny

Powerless is probably too strong a word, but only just, but a bird splat will take away far more power than you would expect nearly all the power from a mono panel

An amorphous or Uni solar panel will lose much less.

Anything above 60w will make a decent charger, but it depends on your usage per day whether it will charge enough.

Make a list of items you run each day and for how long, will give you an idea of how much power you need to generate

George


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## 92046 (May 1, 2005)

*Solar panels*

Hi Kenny

Your size of panel will depend on your load, batteries to charge, and the location of use, your batteries will depend on your reserve required, (night time load and duration)
A word of warning, these panels run "hot" when on load, must be kept clean for a good output, however, I have seen a 20 watt panel with 6 holes in it and still working, with around 50% output,

Dimensions for a 120 watt panel is around L 113cm, W 99cm, D 5cm,
80 watt panel is around L 111cm, W 66cm, D 5cm,
50 watt panel is around L 94cm, W 50cm, D 5cm,

these are Polycrystalline low lead, glass panels, and the output voltage is around 21 volts for a 12 volt panel, so the use of a regulator is highly recommended,

As for voltage output, some people only use a small panel, ie; 10-20 watt and do not use a regulator, this is okay for a large lead acid battery, with a large panel, the battery can get overcharged, and a 2nd point if no regulator is used the solar panel MUST be connected to the battery, and to disconnect the battery, all the outgoing load must be disconnected first, and the solar panel disconnected last, without a regulator the electrical load must not be connected to the solar panel, as with no regulator you may get around 20 or so volts into the system, the regulator will controle the voltage to around 14.0 volts,

I have 2 x 50 watt panels fitted, used to be 3, but removed 1 as not required, but I do not use a TV, and I have another smaller panel to put outside for the engine battery, ((radio/cd player of engine battery))
Good luck with the project
Colin


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## 88726 (May 9, 2005)

hi guys
thanks again for the replys , im considering building 3 panels , each panel having 36 cells so should be about 16 volts each and about 40 watts each i think :?: and using them to charge 2 x 85 ah batteries . the missus likes her telly and it could easily be on for 4 hrs a day . im hoping these would be enough to keep the batteries reasonabally topped up in the uk sunlight .
cheers
kenny+stella


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## Anonymous (Nov 10, 2000)

Hi Kenny.



theflyingscot said:


> hi guys
> thanks again for the replys , im considering building 3 panels ,


Did you decide on the US supplier or have you found another source?
Doug...


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## 88726 (May 9, 2005)

hi doug
im looking into a uk source first . there seems to be a few in u.s. but dont want to go overseas as the duty may overprice the project .
cheers
kenny+stella


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## 88726 (May 9, 2005)

hi guys
found my uk supply of high ma rated cells now for the next challenge figuring out the wiring of these diodes to overcome george's shading problem .


The bypass diode, used to protect shaded modules in high voltage 
arrays, is connected reverse bias and in parallel across the output 
terminals of each and every module. A 
blocking diode prevents the battery discharging through the modules 
at night. The blocking diode is inserted, forward bias and in series 
with the positive power lead from the PV module, subarray, or array.

gonna have to figure this one out :?: :? :? :? 

cheers
kenny+stella


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## spykal (May 9, 2005)

Hi Kenny

Firstly what you doin' up this late?

I am following your thread with interest, I don't really need a solar panel but constructing one does sound like a good project so I may have a go at it :wink: 

Will you share with us your supplier of parts and keep us in touch with your progress as you go along.

Ages ago on this forum or elsewhere I read a really good report of someone doing the same thing...I only wish I could find it now, it would have helped you immensely. I will keep looking...or does anyone else remember seeing it?

Best of luck with the project.

Mike


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## 88724 (May 9, 2005)

Hi 

Just wondering, but why build your own at all? It cannot be financial as the parts to complete are not that much cheaper, Factor in a notional cost for your time to complete (it will take some consideral time and effort to achieve a professional looking result) and then allow for fact that you have no Guarantee......... with a pro made panel you have 15 to 20 year Guarantee

So from a purely financial point of view its not worth the effort.

Is it better than a pro version? ie sometimes building something for youself could be a much better end product. That would have to be a no too.

Pure joy of doing it yourself?

Just wondereing

George


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## 88726 (May 9, 2005)

hi guys

mike : must have finally gone to bed , didn't read youre reply till this morning . once i start searching the net for stuff time does fly :lol: :lol: 
think youre talking about a post from a member called veralin who put some pics in the gallery and purchased an e book . doug sent me a link . i will pm you about supplies once ive got mine :wink: 


george : i will definately save a few hundered pounds compared to buying these from a dealer guaranteed. then theres the hobby factor , its educational and the fact that i actually like doing this type of stuff .


cheers
kenny+stella


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## 88724 (May 9, 2005)

Hi Kenny

As an hobby fair enough but you can beat £2 per nominal watt? and this is top Amorphos tecnology (even paying yourself at minimum wage? with a 20 year guarantee?

I did look into this a bit back and could not justify the price.

Fun to do, sense of achievement and all that.

George


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## DABurleigh (May 9, 2005)

Don't think it is earlier in the thread but IIRC from when I last looked at solar cell technology, amorphous is less efficient in full sunshine, so it requires a larger array for a given wattage maximum output, but this maximum output rolls off less than crystalline in cloudy conditions, so possibly amorphous is better for UK use. I don't recall the shadowing discriminator, this is usually down to how the cells are connected, but it may simply be a side effect of this same roll-off characteristic.

The thing that swayed me to crystalline, though, was the much poorer life of amorphous. Think of plasma TV screens as an analogy, which also have life issues.

It is a shame so many things are more expensive to DIY than buy outright, but at least such projects are rewarding. Researching, specifying, component buying, building and commissioning this silent but (then) reasonably powerful PC was the same. Time-consuming, but stimulating and satisfying. Just ended up paying through the nose for it :-(

However the DIY projects that annoy me are repair ones. I've just finished repairing a toaster which failed to lock down. It took me literally hours, mainly in figuring out how to take it apart without wrecking it. They are designed as cheap consumable items nowadays. I could have bought a passable toaster from Argos for just over £5, but it would have hurt to have thrown out something which was still 99% perfect. Fixing a leaking electric kettle was the same. Wife thinks I'm nuts. Is it a man thing?

Dave


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## 88726 (May 9, 2005)

hi guys
i chose monocrystaline as : the output power i wanted was going to create a very large panel with amorphous . i want a compact panel with high output as my motorhomes got to carry it around . cost with monocrystaline was a lot cheaper . and they apparently work very well in the u.k.

ps : just ordered my diodes !  

cheers
kenny+stella


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## 88724 (May 9, 2005)

They only work OK in UK due to heat (more specifically lack of it)

Area for area an Amorphos panel is ALWAYS going to perform better, if they get hot they go downhill, so any decent sunshine and the powers down, same with slightest shadow. Amorphos is better in all conditions

They are cheaper for a reason, they just are not as good. When they send a panel into space its Uni Solar (amorphos)


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## 88726 (May 9, 2005)

hi george
couldnt find them at usable price in the uk and watt for watt they were too big for me . sorry mate . many thanks for the reply's though . in fact huge thanks to all for the replys ! :wink: :wink: :wink: 

just had a look at my leisure batt and it dosn't say how many ah it is so im in difficulty in matching it up with another to start a bank , unless somebody knows how to do it with a multimeter or something .

any ideas ?
cheers
kenny+stella


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## 88724 (May 9, 2005)

Give me L X W X H and weight If poss

But its not a good idea to add a new and old battery togethor, both will suffer in the long run.

I had a game sorting through a stack of batteries to get 10 matched serially off the line.

In the long run getting two matched new is the best, use the present as a spare.

Another tip, to equalise charging and discharge, take positive connection from battery one and the negative from battery two.


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## 88726 (May 9, 2005)

hi george
i managed to get the rating from some identifying numbers by typing them into google , i did have to remove it as the numbers were on the back , typical . the batt was new when we got the van so its not even 6 mths old and hardly used so im going to keep it for now but i know what youre saying . thanks for the connection tip i will use it .
cheers
kenny+stella


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