solar panels

[deletedaccount]

I may well have found 68w uni-solar stick on panels for 1/2 price. I'll post updates if i do.

[WotEver]

I may well have found 68w uni-solar stick on panels for 1/2 price. I'll post updates if i do.

What has this to do with Triumphs? Oh, sorry, you're actually on-topic. My mistake.

 

[Trilby Tim]

I may well have found 68w uni-solar stick on panels for 1/2 price. I'll post updates if i do.

Let us know if you do, I'm looking for some of those!

[Evo]

Not so sunny today and not such a good result...down to 12.7 on the reg readout...hmm. What I have to remember is with no panels I would be well into the 11's by now and soon have a flashing light on the fridge. They are nearly there, but just not quite....Thats OK, I didn't really expect them to be, they are doing what I want. I turned the fridge off tonight and I expect to see fully charged batteries tomorrow night...that'll do for me.

[Evo]

My god I made the right decision to buy Solar panels this year didn't I...bl***dy hell...

 

Well the old cheapo's have been doing OK....lots of lovely charge and the fridge is on all the time at the moment....allthough we did take the boat out Sunday so helped out the panels a bit. I'm dead impressed with them, but I wont be drilling any holes in my roof to fit them permanently. I'll see how long they last and when they are shabby or knackered and I have had what I consider my moneys worth Ilm off for one of these..!!

ebay panel

[Phil Ambrose]

Well, all i can say is...if you reckon you can run a fridge off of a solar panel...thats some solar panel..neah thats a real 'die hard with a vengeance' solar panel..blimey even my mega big alternator has trouble with the fridge. My panels wont even light up a bulb...I was going to make a fancy bracket and stuff for them, but going on their performance so far I might just let the wind flip them into the cut. They really are the most disappointing things I have ever invested in...LOAD OF CRAP.

 

You have to invest in good gear to get results. We have 5 X 100 watt panels and run a 12v undercounter fridge and a 12v undercounter freezer 24/7 plus all the usual bits and we dont need a charger till the shorter days set in.

 

Phil

[ymu]

I feel that Solar panels still have some way to go before they offered good "bangs per buck" ( AKA good Watts per Wedge)

Compared to mains electricity, no. But burning diesel/petrol to generate electricity is much more expensive, so I'd think a good set of panels would pay for themselves pretty quickly on a boat. Even if you're not on board that frequently, keeping the batteries topped up and in service is worth a fair bit.

 

Definitely on my wish list. Thinking about forking out for stick-down amorphous panels. The extra size of them doesn't really matter when you can walk on them. But ... does anyone know if it causes problems when it comes to painting the boat? Or do you just forget about painting under them ever again?

[dor]

I'm very impressed with what my 100W panel does. It's mounted flat, so effectively only about 65W, but it keeps up with my fridge and laptop running off the inverter on sunny days. It also means that when I come to the boat on a thursday or friday, the batteries are fully charged, when before they were never getting a full charge as we never went far enough at weekends. If it saves one set of batteries it has practically paid for itself. Also means I'm not having to run the engine for an hour or two in the day.

[Nickhlx]

Has anyone actually MADE their own solar panels, from solar cells ? I.e. soldered the cells together and installed in a suitable box ?

Being the practical sort, its something that really appeals to me..

 

I have been Googling for the panels and invariably the price per watt is approx 1/4 of the pre-fab'd panel.

( e.g. http://cgi.ebay.co.uk/SOLAR-CELLS-6x6-100p...=item3caddb6037

 

Buying slightly less than perfect cells ( chips on edges) result in them being cheaper than grade A cells, with minimal reduction on power output, and the 6" by 6" cells ( about 36 needed for a "nominal 12 volt" charging system) produce about 4 watts each ( at 0.5 volts) and cost about 62.5p each - and cheaper in larger quantities.

 

 

So, making your own takes the cost per watt down from around £2.30 per watt to around 60p per watt for the cells ( really !!). I am going to make a small one (20watts) with an introductory offer kit for about £45 which comes with instructions/tips CD to get the experience and a feel for it all, then maybe make a 160 watt panel for the boat, and a kilowatt or two for the house. I am still looking into the grants and "selling back to the grid" aspects, but apparently an up to £1500 grant is available for a solar installation, but it does seem to stack up over the medium and longer term..... I think to get the FIT and grants though you have to have all professionally installed, so there will be quite an investment, and the payback / breakeven period will be in the order of 6 years, but looking at the savings (and income) thereafter is significant - better than some "conventional investments" in the city !

 

Nick

Edited July 1, 2010 by Nickhlx

[Bobbybass]

I met a guy at Watford locks 2 years back who was a professor ( I was told) and taught physics....

His entire roof was covered in large cells and he told me he had a ton of 2 volt batteries in the bottom of the boat...and a control system he had developed himself.

Claimed he was reading 1 Kw/hour on sunny days.

He did tell me.....that it is important that solar cells have good free air ventialtion around the back and that 'stick down' types were at a serious compromise..although convenient for boat use.

 

I bought 2 x 120 watt panels and a controller last year.....and have been very pleased.

Its difficult to quantify figures......but I do know that I moored at Thrupp for 5 days last year ...in the sun...and had to run the engine for 2 hours in that period...running fridge and satellite/ TV. It is also excellent that I can leave the boat for months and the batteries are full when I return.

As I say...it is difficult to quatify...but when I go to bed at night batteries are about 12.5 volts (summer temperature) ..and run the fridge all night..

If I get up at 8am..they have been charging since the sun came up...and I can run Satellite/TV for an hour and the Eberspacher (for hot water)..whcih takes quite a 'kick' to light up and run...my electric towel rail (36watts/240 volts) and the fridge...and after an hour It's still reading 12.5 / 12.6 volts....

 

I can say..that I am pleased with them.

 

Bob

[Nickhlx]

I think that solar panels are now at the price point where its definitely viable if you can (and are prepared) to make them yourself for most people. Of course there will always be people who can throw money at any "problem" and may have had panels for some time, but now panels are typically at around 16.5% efficient, and around £2-40 per watt in "ready to go" form and maybe less than a pound per watt if you can D-I-Y them, its a nice little project to do.

 

The heating issue is that the cell output drops off quite rapidly with increase in temperature, so its important to try to keep the cells cool.

 

Perhaps paint them white ?

 

Nick

[Chris Pink]

Has anyone actually MADE their own solar panels, from solar cells ? I.e. soldered the cells together and installed in a suitable box ?

Being the practical sort, its something that really appeals to me..

 

I have been Googling for the panels and invariably the price per watt is approx 1/4 of the pre-fab'd panel.

( e.g. http://cgi.ebay.co.uk/SOLAR-CELLS-6x6-100p...=item3caddb6037

 

hmmm....

 

the rated voltage is 0.5V - does this mean you'll have to string 36 in series to get 18V, thus make the array of 100 around 12W?

 

The 400W in the listing seems a mite disingenuous to me.

 

caveat emptor

[Nickhlx]

hmmm....

 

the rated voltage is 0.5V - does this mean you'll have to string 36 in series to get 18V, thus make the array of 100 around 12W?

 

The 400W in the listing seems a mite disingenuous to me.

 

caveat emptor

 

 

Yes - most panels for a 12 volt system have approx 36 cells in series to make the 18 volts needed for enough "headoom " to charge a nominal 12 volt battery. That is approx 1/2 volt for the (Schottky) blocking diode drop, and 3 volts for the regulator, leaving up to 14.5 volts available for the battery.

 

Each panel is producing about 0.5 to 0.6 volts, at approx 8.0 amps which is the 4 watts - 36 in series will be the 18 volts at 8 amps,

less the 1/2 volt diode drop, so about 17.5 volts at 8 amps is about 140 watts...

 

String 100 in series and you get about 50 volts at 8 amps or about 400 watts. Panel size is limited by practical handling ...

 

A MPPT controller which can handle the voltage and current, will be "transforming" this to around 14.5 volts at around 27 amps. I think these would cost around £150 ( for this one http://cgi.ebay.co.uk/Morningstar-Sunsaver...=item20b162ec36 ) which can handle up to 75 volts and 15 amps, and output is for a nominal 24 volt battery system.

 

I can see the way through this to make it a project.... I think when these sort of facts become more well known, then the doubts, the magic and mystique etc, will evaporate, panels will further reduce in cost and there will be a lot more in use.

 

At the moment, until I have made one or two for myself, I am reserving judgement, but won't be too surprised if I will be feeling "ripped off" by current panel prices in a month or so. A few hours work will result in the materials cost of a panel of around 140 watts being around £140 i.e. a pound a watt. The rest must be profit for the manufacturers, as they obviously need to make a profit.

Bigger panels will be cheaper.

 

Nick

Edited July 1, 2010 by Nickhlx

[WotEver]

the rated voltage is 0.5V - does this mean you'll have to string 36 in series to get 18V, thus make the array of 100 around 12W?

100 x 4 watt panels = 400 watts in whatever configuration you wire them.

 

Tony

Edited July 1, 2010 by WotEver

[Justme]

I am still looking into the grants and "selling back to the grid" aspects, but apparently an up to £1500 grant is available for a solar installation, but it does seem to stack up over the medium and longer term..... I think to get the FIT and grants though you have to have all professionally installed, so there will be quite an investment, and the payback / breakeven period will be in the order of 6 years, but looking at the savings (and income) thereafter is significant - better than some "conventional investments" in the city !

 

Nick

 

Domestic grants have stopped.

There was a small overlap that allowed you to get both but thats ended too.

FITs need approved kit & install

Payback would never be 6 years, more like 10-12.

 

When you have added in the cost of the toughened glass front & frame does making your own still add up?

 

 

 

If you scrimp on the frame / glass will they last as long as a made panel?

[Nickhlx]

Domestic grants have stopped.

There was a small overlap that allowed you to get both but thats ended too.

FITs need approved kit & install

Payback would never be 6 years, more like 10-12.

 

When you have added in the cost of the toughened glass front & frame does making your own still add up?

 

 

 

If you scrimp on the frame / glass will they last as long as a made panel?

 

Still some questions still to be researched

Grants only started on 1st April 2010 on one site I looked at... so puzzled by "no more grants" comment

Plexiglass and Aluminium frames seems to be the norm on recent panels...

I am looking at panels for two purposes - one type for "me and the boat", and one type for the house,

so full commercial specs (prices) may well not be applicable anyway.

Thanks for the tips though,

Nick

[Justme]

Which site? Grants as in money for doing it stopped.

 

FITs for making it started on 1st April 2010.

 

There are lots of sites still telling you that grants are available.

 

Plexiglas will cloud over (you would also need to check the transmission of the correct light wavelengths, use glass. might cost more but you will only do it once.

[nb Innisfree]

Trouble is when panels become cheap the next (expensive) generation which will be more efficient and therefore smaller will be available which will make it practical to use them on a nb. At the moment they are not efficient and small enough to be practical even if very cheap. Early days yet.

[Nickhlx]

Trouble is when panels become cheap the next (expensive) generation which will be more efficient and therefore smaller will be available which will make it practical to use them on a nb. At the moment they are not efficient and small enough to be practical even if very cheap. Early days yet.

 

 

Indeed ! - already I have discovered that cells with about 40% efficiency are "close" which will approximately halve the collector size for a given output. They achieve this by concentrating the solar energy with micro lenses, thereby managing to extract more energy from higher intensity.

 

Nick

[Sunstore Solar]

Hi guys

 

I have been reading up on your posts and thought i would just introduce myself to you.

 

My name is Tom and I am the owner of a company called SunStore. I'm not here to sell but in fact, to learn. We have been selling panels for many years and it continues to impress me to the variety of uses they end up in. We have undertaken hundreds of tests with loads of equipment to ensure we know as much as possible. That said, its never enough.

 

I'll leave it at that but I am happy to help you out on a completely impartial basis where ever I can.

[gilby]

Compared to mains electricity, no. But burning diesel/petrol to generate electricity is much more expensive, so I'd think a good set of panels would pay for themselves pretty quickly on a boat. Even if you're not on board that frequently, keeping the batteries topped up and in service is worth a fair bit.

 

Definitely on my wish list. Thinking about forking out for stick-down amorphous panels. The extra size of them doesn't really matter when you can walk on them. But ... does anyone know if it causes problems when it comes to painting the boat? Or do you just forget about painting under them ever again?

 

We siliconed and bolted three semi flexable solara panels. Took them off last year to repaint and found that the paint had 'sweated'. The paint just scrapped off to bare metal with no effort at all!

When we refitted them we used some cork strips (flooring expansion) to raise the panels off the roof solve this. Adding this ventelation I think will help keep the panel temp down too. (Might test that tomorrow by comparing temp' with the neighbours panels). Can still step on the panels if that's of importance to you.

[ymu]

Cheers!