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How to boost any solar panel output by 75%Here''s a really cost effective and simple way to get 75% more power from any ordinary solar panel. The theory: Most of the time a solar panel is working well below peak power, on hazy days and when the sun is lower in the sky, early morning, late afternoon for example. The light levels are just not high enough, so to boost the light level I tried aligning a mirror to reflect more light onto my solar panel. It worked really well and after a bit of experimentation I found that placing a mirror at least twice the size of the solar panel on the ground in front of the panel could boost the output by as much as 75%.  Using a bigger mirror can reflect light onto your panel over a longer period during the day so you don't need to track the sun, just face your panel and mirror due south. The practise: I bought a really cheap solar panel for £10.00 to test this idea, below are some pictures showing what I did and the meter readings just to show that it really does work. Pictured below is the 1.5w solar panel facing south just placed on a wood board to stop the grass shading the panel. The meter is showing 0.07 amps, that's approximately 0.84 watts, it's late October and even on a very sunny day the panel is only producing just over half it''s peak power.  In the picture below you can see how the mirror reflects light onto the solar panel. The panel produced 0.12 amps, about 1.44 watts, very close to the maximum rated output for this panel.  If you use a large mirror there is no need to align it to reflect light onto the solar panel just drop it on the ground in front of the panel for an instant 75% power boost. Conclusions: This is probably one of the cheapest and easiest ways to boost the power of a small solar panel, but this method does have some limitations:
Doing the math: Currently solar panels cost around £4.00 per watt so that makes a 20w panel about £80.00. A 75% increase in power is the equivalent of a 35w solar panel, which would cost about £140.00, that''s a saving of £60.00. Or a cost per watt of around £2.30 OK you have to find a mirror or polished sheet of metal but still it's a huge saving. Developing a low cost solar panel tracking system would further boost the efficiency but getting more light onto a solar panel on an overcast day could have the most potential benefit. I'll continue to test a few different panels with different set-ups and post the results below. |
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| [ comments 29 ] |
| posted by Colin | 22/12/2007 08:13:35 |
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| Hi Paul I see you`re a mad scientist type too :) From the figures i guess its a 12v panel, i wonder if theres any merit in trying to lose the excess heat before it hits the panel? Something like a small aquarium filled with water to absorb the longwave radiation as a test? I think you`ll likely lose some light intensity but on the flipside you might gain some warm water :) | |
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| posted by Colin | 24/12/2007 04:07:44 |
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| With hindsight i think arranging the panels next to a shallow pool may be the solution. In theory, you should get reflection without the heat. Probably have to wait until next year to get some sun though :) | |
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| posted by Brian, Michigan | 01/02/2008 22:40:18 |
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| How about a combined heat and power application, using some of your DC to run a pump that takes water through a series of loops around the back of the PV, then dumps it into your hot water tank (parhaps using a small inline tank with a heat exchanger). They make stuff like this, but it's not used much yet. Cooling the panels isn't just good for longevity, you get a higher voltage and thus more power when the cells are colder. May be a bit more involved than you'd want to get though... | |
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| posted by me | |
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| anyone tried magnifcation and or spectrum filtration? btw cooling systems of somekind are a must have if you truely want to live off the grid | |
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| posted by Admin | 31/10/2008 03:10:15 |
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| Just found this great page on building a solar concetrator using an old sky dish.Click here | |
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| posted by James | 08/03/2009 14:46:31 |
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| Heating will certainly damage the panel. I bought some cheap 20W panels on eBay for £2.75 per watt but they are factory seconds so the don't give the advertised wattage. Computer modders have been cooling their over-clocked computers for many years. I wonder if something similar can help cool PV cells. The best for now is to use mirrors on overcast days and be greatful on sunny days without mirrors. | |
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| posted by SKGiven | 18/06/2009 15:28:27 |
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| You might want to try using a self made polarised mirror (sun glasses technology) - If you can get a strip of such plastic-like material and put it over a mirror? I know you can get polarised windows, which let most of the light in when it is cloudy, but relatively less when it is bright. In theory this should stabilise both the input of light and output of electric, thus facilitating the solar systems longevity (panel, regulator...): When it gets too bright, the mirror will darken and less light will hit the panel from the mirror, so it will not overheat, and will last longer! | |
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| posted by mike | 18/07/2009 04:27:34 |
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| i read that it limited lifespan when using mirrors. But maby watercooled with mirrors? | |
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| posted by Dan | 31/08/2009 16:29:09 |
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| Perhaps just using some cheap shiny white plastic material would be better. I guess it would be similar to using photovoltaic panels in a snow covered environment which reflects loads of diffuse light, remember snow blindness etc. | |
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| posted by cobe | 08/09/2009 15:18:10 |
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| you could place the solar panel in cooking oil as oil dosnt conduct electricity but is very good as an insulator | |
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| posted by lee | 17/09/2009 13:48:47 |
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| The diagram shows the sun giving off light in a different angle to the mirror than to the pv. In actual fact it is so far away from earth it arrives in parallel lines to both. This will affect your ideal positioning of the mirror. I read a report on electronicspoint website of someone spraying water over his panels and gaining 10% by cooling | |
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| posted by Fergus | 26/10/2009 11:53:01 |
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| Great idea. I understand that PVs can overheat, reducing their performance and longevity, but... here in the UK we have less than half the insolation than southern Spain. If PV manufacturers recommend the use of their panels near the equator without mirrors, surely it stands to reason that using them in the UK with a mirror that increases light onto the panels by up to 100% would work without damage. Or do installations in hotter countries gnerally include overheat protection? | |
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| posted by mamos | 08/11/2009 23:12:54 |
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| What about a heatsink of some sort on the back of the panel. For a fantastically simple yet effective sun tracking system check out DIY 12 volt solar power by Michel Daniek The man is a genius mamos | |
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| posted by thewindmillman | 17/11/2009 16:15:03 |
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| i have done this expirement and got similar results i also have found that if the panel is kept coolby running cold water over it lightly it power producing abilities again rise so0 good on you sir thought i was the last nutter on the planet of you use an old satalite dish rapped in aluminium foil as a parabolick mirror you can also use like an inverted magnifing glas on to solar panel also email me your mad enough to land on the free electric for the planet together we may do it tomorrow regards thewindmillman | |
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| posted by cyprelda | 07/12/2009 23:49:24 |
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| Get the government or private body to send up a sattelite in a set position with reflecting material then everyone would benefit. | |
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| posted by Russell | 06/01/2010 10:17:44 |
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| Even if you have your panels on your roof you can still use a reflector to increase sunlight onto the panels. I use a vertical reflector at the back of my flat plate solar hotwater system to increase sunlight onto the plate, especially in winter. When I get some PVs installed soon, I may do something similar, but only in the cooler six months of the year. I also am thinking of using an oscillating sprinkler to keep the panels cool in summer, which here in western Sydney can reach 35c ambient temperatures, which equates to a panel temperature of 60+ degrees. | |
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| posted by myamberdog | 06/01/2010 20:26:10 |
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| I have a different problem - I have 2 of my 20 basically flat angled panels shaded by a new LARGER air-conditioner that was installed last year (panels being on the north side of course) and i noticed the daily WINTER production went from 7 kwh to a little over 3 kwh. My idea was to build a vertical mirrored flat surface, behind and at a right angle to the panels. I was going to put mylar over plywood???X!!! And i would take it away in the spring when the sun clears the A/C obstacle. My dealer is concerned about panel burnout, too, which would invalidate the 25 year warrantee I'm about 6 years in to. I also live in Palm Springs, CA so have to definitely be careful about heat buildup - what does anybody think? | |
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| posted by myamberdog | 06/01/2010 20:30:53 |
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| ......lol.....how funny Russell you would post this at my exact time of posting....although mine was for PV's yours was the solar water heating panels......we get 110 Fahrenheit easily for a least a couple months in our summers and i've never had less than 15-16 kwh produced each day...and as far as i know, no heat problems.... | |
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| posted by Admin | 06/01/2010 20:49:46 |
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| Sounds like a great idea myamberdog, as far as heat goes I would think as long as you don't exceed the max output of the panel heat shouldn't be a problem. I honestly can't see any reason why a panel would be damaged by a little extra heat. | |
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| posted by daan | 16/01/2010 14:23:05 |
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| How about using a moving mirror, that directs the sunlight towards the pv panel, without ever shading it and to simply beam the ligth somewhere else once the PV panel becomes overheated?? | |
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| posted by daan | 16/01/2010 16:03:55 |
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| Hi, great ideas. Why not make an Arduino based aiming mirror that concentrates sun at the panel. When the sun is to strong it takes the beam of the panel. | |
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| posted by pieter | 24/01/2010 20:42:51 |
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| Has anyone done some study, as to what temperature is too high, how much temp the mirrors add, and at what rate of temperature, would say, a panel in Canada run at. It does make sense to take away additional heating in mid-summer, but after that it's hard to believe there would be an issue. | |
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| posted by Russell | 22/02/2010 11:11:40 |
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| Most PV panels ratings are stated at a panel temperature of 25c, in real life most panels will operate at surface temperature well above this. I have seen youtube sites where the panel surface temp was at 66c with an ambient temp of 38c. My feeling is that the panels will produce a lot more power if we can keep their surface temp as low as possible in the real world. | |
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| posted by daan | 26/02/2010 17:24:10 |
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| I live in the netherlands and high temperature is hardly the issue. I think it is very interesting to boost the amount of light on the panel. I will make some prototypes to test the concept. There must be data though about maximum operation temperatures | |
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| posted by Eric Johnston | 08/03/2010 03:18:07 |
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| The original results are flawed since Power is Volts*Amps and 0.07 amps is only 0.84 watts _IF_ the voltage is 12 volts, but at the shunt resistance of a meter in 'current' mode (usually < 1 ohm) the voltage will NOT be 12 volts, but probably down around 0.5 volts. Please refer to wikipedia for information on 'maximum power point' load for a solar cell. I did an experiment and checked the voltage with and without mirrors at up to 12 load resistance settings (using a decade box) and found that one mirror of about 3x the width of the solar cell at an angle to match the mirror's reflection to the solar cell area (about 20 degrees) only gave about 25% increase at the max. power point for each light level. Better than nothing since mirrors are cheap, but most PV installationss use MPP trackers so can only benefit so much. With twice as much mirrors, I didn't see ANY increase in the maxiumum power, but that was because the temperature went so high. With water cooling (PV thermal hybrid) it might be possible to use more mirrors. | |
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| posted by daan | 12/04/2010 12:17:06 |
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| Hi. I think we need much more data and testing to completely understand this. I will soon do this. I made a design for a flat mirror based product that can actually fit on a roof. I wonder what you think of zininzelfdoen.ning.com/forum/topics/solarrib-a-design-based-on | |
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| posted by Dave North | 14/05/2010 19:47:05 |
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| I want to fit a pv cell to a narrowboat (canal boat). For reasons of practicality it will have to be mounted flat on the roof, but maybe I can boost output with a mirror which folds down flat when not in use. Comments? | |
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| posted by James | 20/06/2010 16:45:49 |
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| I have placed copper tubing on the back side of PV panel to extract the heat. When I replace my hot water heater I kept the old one. I use the old hot water heater in series with the new one. I use the panel to preheat the water in the old hot water heater. I am getting 380 watts from a 160 watt solar panel for 6 hours a day plus the hot water. with all this it will still take 2 to 3 years to recope my investment. | |
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