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Author Topic: 2 Watts from an old 2N3055 as a solarcell ?  (Read 80034 times)

hartiberlin

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2 Watts from an old 2N3055 as a solarcell ?
« on: June 04, 2005, 07:34:25 PM »
Hi All,
I just found a statement, how a 2N3055 can be used as a solarcell.
Here:
http://www.fieldlines.com/comments/2005/5/3/205028/6819/4#4
is stated:

There is one easy way to do it !
I once purchased a hand full of 2N3055 power transistors at an electronics surplus store. Price was perhaps 25 cents each. I carefully cut the top off one of them (TO-3 can), exposing the die. I obtained a cheap magnifying glass about 6 inches in diameter, connected an ammeter to the collector and base leads and used the magnifying glass to focus the sun on the chip. It produced in excess of 4 amps ! In a circuit you would get best power at perhaps .5V and 3 amps so you would have to put a few of them in series to do anything useful.

Did somebody try something like this ?
Is it for real, that you get 0.5 Volts and up to 4 Amperes ?

But probably you would cook pretty soon the silizium, right ?
What will you get at a cloudy day ?

Regards, Stefan.

terry5732

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Re: 2 Watts from an old 2N3055 as a solarcell ?
« Reply #1 on: June 05, 2005, 04:42:01 AM »
Is it the light or would heat work - try soldering iron.

Vorg

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Re: 2 Watts from an old 2N3055 as a solarcell ?
« Reply #2 on: June 13, 2005, 02:20:54 PM »
Out here focusing tha 6" lens  incenerates stuff. Don't think it would last long.

Walter Hofmann

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Re: 2 Watts from an old 2N3055 as a solarcell ?
« Reply #3 on: June 13, 2005, 10:52:44 PM »
hi all
I used a old camera lens from a one way camera it did give here in foridas sunlight 0.6V and a wopping 5 amps at total focus. Theheat generated with this lense is enough to come to around 600 deg F but if there is a heatsink about 4 X 4 Inches put on the transistor it gets just a bit over 110deg F. even if it is cloudy the output still runs on 1,6 to 2 Amp
there is a loss of about 25 to 40 % if a couple put in series.
greetings
walt

hartiberlin

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Re: 2 Watts from an old 2N3055 as a solarcell ?
« Reply #4 on: June 14, 2005, 12:49:19 AM »
Hi Walt,
thanks for testing this-
When I have more time I will also look for some old
2N3055 I still have lying around somewhere.

Where did you connect the lead, between collector and emitter ?

Regards, Stefan.

prometheus_effect

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Re: 2 Watts from an old 2N3055 as a solarcell ?
« Reply #5 on: June 14, 2005, 01:49:25 AM »
Hi Guys,

Some solar data:

Irridation of 1,000w/m^2 (Max surface level). Probably better to use 900w/m^2.

6" dia lens or 150mm = 0.01767m^2 area * 900w/m^2 = 15.9 watts input to transistor (not including lens transmission losses of about 10%)

Irridation efficiency:

0.5v @ 3a = 1.5w =? ?9.4%
0.5v @ 4a = 2.0w = 12.6%
0.5v @ 5a = 2.5w = 15.7%

Power loss for silicon is about 0.5% per degree C temp rise so good heat sinking is important. Heat sink to about twice the lens area. Suggest you use at least 4mm thick aluminum and use a good heat sink paste between the transistor and the heat sink.

So heat load = 15.9w (solar input) * 0.9 (lens efficiency) * (1 - .126 (efficiency @ 4a)) = 12.5 watts to heat sink at no more than 10C above ambient for good cell efficiency.

For the lens I suggest you use a rigid acrylic Fresnel lense as they have lower losses (about 92 - 93% efficiency).

To get the best efficiency adjust the distance between the transistor and the lens until the bright image of the sun just coveres the silicon of the transistor. There is no need for the image to be focused but just to fully illuminate the silicon surface.

Then you need to track.

Commercial solar concentrator cells are available with efficiencies in the 25 - 37% efficiency range. Checkout:
http://www.sunpowercorp.com/html/Products/SPG/conc.html

All the best,
Greg

prometheus_effect

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Re: 2 Watts from an old 2N3055 as a solarcell ?
« Reply #6 on: June 14, 2005, 04:29:05 AM »
Guys,

64 x 2n3055 @ $0.39us each:

http://store.americanmicrosemiconductor.com/2n3055.html?referrer=google&adlink=2N3055_order

At 2.5 w thats $0.156us per peak watt.

With a good 2 axis tracker you can get a conversion ratio of peak watts to annual kWh of about 2,500. So we should produce about 2.5Wp * 2,500 = 6.25 kWh annually. As most homes use around 5 mWh annually you would need about 800 of these transistors tracking the sun.

Using 6" square Fresnel lens we would get about 28% more energy or about 8 kWh annually per unit. Packing the lens and transistors in a 1 yard square panel we would get 6 * 6 = 36 lens / transistors = 290 kwh annually. Then our 5 mWh energy usage would require 17 such panels and we are off the grid.

All the best,
Greg

 


prometheus_effect

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Re: 2 Watts from an old 2N3055 as a solarcell ?
« Reply #7 on: June 14, 2005, 05:17:38 AM »
Guys,

Just so we know what we are talking about here is a photo of a 2n3055 minus the case. Note the die size is about 2.8mm square or about 7.9mm^2.

Now a 150mm (6") square Fresnel lens has a surface area of about 22,500mm^2. The sun (concentration) factor is then 22,500 / 7.9 = 2,848 suns. That is an amazing figure as most leading edge concentrators work at around 500 suns, while commercial ones work closer to 20 - 50 suns.

That you guys are seeing 2 to 3 watts from such a simple setup is truly amazing.

Walter can you please repost your readings, load resistor value, lens data (diameter, focal length, etc), 2n3055 die size, manufacturer, etc.

Thanks,
Greg

Walter Hofmann

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Re: 2 Watts from an old 2N3055 as a solarcell ?
« Reply #8 on: June 14, 2005, 11:21:29 AM »
Guys,

64 x 2n3055 @ $0.39us each:

http://store.americanmicrosemiconductor.com/2n3055.html?referrer=google&adlink=2N3055_order

At 2.5 w thats $0.156us per peak watt.

With a good 2 axis tracker you can get a conversion ratio of peak watts to annual kWh of about 2,500. So we should produce about 2.5Wp * 2,500 = 6.25 kWh annually. As most homes use around 5 mWh annually you would need about 800 of these transistors tracking the sun.

Using 6" square Fresnel lens we would get about 28% more energy or about 8 kWh annually per unit. Packing the lens and transistors in a 1 yard square panel we would get 6 * 6 = 36 lens / transistors = 290 kwh annually. Then our 5 mWh energy usage would require 17 such panels and we are off the grid.

All the best,
Greg

 


Hi greg,
I dont know where you get the average home usage , but I need at my house down in florida with A/C 2,400 SF, two well and 1 pool pump each 1 1/2Hp, septic pump,1,000SF workshop,washer and dryer etc. 18 to 20 KW anually.
greetings
walt

Walter Hofmann

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Re: 2 Watts from an old 2N3055 as a solarcell ?
« Reply #9 on: June 14, 2005, 11:39:58 AM »
Hi stefan,
I honest dont know which I have connected I will check this again because I try both basis - collector and basis - emitter and both did bring out somethings one more then the other.
I also dont know what manufacturer it just sayd 2N3055 on top. I just took of the top (grinding around with cooling)then took off the plastic cover from the die.Th diameter of the camera lens is around 3/4inch dont know and doesnt say the anything about focul lenght,
The current readings are short circuit with a radio shack DVM set to 20 Amp.
Down here you can not use acrylic lenses because they whould not last more then a few hours in the sun then they start to deform due to the heat (up to 200 degr F)
I try 2 and 4 inch magnifier and they whould not bring more but the distence to focus is to far to make something stable, I aslo try one of this cheap reading glasse with 2.75 and at a distance of about 16 inches it brought allready 0.8 Amp short circuit.I do have a few of this trans laying around and if I find the time I will put a smal array together to see how much it can provide.
But overall in my opinion something like this cannot replace the power for the hole house it only can substitute portions, maybe up to 1kW, for light or so.
greeting
walt

prometheus_effect

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Re: 2 Watts from an old 2N3055 as a solarcell ?
« Reply #10 on: June 15, 2005, 01:46:26 AM »
Hi Walt,

Try connecting the emitter and collector together. That way you get to use both NP junctions (base to emitter and base to collector) to capture photo electrons.

A 3/4" diameter lens would capture about 0.3w of solar energy. Max solar energy at sea level is about 0.1w/sq cm or 0.65w/sq inch.

To calculate power you need to measure both voltage and current. I suggest you try a 4.7, 2.2, 1, 0.47, 0.22 0.1 ohm resistor as the load and plot what you get. The cell voltage produce be around 0.5 - 0.6 volts until it hits the peak power point then drops quite sharply. The peak power point is just before the cell voltage drops sharply. I have attached a typical PV (photovoltaic) IV curve.

Here in Australia a typical house uses around 5,000 to 6,000 kWh annually. Do you know your annual kWh usage?

The company I work for is developing a very innovative solar concentrator and tracking system which should deliver annual kWhs at about 1/2 the cost of traditional fixed flat panels. It is designed to be mounted on domestic roof tops and can even be mounted on north facing roofs to avoid loss of street scape if the home faces south. Reverse the directions for the southern side of the planet.

BTW optical grade acrylic can handle the heat load as it transmits 93% of the light passsing through. Generally glass has higher losses, is much more fragile and weighs more than optical grade acrylic.

Greg

prometheus_effect

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Re: 2 Watts from an old 2N3055 as a solarcell ?
« Reply #11 on: June 15, 2005, 06:40:36 AM »
Guys,

Here are three more examples I found. Note the very much larger die size for the MJ21193 (middle) verus the 2N3055 (left). This transistor (the MJ21193) should really generate some hefty amps.

Greg

Walter Hofmann

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Re: 2 Watts from an old 2N3055 as a solarcell ?
« Reply #12 on: June 15, 2005, 11:35:37 AM »
Hi Walt,

Try connecting the emitter and collector together. That way you get to use both NP junctions (base to emitter and base to collector) to capture photo electrons.

A 3/4" diameter lens would capture about 0.3w of solar energy. Max solar energy at sea level is about 0.1w/sq cm or 0.65w/sq inch.

To calculate power you need to measure both voltage and current. I suggest you try a 4.7, 2.2, 1, 0.47, 0.22 0.1 ohm resistor as the load and plot what you get. The cell voltage produce be around 0.5 - 0.6 volts until it hits the peak power point then drops quite sharply. The peak power point is just before the cell voltage drops sharply. I have attached a typical PV (photovoltaic) IV curve.

Here in Australia a typical house uses around 5,000 to 6,000 kWh annually. Do you know your annual kWh usage?

The company I work for is developing a very innovative solar concentrator and tracking system which should deliver annual kWhs at about 1/2 the cost of traditional fixed flat panels. It is designed to be mounted on domestic roof tops and can even be mounted on north facing roofs to avoid loss of street scape if the home faces south. Reverse the directions for the southern side of the planet.

BTW optical grade acrylic can handle the heat load as it transmits 93% of the light passsing through. Generally glass has higher losses, is much more fragile and weighs more than optical grade acrylic.

Greg
Hi greg,
it was a typo my house needs 15 to 18.000Kw.
You know I am not realy in to the solar scene, because here we got great sun times but there are many month 4month rainy season, 5month hurricane season) where as I have testet there is not enough to run solar cells this test was just for fun and the mentioned currentoutput. Maybe later I will do some more testing.
greetings
walt

2tiger

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Re: 2 Watts from an old 2N3055 as a solarcell ?
« Reply #13 on: August 25, 2005, 12:16:37 PM »
Hi
I?m new in this Forum, and my english is not very good, but I will try my best.

Well I bought 3   2n3055, cut off the tops and connected them in series.
On a sunny day I get 1,47 V and on a very cloudy day 0,82 V out, without magnifying glas.
Then I connected a little motor from an old walkmann to a simple Battery (1,5 V) to messure the current (0,355 A).

So I thought that it woud be no problem for the "transistor-solarcell" to drive the motor....

...but nothing happens!!! 
The voltage breaked down and the Ampmeter displayed 0,005 A.

Is that right?
That the high Amps are only produced by concentrating the light with a magnifying glas?
In that case I will try to get some and try out again.
 



hartiberlin

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Re: 2 Watts from an old 2N3055 as a solarcell ?
« Reply #14 on: August 25, 2005, 12:31:11 PM »
Yes,please try with a magnifiying glas and report again.
Thanks !