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Solid States Devices => Joule Thief => Topic started by: TinselKoala on August 14, 2015, 08:35:07 AM

Title: High Efficiency LED for Joule Thief, etc.
Post by: TinselKoala on August 14, 2015, 08:35:07 AM
Here's something I've been playing around with. It's a high-efficiency LED,  Philips Lumileds MXA7-PW57-H001, coupled with a AP2502 current-sink regulator chip. The AP2502 has 4 current-sink outputs each regulated to sink 20 mA. So over the supply voltage range of 2.9 to 6 volts, it will keep 20 mA current flowing in the LED, per output. I'm only using one output and one LED here. The chip also has an Enable pin which allows PWM modulation of brightness by varying the duty cycle of the voltage applied to the pin. The chip eliminates the need for a power-wasting series resistor to regulate current. The LED is just about the highest efficiency LED available on the market.

The parts were kindly sent to me by a friend.

I'll be doing some more tests with these devices as time goes by. It will be very interesting to see how long a single CR2032 button cell will keep this LED glowing intensely brightly at 20 mA. The LED is actually nowhere near full brightness at 20 mA; at 100 mA it is blindingly bright, obscenely bright. 

http://www.youtube.com/watch?v=BtcF2aMC_ew
http://www.youtube.com/watch?v=X9wxuRZV-Ro

The LEDs and the current-sink chip are available from DigiKey. The LEDs cost about 70 cents US for a single one, or about 10 dollars for 25 of them. The AP2502 is about the same price. These are both surface mount devices. SparkFun sells a breakout board for SOT-23-6 devices for about a dollar each, that will turn the tiny chip into a standard 6-pin DIP footprint.
Title: Re: High Efficiency LED for Joule Thief, etc.
Post by: MarkE on August 14, 2015, 08:55:54 AM
Each of the pins 3, 4, 5, and 6 sink 20mA when pin 1 is high.  The AP2502 is intended to be used as an area back light driver.
Title: Re: High Efficiency LED for Joule Thief, etc.
Post by: TinselKoala on August 14, 2015, 09:05:26 AM
Each of the pins 3, 4, 5, and 6 sink 20mA when pin 1 is high.  The AP2502 is intended to be used as an area back light driver.
So the chip must be operating its output mosfets in the linear region, yes? With Enable tied 100 percent High, the LEDs aren't pulsed, I don't think, so current regulation must be accomplished by the op-amps regulating the voltage to the Gates of the mosfets as the LED supply voltage is varied. Is that right?
Title: Re: High Efficiency LED for Joule Thief, etc.
Post by: MarkE on August 14, 2015, 09:32:01 AM
So the chip must be operating its output mosfets in the linear region, yes? With Enable tied 100 percent High, the LEDs aren't pulsed, I don't think, so current regulation must be accomplished by the op-amps regulating the voltage to the Gates of the mosfets as the LED supply voltage is varied. Is that right?
Yes, that is how the device works.  The idea is that if you have a lithium battery that is nominally 3.6V in a hand-held product, then you get good efficiency by just linear regulating to a white LED that can run on 2.9V.  Most of the time the battery will be between 3.4V and 3.7V giving you 78% - 85% efficiency in a small space at really low cost. 

JT circuits are current sources of sorts so they don't need the additional regulator to protect the LED.  The regulator flattens the flyback voltage down slope, converging rms and average LED current, increasing efficiency.  Depending on the LED parameters and the particular JT design, the regulator can realize increased net efficiency. 

Those cheapy blue oval flash lights from Harbor Freight just use a simple current limiting resistor.  So, they are quite inefficient and the brightness starts dropping sharply in less than an hour.  A current regulator of any kind makes that better.  A high efficiency switching regulator is more ideal.  A pair of those clip-on 1.5V regulators that have been overhyped would work great with the board that you have.  The efficiency after those regulators would be about 180 lumens per Watt.
Title: Re: High Efficiency LED for Joule Thief, etc.
Post by: ramset on August 14, 2015, 01:33:58 PM
Tinsel
A sizzling Topic ATM ...
Think PINK
I am very Happy to see "you" working on this .

https://www.youtube.com/watch?v=ILzWmw53Wwo

http://www.terraspheresystems.com/index.php/news-media/19-news/41-urban-farming-20-no-soil-no-sun
From Above link  I square ft of Vertical farming WILL YIELD 64 head of lettuce per arum, where as 1 square foot of Land farming
?? MAY ??   yield 3 heads per anum.[Ideal conditions]

Establishing Crop yields per square foot against energy required to run the LED's would be wonderful to know ,do they have to run at full power ?
I do understand that PWM would NOT be acceptable for growing crops ,you can trick the eye But not mother nature [thx Brad].
Or would PWM be appropriate for part of the plants 24/7 365 artificial day ??

This is the future.....

Chet K

Title: Re: High Efficiency LED for Joule Thief, etc.
Post by: MarkE on August 14, 2015, 01:50:49 PM
Tinsel
A sizzling Topic ATM ...
Think PINK

https://www.youtube.com/watch?v=ILzWmw53Wwo

http://www.terraspheresystems.com/index.php/news-media/19-news/41-urban-farming-20-no-soil-no-sun
From Above link  I square ft of Vertical farming WILL YIELD 64 head of lettuce per arum, where as 1 square foot of Land farming
?? MAY ??   yield 3 heads per anum.[Ideal conditions]

Establishing Crop yields per square foot against energy required to run the LED's would be wonderful to know ,do they have to run at full power ?
I do understand that PWM would NOT be acceptable for growing crops ,you can trick the eye But not mother nature [thx Brad].
Or would PWM be appropriate for part of the plants 24/7 365 artificial day ??

This is the future.....

Chet K
The reduction in water consumption and transportation requirements are really the big factors.  You can get a feel for the amount of LED power needed by the density of the lighting in the video.
Title: Re: High Efficiency LED for Joule Thief, etc.
Post by: ramset on August 14, 2015, 03:29:15 PM
Typical comments from Big business attempts / failures  in this area have MUCH more to do with Power needs.

it would be much better to Not "feel" the needs and to actually have a grasp on what they are.
Title: Re: High Efficiency LED for Joule Thief, etc.
Post by: MarkE on August 14, 2015, 04:19:07 PM
Typical comments from Big business attempts / failures  in this area have MUCH more to do with Power needs.

it would be much better to Not "feel" the needs and to actually have a grasp on what they are.
Is that too much or too little coffee talking this morning? 

Water requirements translate to energy needs.  Transportation translates to energy needs.  The fruit and vegetable basket for the USA is in a severe drought right now.  Dropping water needs for vegetables by 90% means dropping a lot of the energy requirements.  20% of California's electricity is used moving water through the state.  80% of that water goes to agriculture.  While it would be nice to know the specific power in the lighting the video suggests that it is not that great.
Title: Re: High Efficiency LED for Joule Thief, etc.
Post by: ramset on August 14, 2015, 04:40:31 PM
Probably need a bit more Coffee  :o

  However...
  for clarity Mark E ,
You want me to get a feel for the input power by looking at the light ?

Did I just read that ??? what Forum am I at ????

it says 3 watts on the box !!
------------

Having done some investigations already , the true costs to the facility are more my Concern ATM , not so much transportation infrastructure and similar costs. Water  as outlined in the Link can be diminished to 5% or less of open field farming [so it is not a real cost to the growing facility ]

  As I have already stated the reasons given for "failure" of big business in  these big indoor growing ventures have been underestimating the energy costs to grow healthy crops , NOT trucking and water costs !


I had read from one blogger in China a reference to 30 KW for their PINK LED farm,  however he did not give more specifics except to say that he and his ":partners" in China had increased food export from their indoor Vertical Farm by 1000% in the last four years.
any info which can be provided here would be greatly appreciated.[these things are rapidly becoming trade secrets in some venues]

respectfully
Chet K

Title: Re: High Efficiency LED for Joule Thief, etc.
Post by: MarkE on August 14, 2015, 08:18:37 PM
Probably need a bit more Coffee  :o

  However...
  for clarity Mark E ,
You want me to get a feel for the input power by looking at the light ?

Did I just read that ??? what Forum am I at ????

it says 3 watts on the box !!
------------

Having done some investigations already , the true costs to the facility are more my Concern ATM , not so much transportation infrastructure and similar costs. Water  as outlined in the Link can be diminished to 5% or less of open field farming [so it is not a real cost to the growing facility ]

  As I have already stated the reasons given for "failure" of big business in  these big indoor growing ventures have been underestimating the energy costs to grow healthy crops , NOT trucking and water costs !


I had read from one blogger in China a reference to 30 KW for their PINK LED farm,  however he did not give more specifics except to say that he and his ":partners" in China had increased food export from their indoor Vertical Farm by 1000% in the last four years.
any info which can be provided here would be greatly appreciated.[these things are rapidly becoming trade secrets in some venues]

respectfully
Chet K
If you want hard numbers you will have to dig.  Begin with PPFD.
Title: Re: High Efficiency LED for Joule Thief, etc.
Post by: ramset on August 14, 2015, 08:31:26 PM
Soo
would you care to guess ?? [to the trained yet uncalibrated eye ]

watts per square foot of growing space [for lettuce]
lets see how close you get .

since I will be looking into this with the manufacturer , [Phillips and others]
Title: Re: High Efficiency LED for Joule Thief, etc.
Post by: MarkE on August 14, 2015, 08:47:26 PM
Soo
would you care to guess ?? [to the trained yet uncalibrated eye ]

watts per square foot of growing space [for lettuce]
lets see how close you get .

since I will be looking into this with the manufacturer , [Phillips and others]
A quick survey suggests an upper limit of 600 PPFD for lettuce.  To translate that to Watts you have to go through the efficiency of a particular lamp design.
Title: Re: High Efficiency LED for Joule Thief, etc.
Post by: TinselKoala on August 18, 2015, 06:48:51 AM
I'm presently testing a MXA8-PW30-0000 LED (see data sheet attached below.)
These have a color temperature of 3000K, rather than the 5700K unit
shown in the videos I linked up above.

At 80 mA, just over 3V, straight DC, it's like a tiny sun it is so bright. It leaves purple spot
afterimages, I can't look directly at it, so I have it pointed away, down at the floor. 

It does get perceptibly warm but not enough to need a formal heatsink yet. In a little while
I'll run it up to 100 mA and see if it lasts.

It runs my "perpendupetulum" light powered pendulum quite well, from a foot away from the PV cell.


Title: Re: High Efficiency LED for Joule Thief, etc.
Post by: MarkE on August 18, 2015, 12:52:46 PM
I'm presently testing a MXA8-PW30-0000 LED (see data sheet attached below.)
These have a color temperature of 3000K, rather than the 5700K unit
shown in the videos I linked up above.

At 80 mA, just over 3V, straight DC, it's like a tiny sun it is so bright. It leaves purple spot
afterimages, I can't look directly at it, so I have it pointed away, down at the floor. 

It does get perceptibly warm but not enough to need a formal heatsink yet. In a little while
I'll run it up to 100 mA and see if it lasts.

It runs my "perpendupetulum" light powered pendulum quite well, from a foot away from the PV cell.
Those LEDs are a real treat.
Title: Re: High Efficiency LED for Joule Thief, etc.
Post by: TinselKoala on August 19, 2015, 09:10:48 AM
Here's a surface brightness comparison. The A19 LED bulb in the desklamp is a "60W" equivalent, rated 800 lumens, soft white 2700K "EarthBulb" brand. The test LED is a MXA8-PW40-0000 high-efficiency LED with a 4000K color temperature, running at 95 mA straight DC, held right up in contact with the A19 bulb. The camera image is taken at 1/500 second, f/32, ISO1600, with my Canon Rebel Xti DSLR. To the naked eye the tiny LED is much brighter than the equivalent surface area of the A19 bulb, and the camera tells me the LED is actually overexposed in this image.

Title: Re: High Efficiency LED for Joule Thief, etc.
Post by: MarkE on August 19, 2015, 09:24:03 AM
The amazing efficiency and affordable cost of current generation LEDs is why Ikea recently announced that they are abandoning CFLs for LEDs.  LEDs are only going to get better and cheaper.  Some researchers believe that ~90% electrical to light efficiency will be attainable over the next few years.  That's almost three times better than what's in the stores right now.  That means that it won't be so long before LED lights produce light using only 5% of what higher wattage incandescents they replace and about 3% of what smaller incandescents consume.  (Higher wattage incandescents are more efficient than lower wattage incandescent bulbs.)
Title: Re: High Efficiency LED for Joule Thief, etc.
Post by: TinselKoala on August 19, 2015, 09:25:18 AM
Here's another shot of the same thing but with the camera stopped right down so that the LED is just barely overexposed. Exposure is 1/1000 second, f/36, ISO 200.

Title: Re: High Efficiency LED for Joule Thief, etc.
Post by: TinselKoala on August 19, 2015, 09:40:39 AM
And one more: exposure same as above, but the LED is now a cooler 3000K unit, MXA8-PW30-0000, running at 75 mA DC. This is a better color-temperature match to the 2700K A19 "60 watt" reference bulb. The LED is still slightly overexposed according to the camera!
Title: Re: High Efficiency LED for Joule Thief, etc.
Post by: SoManyWires on August 19, 2015, 11:04:07 PM
And one more: exposure same as above, but the LED is now a cooler 3000K unit, MXA8-PW30-0000, running at 75 mA DC. This is a better color-temperature match to the 2700K A19 "60 watt" reference bulb. The LED is still slightly overexposed according to the camera!

interesting stuff mentioned above and from others.

wonder what power saving can be had by getting LED's operating at 'useable light' levels for as mentioned, growing lettuce.

can a joule thief create a boost in the LED so it becomes more effective for a plant to produce more yield, while not costing as much as if more emitters had to be used to get the same results?

does PWM really prevent the plant from producing more or even the same amounts, over a 12 hour period or a 18 hour period, when compared to not using PWM or a joule thief?

heat sinks make sense too, liquid cooling by placing the heat producing components into a non conductive clear oil / mineral oil that is not affected towards color change by UV light, or would refraction and dispersion of light from the oil and its lens of a container make the lighting less effective at being 'useable light'?

maybe just placing the LED right attached to the inside of the surface of the cooling tank.
suppose a fresnel lens type of refraction could also be scribed onto the tanks lower and side surfaces if that is helpful,
and or making the tank much thinner only at the points where light will be passing through it to prevent the erosion of light.
passive liquid cooling might be most affordable, dampens sound, and eliminates the need for fans or metal heat sinks.

Title: Re: High Efficiency LED for Joule Thief, etc.
Post by: gotoluc on August 19, 2015, 11:23:48 PM
Hi everyone,

if someone would be ready to buy 2 of either style of the below LED Grow lights to be sent to a Joule Thief Guru like TK or LaserSaber so one can be moded and the other kept original in order to test how much power can be saved and still be able to grow a plant hopefully at the rate as the non moded one, that would be of great service.

Box light: http://www.ebay.com/itm/300W-LED-Grow-Light-Hydroponic-Plant-Veg-Flower-Full-Spectrum-Panel-Lamp-/301507617587?hash=item4633412333 (http://www.ebay.com/itm/300W-LED-Grow-Light-Hydroponic-Plant-Veg-Flower-Full-Spectrum-Panel-Lamp-/301507617587?hash=item4633412333)
 or: http://www.ebay.com/itm/MarsHydro-300W-LED-Grow-Light-Full-Spectrum-Panel-Indoor-Medical-Plant-Veg-Bloom-/171620287365 (http://www.ebay.com/itm/MarsHydro-300W-LED-Grow-Light-Full-Spectrum-Panel-Indoor-Medical-Plant-Veg-Bloom-/171620287365)

Strip light: http://www.ebay.com/itm/Waterproof-81w-LED-Grow-Light-Strip-Red-Blue-Bar-Hydroponic-Indoor-Plant-Lamp-/301663638915? (http://www.ebay.com/itm/Waterproof-81w-LED-Grow-Light-Strip-Red-Blue-Bar-Hydroponic-Indoor-Plant-Lamp-/301663638915?)

Please post if you are ready to do this or if you want to stay private send me a PM.

Thanks for your help

Luc
Title: Re: High Efficiency LED for Joule Thief, etc.
Post by: SoManyWires on August 19, 2015, 11:32:57 PM
Hi everyone,

if someone would be ready to buy 2 of either style of the below LED Grow lights to be sent to a Joule Thief Guru like TK or LaserSaber so one can be moded and the other kept original in order to test how much power can be saved and still be able to grow a plant hopefully at the rate as the non moded one, that would be of great service.

Box light: http://www.ebay.com/itm/300W-LED-Grow-Light-Hydroponic-Plant-Veg-Flower-Full-Spectrum-Panel-Lamp-/301507617587?hash=item4633412333 (http://www.ebay.com/itm/300W-LED-Grow-Light-Hydroponic-Plant-Veg-Flower-Full-Spectrum-Panel-Lamp-/301507617587?hash=item4633412333)
 or: http://www.ebay.com/itm/MarsHydro-300W-LED-Grow-Light-Full-Spectrum-Panel-Indoor-Medical-Plant-Veg-Bloom-/171620287365 (http://www.ebay.com/itm/MarsHydro-300W-LED-Grow-Light-Full-Spectrum-Panel-Indoor-Medical-Plant-Veg-Bloom-/171620287365)

Strip light: http://www.ebay.com/itm/Waterproof-81w-LED-Grow-Light-Strip-Red-Blue-Bar-Hydroponic-Indoor-Plant-Lamp-/301663638915? (http://www.ebay.com/itm/Waterproof-81w-LED-Grow-Light-Strip-Red-Blue-Bar-Hydroponic-Indoor-Plant-Lamp-/301663638915?)

Please post if you are ready to do this or if you want to stay private send me a PM.

Thanks for your help

Luc

that is a good idea!

i wonder if different manufacturers or suppliers might allow donating one or two of their panels in place of crowdfunding.
if the results are to be open sourced and are actually useful, there is a opportunity for good marketing PR with sponsorship.
Title: Re: High Efficiency LED for Joule Thief, etc.
Post by: MarkE on August 20, 2015, 05:00:44 AM
interesting stuff mentioned above and from others.

wonder what power saving can be had by getting LED's operating at 'useable light' levels for as mentioned, growing lettuce.

can a joule thief create a boost in the LED so it becomes more effective for a plant to produce more yield, while not costing as much as if more emitters had to be used to get the same results?

does PWM really prevent the plant from producing more or even the same amounts, over a 12 hour period or a 18 hour period, when compared to not using PWM or a joule thief?

heat sinks make sense too, liquid cooling by placing the heat producing components into a non conductive clear oil / mineral oil that is not affected towards color change by UV light, or would refraction and dispersion of light from the oil and its lens of a container make the lighting less effective at being 'useable light'?

maybe just placing the LED right attached to the inside of the surface of the cooling tank.
suppose a fresnel lens type of refraction could also be scribed onto the tanks lower and side surfaces if that is helpful,
and or making the tank much thinner only at the points where light will be passing through it to prevent the erosion of light.
passive liquid cooling might be most affordable, dampens sound, and eliminates the need for fans or metal heat sinks.
High power LEDs are readily mounted on metal core circuit boards that can then be attached to heatinks of any kind:  liquid cooled, heat pipes, simple fins, etc.  The only issue is cost.
Title: Re: High Efficiency LED for Joule Thief, etc.
Post by: MarkE on August 20, 2015, 05:03:30 AM
Hi everyone,

if someone would be ready to buy 2 of either style of the below LED Grow lights to be sent to a Joule Thief Guru like TK or LaserSaber so one can be moded and the other kept original in order to test how much power can be saved and still be able to grow a plant hopefully at the rate as the non moded one, that would be of great service.

Box light: http://www.ebay.com/itm/300W-LED-Grow-Light-Hydroponic-Plant-Veg-Flower-Full-Spectrum-Panel-Lamp-/301507617587?hash=item4633412333 (http://www.ebay.com/itm/300W-LED-Grow-Light-Hydroponic-Plant-Veg-Flower-Full-Spectrum-Panel-Lamp-/301507617587?hash=item4633412333)
 or: http://www.ebay.com/itm/MarsHydro-300W-LED-Grow-Light-Full-Spectrum-Panel-Indoor-Medical-Plant-Veg-Bloom-/171620287365 (http://www.ebay.com/itm/MarsHydro-300W-LED-Grow-Light-Full-Spectrum-Panel-Indoor-Medical-Plant-Veg-Bloom-/171620287365)

Strip light: http://www.ebay.com/itm/Waterproof-81w-LED-Grow-Light-Strip-Red-Blue-Bar-Hydroponic-Indoor-Plant-Lamp-/301663638915? (http://www.ebay.com/itm/Waterproof-81w-LED-Grow-Light-Strip-Red-Blue-Bar-Hydroponic-Indoor-Plant-Lamp-/301663638915?)

Please post if you are ready to do this or if you want to stay private send me a PM.

Thanks for your help

Luc
The purpose and value of a JT is using the last few percent of a battery's capacity.    That is not an issue when a lamp is mains powered.  There are many LED driver circuits that yield well over 90% efficient power conversion to the LEDs that are also relatively inexpensive.
Title: Re: High Efficiency LED for Joule Thief, etc.
Post by: SoManyWires on August 20, 2015, 07:14:01 AM
The purpose and value of a JT is using the last few percent of a battery's capacity.    That is not an issue when a lamp is mains powered.  There are many LED driver circuits that yield well over 90% efficient power conversion to the LEDs that are also relatively inexpensive.

oh right, thankyou for explaining that.
just wondering something else about joule theives,

is it possible for a joule thief to make better use of solar panels if being used for lighting purposes to get more useable light from LED's if no battery/storage was being used?

could one be used to get a car or a electric start mower even to be able to turn over and start the engine successfully if the battery has lost alot of power from lack of use?

would it matter if trying to recharge a capacitor setup, maybe speed up the charging rate for the capacitor from a nearly dead battery?

been thinking about trying to copy (safely of course) a capacitor based car battery replacement that uses a hand turned dynamo crank on the dashboard or a floor pedal to be able recharge the capacitor to start a car, also good for if stranded somewhere, camping.

are there certain types of capacitors better suited to last maybe indefinitely that can handle being around engine heat, and also arctic cold?

Title: Re: High Efficiency LED for Joule Thief, etc.
Post by: MarkE on August 20, 2015, 10:00:35 AM
oh right, thankyou for explaining that.
just wondering something else about joule theives,

is it possible for a joule thief to make better use of solar panels if being used for lighting purposes to get more useable light from LED's if no battery/storage was being used?
A JT is generally not a very efficient power converter.  A JT is good if you are just going to use it with otherwise dead batteries.  Otherwise, you are better off using a high efficiency power converter that gets the most out of the battery whether or not it works below 0.8V.
Quote

could one be used to get a car or a electric start mower even to be able to turn over and start the engine successfully if the battery has lost alot of power from lack of use?
If it was paired with a supercapacitor or another battery, then a voltage boost converter could theoretically be used, but you might have to wait 20 minutes or more to charge the capacitor from the nearly dead car battery.
Quote

would it matter if trying to recharge a capacitor setup, maybe speed up the charging rate for the capacitor from a nearly dead battery?
That is pretty much the idea:  Slowly charge a low impedance device like a capacitor from the low voltage high impedance nearly dead battery, and then get one or two shots to turn over the engine from the charged low impedance capacitor.  There are a number of lithium battery power packs on the market that also serve as jump starters.
Quote

been thinking about trying to copy (safely of course) a capacitor based car battery replacement that uses a hand turned dynamo crank on the dashboard or a floor pedal to be able recharge the capacitor to start a car, also good for if stranded somewhere, camping.
You would be cranking for a long time.  One of those lithium power packs seems a better back-up.
Quote

are there certain types of capacitors better suited to last maybe indefinitely that can handle being around engine heat, and also arctic cold?
Yes, there are.  The trouble is the energy density goes to hell particularly in cold.  If you want to invent something for arctic cold (you can't patent it because I am describing it to you here and Tesla already sort of does this), then build a lithium pack where the cells are packaged in a well insulated container and add some alkaline cells that run heating wires when the unit is needed to bring the lithium cells up above 10C.  Tesla uses coolant to manage the temperature of their Li-ion cells, both to keep them from getting too cold and too hot.  One embarrassing episode for Tesla was a case two years ago where it was so cold that when a customer plugged into 110V the heaters drew more power than the charger provided.  It's not good when hooking up to charge batteries drains them.
Title: Re: High Efficiency LED for Joule Thief, etc.
Post by: Cherryman on August 20, 2015, 01:23:44 PM
Hi everyone,

if someone would be ready to buy 2 of either style of the below LED Grow lights to be sent to a Joule Thief Guru like TK or LaserSaber so one can be moded and the other kept original in order to test how much power can be saved and still be able to grow a plant hopefully at the rate as the non moded one, that would be of great service.

Box light: http://www.ebay.com/itm/300W-LED-Grow-Light-Hydroponic-Plant-Veg-Flower-Full-Spectrum-Panel-Lamp-/301507617587?hash=item4633412333 (http://www.ebay.com/itm/300W-LED-Grow-Light-Hydroponic-Plant-Veg-Flower-Full-Spectrum-Panel-Lamp-/301507617587?hash=item4633412333)
 or: http://www.ebay.com/itm/MarsHydro-300W-LED-Grow-Light-Full-Spectrum-Panel-Indoor-Medical-Plant-Veg-Bloom-/171620287365 (http://www.ebay.com/itm/MarsHydro-300W-LED-Grow-Light-Full-Spectrum-Panel-Indoor-Medical-Plant-Veg-Bloom-/171620287365)

Strip light: http://www.ebay.com/itm/Waterproof-81w-LED-Grow-Light-Strip-Red-Blue-Bar-Hydroponic-Indoor-Plant-Lamp-/301663638915? (http://www.ebay.com/itm/Waterproof-81w-LED-Grow-Light-Strip-Red-Blue-Bar-Hydroponic-Indoor-Plant-Lamp-/301663638915?)

Please post if you are ready to do this or if you want to stay private send me a PM.

Thanks for your help

Luc


Hi GotoLuc,

Those box LED grow light usally use when measured out of the box around 180 Watts  , a frend of mine uses them.

I myself have ordered some 80W grow lights ( from China ) and they use around 43W out of the box.
http://www.aliexpress.com/store/product/2pcs-lot-E27-E40-80W-640Red-160Blue-Hydroponics-Plant-Lighting-85-265V-LED-Grow-Light-free/835980_1699470283.html (http://www.aliexpress.com/store/product/2pcs-lot-E27-E40-80W-640Red-160Blue-Hydroponics-Plant-Lighting-85-265V-LED-Grow-Light-free/835980_1699470283.html)

Just wanted to share the info.  Because i too want my indoor aquaponics be capable of running solar.
Title: Re: High Efficiency LED for Joule Thief, etc.
Post by: TinselKoala on August 20, 2015, 02:25:07 PM
Yes, the issue of interest here is the practical application of the light from these LEDs. Simple illumination is one thing, but there is presently considerable interest in indoor hydroponic farming, using LEDs for plant growth when sunlight isn't available. So here's where what we've learned about LEDs and Joule Thieves starts coming into play.
MarkE is of course right that the standard JT is mostly for allowing use of the residual energy in depleted batteries, or running LEDs from other low-voltage sources. But we've learned from JTs that LEDs can be "overdriven", that is, driven in pulse mode at higher than the nominal continuous DC drive, and can produce even brighter momentary light pulses, so that the LED seems exceptionally bright to the human eye.
So, instead of JTs running at low input voltages, let us consider whether ordinary pulse-width modulation, overdriving the LED for small duty cycles, can produce any effects, like maybe improved yield/power ratios, when used for plant growth. Would there be any efficiency gain, for example, by driving a bank of LEDs at a high frequency 50 percent duty cycle, at higher than normal drive currents (with another bank phased 180 degrees perhaps, so that the plants would see "continuous" light)?
Title: Re: High Efficiency LED for Joule Thief, etc.
Post by: MarkE on August 20, 2015, 02:51:44 PM
Yes, the issue of interest here is the practical application of the light from these LEDs. Simple illumination is one thing, but there is presently considerable interest in indoor hydroponic farming, using LEDs for plant growth when sunlight isn't available. So here's where what we've learned about LEDs and Joule Thieves starts coming into play.
MarkE is of course right that the standard JT is mostly for allowing use of the residual energy in depleted batteries, or running LEDs from other low-voltage sources. But we've learned from JTs that LEDs can be "overdriven", that is, driven in pulse mode at higher than the nominal continuous DC drive, and can produce even brighter momentary light pulses, so that the LED seems exceptionally bright to the human eye.
So, instead of JTs running at low input voltages, let us consider whether ordinary pulse-width modulation, overdriving the LED for small duty cycles, can produce any effects, like maybe improved yield/power ratios, when used for plant growth. Would there be any efficiency gain, for example, by driving a bank of LEDs at a high frequency 50 percent duty cycle, at higher than normal drive currents (with another bank phased 180 degrees perhaps, so that the plants would see "continuous" light)?
Being diodes, the power dissipated by an LED can be approximated as:

PDISSIPATED = DC*VFW*I + DC0.5*I2*RFORWARD
PDISSIPATED = VFW*IAVE + DC0.5*I2*RFORWARD

Since the light output is almost exactly proportional to IAVE, and

PDISSIPATED = K*POUT + DC0.5*IPEAK2*RFORWARD

And since IPEAK = IAVE/DC:

PDISSIPATED = K*POUT + DC-0.5*IAVE2*RFORWARD

So, you want to minimize the term on the right you want DC to be as large as possible:  ideally 1.0.

LEDs can be dimmed by PWM or by setting the current.  TI and Linear Technology took different approaches for different reasons.  TI built parts that varied the current while Linear Technology used PWM.  TI argued for maximum efficiency.  Linear Technology argued for most uniform color across brightness.





Title: Re: High Efficiency LED for Joule Thief, etc.
Post by: gotoluc on August 20, 2015, 04:11:00 PM

Hi GotoLuc,

Those box LED grow light usally use when measured out of the box around 180 Watts  , a frend of mine uses them.

I myself have ordered some 80W grow lights ( from China ) and they use around 43W out of the box.
http://www.aliexpress.com/store/product/2pcs-lot-E27-E40-80W-640Red-160Blue-Hydroponics-Plant-Lighting-85-265V-LED-Grow-Light-free/835980_1699470283.html (http://www.aliexpress.com/store/product/2pcs-lot-E27-E40-80W-640Red-160Blue-Hydroponics-Plant-Lighting-85-265V-LED-Grow-Light-free/835980_1699470283.html)

Just wanted to share the info.  Because i too want my indoor aquaponics be capable of running solar.

Thanks for sharing Cherryman,

those look to be a great deal. So if anyone can buy 2 of these for the price of one I was suggesting I'm sure it would be good enough for TK to make some tests.

No offers yet and hopefully the drop in price will help get a sponsor.

Luc
Title: Re: High Efficiency LED for Joule Thief, etc.
Post by: tinman on August 20, 2015, 05:04:24 PM
Yes, the issue of interest here is the practical application of the light from these LEDs. Simple illumination is one thing, but there is presently considerable interest in indoor hydroponic farming, using LEDs for plant growth when sunlight isn't available. So here's where what we've learned about LEDs and Joule Thieves starts coming into play.
MarkE is of course right that the standard JT is mostly for allowing use of the residual energy in depleted batteries, or running LEDs from other low-voltage sources. But we've learned from JTs that LEDs can be "overdriven", that is, driven in pulse mode at higher than the nominal continuous DC drive, and can produce even brighter momentary light pulses, so that the LED seems exceptionally bright to the human eye.
So, instead of JTs running at low input voltages, let us consider whether ordinary pulse-width modulation, overdriving the LED for small duty cycles, can produce any effects, like maybe improved yield/power ratios, when used for plant growth. Would there be any efficiency gain, for example, by driving a bank of LEDs at a high frequency 50 percent duty cycle, at higher than normal drive currents (with another bank phased 180 degrees perhaps, so that the plants would see "continuous" light)?

Remember this one TK ?

https://www.youtube.com/watch?v=hvf9Uo7UVx0
Title: Re: High Efficiency LED for Joule Thief, etc.
Post by: MarkE on August 20, 2015, 05:24:59 PM
Remember this one TK ?

https://www.youtube.com/watch?v=hvf9Uo7UVx0
It is a mnice demonstration of why AC power must be calculated by mutliplying instantaneous voltage and current.
Title: Re: High Efficiency LED for Joule Thief, etc.
Post by: Magluvin on August 21, 2015, 04:40:40 AM
Tinsel
A sizzling Topic ATM ...
Think PINK
I am very Happy to see "you" working on this .

https://www.youtube.com/watch?v=ILzWmw53Wwo (https://www.youtube.com/watch?v=ILzWmw53Wwo)

http://www.terraspheresystems.com/index.php/news-media/19-news/41-urban-farming-20-no-soil-no-sun (http://www.terraspheresystems.com/index.php/news-media/19-news/41-urban-farming-20-no-soil-no-sun)
From Above link  I square ft of Vertical farming WILL YIELD 64 head of lettuce per arum, where as 1 square foot of Land farming
?? MAY ??   yield 3 heads per anum.[Ideal conditions]

Establishing Crop yields per square foot against energy required to run the LED's would be wonderful to know ,do they have to run at full power ?
I do understand that PWM would NOT be acceptable for growing crops ,you can trick the eye But not mother nature [thx Brad].
Or would PWM be appropriate for part of the plants 24/7 365 artificial day ??

This is the future.....

Chet K

"I do understand that PWM would NOT be acceptable for growing crops ,you can trick the eye But not mother nature [thx Brad]."

Well that would need to be tested. Remember sliders little circuit that emitted high freq and plants near by grew better. What was it, 27mhz?  Leds should be able to produce that, as I think optical fiber data transmission I believe is much higher than that.

There may be a freq of pulsing the led that the plants like and possibly a freq that they dont like.

Most plants, especially when young, their leaves and branches very noticeably reach for the sun and settle down at night.  If they lean away from a freq they dont like, then maybe dont use that freq. The leaning toward or even leaning away from a freq of light would be cool to see if it happens, and would be a quicker indicator of proper, or not, freq rather than waiting for just growth health and speed.

It would have to be tested. But I wouldnt negate the possibility that pulsing them may be beneficial or even no problem at some freq.



Mags





Title: Re: High Efficiency LED for Joule Thief, etc.
Post by: MarkE on August 21, 2015, 05:42:46 AM
"I do understand that PWM would NOT be acceptable for growing crops ,you can trick the eye But not mother nature [thx Brad]."

Well that would need to be tested. Remember sliders little circuit that emitted high freq and plants near by grew better. What was it, 27mhz?  Leds should be able to produce that, as I think optical fiber data transmission I believe is much higher than that.

There may be a freq of pulsing the led that the plants like and possibly a freq that they dont like.

Most plants, especially when young, their leaves and branches very noticeably reach for the sun and settle down at night.  If they lean away from a freq they dont like, then maybe dont use that freq. The leaning toward or even leaning away from a freq of light would be cool to see if it happens, and would be a quicker indicator of proper, or not, freq rather than waiting for just growth health and speed.

It would have to be tested. But I wouldnt negate the possibility that pulsing them may be beneficial or even no problem at some freq.



Mags
Raw PWM is primarily a way to save money on parts.  If pulsing were a problem, the same average light output can be had by PWM'ing into an LC low pass filter so that the current ripple, and therefore light variation is very small.  PWM rates above around 100kHz will start to distort due to the turn-off time of the LEDs.  If RF does something good for the plants, it is probably more practical to just set up a separate transmitter.
Title: Re: High Efficiency LED for Joule Thief, etc.
Post by: ramset on August 21, 2015, 06:50:29 AM
Mags
Yes the 27 MHz would of course be tested here too(the company from Ireland's tech)
Your idea to watch the little fellows and their reaction is very cool and makes me want to do the best possible job !!
Tinsel
What is an appropriate amount of lights for you to test (watt load) ?

Mark E
Your input is greatly appreciated !

Respectfully
Chet
Title: Re: High Efficiency LED for Joule Thief, etc.
Post by: Magluvin on August 21, 2015, 07:14:27 AM
Raw PWM is primarily a way to save money on parts.  If pulsing were a problem, the same average light output can be had by PWM'ing into an LC low pass filter so that the current ripple, and therefore light variation is very small.  PWM rates above around 100kHz will start to distort due to the turn-off time of the LEDs.  If RF does something good for the plants, it is probably more practical to just set up a separate transmitter.

Back in 8th grade, I bought al laser diode and I think it was 7 9v batteries and built a circuit from a book at the library.  I think it was only 10khz operation. But the book explained that the pulsing circuit enabled the lasing function. Dont remember the wording on that for sure.  was back in 78.  But later I played with the idea of getting an led, 10m red radioshack, to produce the lasing function.  It was like a region of pulsed current operation that gave some turbo to the output.

Those 10mm reds produced a half decent image of the square chip on a wall.  Use a magnifying glass and it becomes so visible in detail, you can see on the wall/white paper the anode wire and a darker spot where it connects to the chip.

When I pulsed it trying diff freq and input levels, when you get close, you will see just one side of the chip emit a much brighter light. Increase input very gradually and another side brightens, and so on till all sides are kickin. 

Dont remember if it was necessary back then to get the lasers to work properly, and now they can just be dc in, but the effect on the led can be had regardless. The JTs are possibly pushing the leds in this lasing region.   The laser diode I used was IR and I used a dental exray test card from my uncle to see the beam. But when the batteries got low, the beam would sorta fall out and perform more like an IR led and no coherent beam.  Lol. Actually tried to file the side of an led, cutting away some of the alum bowl that holds the chip, to hopefully get a beam out the side. Very wishful and ambitious thinking. Was very careful with what tools I had. But always seemed to kill or short/damage the chip before I could end up seeing light from the chips edge.

IR lasers were $27 back then. Red were out of my price range. Way out if I remember correctly.

Mags

Title: Re: High Efficiency LED for Joule Thief, etc.
Post by: MarkE on August 21, 2015, 12:38:30 PM
Back in 8th grade, I bought al laser diode and I think it was 7 9v batteries and built a circuit from a book at the library.  I think it was only 10khz operation. But the book explained that the pulsing circuit enabled the lasing function. Dont remember the wording on that for sure.  was back in 78.  But later I played with the idea of getting an led, 10m red radioshack, to produce the lasing function.  It was like a region of pulsed current operation that gave some turbo to the output.

Those 10mm reds produced a half decent image of the square chip on a wall.  Use a magnifying glass and it becomes so visible in detail, you can see on the wall/white paper the anode wire and a darker spot where it connects to the chip.

When I pulsed it trying diff freq and input levels, when you get close, you will see just one side of the chip emit a much brighter light. Increase input very gradually and another side brightens, and so on till all sides are kickin. 

Dont remember if it was necessary back then to get the lasers to work properly, and now they can just be dc in, but the effect on the led can be had regardless. The JTs are possibly pushing the leds in this lasing region.   The laser diode I used was IR and I used a dental exray test card from my uncle to see the beam. But when the batteries got low, the beam would sorta fall out and perform more like an IR led and no coherent beam.  Lol. Actually tried to file the side of an led, cutting away some of the alum bowl that holds the chip, to hopefully get a beam out the side. Very wishful and ambitious thinking. Was very careful with what tools I had. But always seemed to kill or short/damage the chip before I could end up seeing light from the chips edge.

IR lasers were $27 back then. Red were out of my price range. Way out if I remember correctly.

Mags
Ordinary LEDs do not operate as LASERs.  JTs are essentially boost mode DC-DC converters.  When the voltage is greater than LED Vfw the LEDs light.  Current to an ordinary LED can be managed with a simple current limiting resistor.  That is entirely impractical with a LASER diode.
Title: Re: High Efficiency LED for Joule Thief, etc.
Post by: Cherryman on August 22, 2015, 09:13:20 AM
"I do understand that PWM would NOT be acceptable for growing crops ,you can trick the eye But not mother nature [thx Brad]."

Well that would need to be tested. Remember sliders little circuit that emitted high freq and plants near by grew better. What was it, 27mhz?  Leds should be able to produce that, as I think optical fiber data transmission I believe is much higher than that.

There may be a freq of pulsing the led that the plants like and possibly a freq that they dont like.

Most plants, especially when young, their leaves and branches very noticeably reach for the sun and settle down at night.  If they lean away from a freq they dont like, then maybe dont use that freq. The leaning toward or even leaning away from a freq of light would be cool to see if it happens, and would be a quicker indicator of proper, or not, freq rather than waiting for just growth health and speed.

It would have to be tested. But I wouldnt negate the possibility that pulsing them may be beneficial or even no problem at some freq.



Mags


Some people use moving lights or plants to cover more m2 with less light.


So..   a moving light could also be seen as a frequency.
Wind moving leafs in and out of shadow.. is also a frequency.


Although the more light the better i presume..  one might be able to get a descent result with way less energy use by pulsing.


 
Title: Re: High Efficiency LED for Joule Thief, etc.
Post by: MarkE on August 22, 2015, 01:11:46 PM

Some people use moving lights or plants to cover more m2 with less light.


So..   a moving light could also be seen as a frequency.
Wind moving leafs in and out of shadow.. is also a frequency.


Although the more light the better i presume..  one might be able to get a descent result with way less energy use by pulsing.
There should be some maximum intensity of light beyond which there is no benefit and potentially even harm.  As to pulsing I doubt tha it does any good on its own.  We know from experience in northern latitudes that huge plants can be grown when exposed to light nearly 24/7.  So 24/7 continuous light is probably your baseline, and the object would be to find optimum intensity.  Once one has such a baseline, then one can do things like pulse width modulate to try and see if higher yields per average lighting Watt can be had.
Title: Re: High Efficiency LED for Joule Thief, etc.
Post by: SoManyWires on August 22, 2015, 04:41:20 PM
There should be some maximum intensity of light beyond which there is no benefit and potentially even harm.  As to pulsing I doubt tha it does any good on its own.  We know from experience in northern latitudes that huge plants can be grown when exposed to light nearly 24/7.  So 24/7 continuous light is probably your baseline, and the object would be to find optimum intensity.  Once one has such a baseline, then one can do things like pulse width modulate to try and see if higher yields per average lighting Watt can be had.

yes the lights would need to be brighter to be able get more in harvest yield when using the same area of space, not accounting for other variables, such as temperature, humidity, c02 levels (though plants can more effectively digest c02 in slightly warmer temperatures), the plants ability to use whatever its given for plant food, and placement in respect to the light source.

there is ways to place the plants to be able to take greater advantage of the light source(s).
one example is the Omega garden system that uses no light reflectors, as it can rotate the plants themselves around the light, rather than using a linear light moving rail system. though cleaning the omega system might be an issue.
this makes good use of light when not wanting to pay as much on the power bill.
the light in that system is sealed to protect from water damage, and is placed in the centre of a vertically rotating structure that holds the plants in place, allowing the plants to move around the light.

there are lots of other different garden designs than that one too that make good effective use of a individual light source.

the concern with a individual light source being expected to become usable light is plants can get burnt from heat radiation
if kept too close to the light, airflow has been used to redirect the heat away from the source by using exhaust venting,
and even venting sometimes is not enough as the plants continue to grow towards light, leading to a schedule for adjusting light distance that becomes more important according to the heat.



am thinking that to get higher yields using PWM more effectively with the same input power, a crop would need to be using twice the square footage in garden space (ground coverage) than to try to expect any kind of greater yield from half the space if using the same input wattage, and would need more sources of light to match the area.







Title: Re: High Efficiency LED for Joule Thief, etc.
Post by: Magluvin on September 08, 2015, 03:20:04 AM
I had talked to Chet a while back about indoor gardening, of food, of course. ;D

Here much later on I am going to try a few things.

What I have envisioned is grow modules. Modules that can stack against a wall in an apartment say where you dont have much option for growing food..

The construction material of choice for me is 1/4in pvc board. Light weight, water proof and easy to work with.

Below I have some pics of leds Im going to try.  A 5m real of blue and 5m roll of red.  Also have a role of UV to try with the blue n red. Led spacing is about 5/8in.  Average of about $12 a roll on amazon. Banggood.com even less.

Running the blue and red rolls together use 5.9A at 13.1v. 77w

The strips can be cut at intersections and solder wire to make new connections to consecutive strips. Not sure what size cabinet to make yet, or if it will need all 10 yards of blue n red, along with uv strips.

Its not always that the light has to come from only above the plants. Side lighting helps keep plants short, not having to reach for the light and keeping stem lengths short. More bushy and more nodes for fruit like strawberries, and denser thicker greens.

And if all works out well, the cabinets can be small, stackable, where one could have a full garden on one wall of an apt or room in a house, without taking up much living space.

Will make a new thread if there is some interest shown to do so.


I have some hope for these led strips. It allows easy mounting, self stick, and the ability to easily line the ceiling and walls of the cabinet. And I think its cheaper than what they have out there for the purpose.

Also looking into mylar for added reflection of light. Any light that does not 'end' up on the plant is wasted. Mylar is over 99% reflective. Shiny side of al foil is about 77%. Actually a titanium white paint is better than foil.

Mags
Title: Re: High Efficiency LED for Joule Thief, etc.
Post by: SoManyWires on September 08, 2015, 07:26:02 AM
I had talked to Chet a while back about indoor gardening, of food, of course. ;D

Here much later on I am going to try a few things.

What I have envisioned is grow modules. Modules that can stack against a wall in an apartment say where you dont have much option for growing food..

The construction material of choice for me is 1/4in pvc board. Light weight, water proof and easy to work with.

Below I have some pics of leds Im going to try.  A 5m real of blue and 5m roll of red.  Also have a role of UV to try with the blue n red. Led spacing is about 5/8in.  Average of about $12 a roll on amazon. Banggood.com even less.

Running the blue and red rolls together use 5.9A at 13.1v. 77w

The strips can be cut at intersections and solder wire to make new connections to consecutive strips. Not sure what size cabinet to make yet, or if it will need all 10 yards of blue n red, along with uv strips.

Its not always that the light has to come from only above the plants. Side lighting helps keep plants short, not having to reach for the light and keeping stem lengths short. More bushy and more nodes for fruit like strawberries, and denser thicker greens.

And if all works out well, the cabinets can be small, stackable, where one could have a full garden on one wall of an apt or room in a house, without taking up much living space.

Will make a new thread if there is some interest shown to do so.


I have some hope for these led strips. It allows easy mounting, self stick, and the ability to easily line the ceiling and walls of the cabinet. And I think its cheaper than what they have out there for the purpose.

Also looking into mylar for added reflection of light. Any light that does not 'end' up on the plant is wasted. Mylar is over 99% reflective. Shiny side of al foil is about 77%. Actually a titanium white paint is better than foil.

Mags

good idea you have there!
and yes it does make sense trying to utilize more than only one light source, and can help create a more stable even temperature.
(less node stretching your right)

is there enough usable light the plants will respond to with just the LED strip rolls that are being used?
plants do enjoy their radiation.
the more radiation they have without going overboard, the better. similar to a engine fuel for performance.
in eco mode, less fuel.

the result of not enough 'useable light' is smaller tomatoes, and more green leafy produced plant matter,
though you are probably wanting less leafy matter, and instead more tomatoes.

most plants would prefer to be under conditions that would cause people to get sunburns, and mutations.

airflow should be allowed. this can also help control the heat that results from applying enough radiation,
and also convert the plants starch towards creating strength to withstand the weight of tomatoes.

also be aware of Ph levels being not low enough such as tap water.
too low though, can make for shock, ideally somewhere around 6.0 - 6.3.
and for plants just germinating, the ph can be allowed to be a little lower to about 5.5 - 5.8.

more importantly than adjusting ph levels for already developed plants (with roots, ones without roots have very little plant food requirement and will do just fine getting by on what clorophyl they already have until later) is not expecting the plant
to live on a water diet, it also wants some kind of a plant food.

imagine you already are aware of much of that, though its helpful to knowledge that should others consider such an idea that could save time and R&D expense.

also, if saving power is important, then only 18 hours of artificial light (or any light) is all thats needed until at which point the plant is allowed to experience shorter photovoltaic periods at about 12 hour cycles instead until harvest with the help of a timer.

so, more tomatoes, or more lettuce, that is choice.

another thing to be concerned about, is how effective is the adhesive mentioned thats being relied on to withstand the climate they are being used in.

mylar is best, though ya just using white paint can be effective if not easier to clean (if semigloss or higher).

growing in a small containment will mean the temps will rise, this is when a small amount of c02 introduced into the system can be most effective if careful enough to not just exhaust the c02 away from the small containment zone before it can be of use. just try not to place the exhausted c02 into another contained environment that people could be affected by.

all the best