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Author Topic: High Efficiency LED for Joule Thief, etc.  (Read 27662 times)

MarkE

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Re: High Efficiency LED for Joule Thief, etc.
« Reply #15 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.)

TinselKoala

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Re: High Efficiency LED for Joule Thief, etc.
« Reply #16 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.


TinselKoala

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Re: High Efficiency LED for Joule Thief, etc.
« Reply #17 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!

SoManyWires

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Re: High Efficiency LED for Joule Thief, etc.
« Reply #18 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.


gotoluc

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Re: High Efficiency LED for Joule Thief, etc.
« Reply #19 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
 or: 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?

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

SoManyWires

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Re: High Efficiency LED for Joule Thief, etc.
« Reply #20 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
 or: 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?

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.

MarkE

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Re: High Efficiency LED for Joule Thief, etc.
« Reply #21 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.

MarkE

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Re: High Efficiency LED for Joule Thief, etc.
« Reply #22 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
 or: 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?

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.

SoManyWires

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Re: High Efficiency LED for Joule Thief, etc.
« Reply #23 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?


MarkE

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Re: High Efficiency LED for Joule Thief, etc.
« Reply #24 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.

Cherryman

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Re: High Efficiency LED for Joule Thief, etc.
« Reply #25 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
 or: 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?

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

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

TinselKoala

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Re: High Efficiency LED for Joule Thief, etc.
« Reply #26 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)?

MarkE

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Re: High Efficiency LED for Joule Thief, etc.
« Reply #27 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.






gotoluc

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Re: High Efficiency LED for Joule Thief, etc.
« Reply #28 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

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

tinman

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Re: High Efficiency LED for Joule Thief, etc.
« Reply #29 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