Joule Lamp

[MileHigh]

Just some "outside of the box" ideas.

Note for any Joule Thief or Super Joule Thief there is an energy overhead to run the oscillator that makes the whole thing work.  Also, there is the argument that for certain applications the sharpest possible on-off transitions for the main power coil are the most desirable.  The JT architecture isn't particularly good at generating sharp transitions.

One possible solution to these two problems is to use a 555 timer.  It's an oscillator that gives you sharp transitions, exactly what you want.  It's also low power.  If you use CMOS 555 timers then it's ultra low power.

So with 555 timers you can emulate exactly what a Joule Thief does and sort of make a clone Joule Thief.

The other thing 555 timers give you is absolute control over the timing.  In a Joule Thief you have a bunch of interacting components that generate the timing so it's much more difficult to control.

With two cascaded 555 timers you can generate a pulse waveform with control over the pulse frequency and also for the length of the "active" pulse.  That corresponds to the flicker rate and the intensity of your CFL or LED light.  So you can really control how much power you send to the light bulb.

MileHigh

[MileHigh]

If I took up the challenge here is how I would do it:

I would take a modular approach.  One module is the solar panel.  Another module is what I will call the "Pulser" that contains the CMOS 555 timers.  The third module is the LED light.  The fourth module is the battery.  Each module would connect to the other module with a nice easy-to-use connector.  I think that I might use a 1/4-inch jack, like a headphone jack.

Daytime:   [Solar Panel] -> [Pulser] -> [Battery]

Nighttime:  [Battery] -> [Pulser] -> [LED Light]

You can see how the battery and the pulser have to move back and forth between outside and indoors each day.  Seeing that it would be tempting to create a single module that combines the two functions.  Then you could have a switch that changes the order that the pulser and the battery are connected together.

The modules:

[Solar Panel] - large enough to do the job

[Battery] - something like a 12-volt motorcycle battery

[LED Light] - a standard 60-watt equivalent LED light but with the electronics stripped off (that just wastes energy)

[Pulser]  - consists of the two 555 timers, a big transistor on a small heatsink, protection neons, a big coil, diode.  This would be like the heart of a classic Bedini motor.  There would be a switch on the module to change the programming of the 555 timers.  One position would select timing suitable for pulse charging the battery from the solar panel.  The other position would select timing suitable for driving the LED bulb to a suitable illumination level.  You could easily add a potentiometer to control the intensity of the LED bulb also.

So the trick here is to use a generic "Back EMF" pulsing coil setup just like in a Bedini motor to do double-duty, charging the battery during the day and powering the light at night.

If you are very careful with the timings that you use to energize the coil, you should be able to maximize your efficiency.  Note the "overhead" for wasted power is very very low in this design.

Finally, here is the Cadillac version of the design:

You combine the pulser module and the battery module into a single module like I stated above.  You know how when you put a cordless phone headset into a cradle it makes contact to recharge?  Same deal here.

Imagine a "basket" with a handle that holds the combined module - the motorcycle battery and the pulser module.  In the daytime you pick up the basket and you bring it outside and drop it into the charging cradle next to the solar panel.   Then at night you move the basket to the power cradle to power the LED light.   That's more expensive of course, but it makes it 100% easier to use.  Note you can go to any garage sale and get some junk cordless phones and then with some determination you could "dissect" the "cradle" parts out and reuse them.

MileHigh

[MileHigh]

Phichaser:

Just wanted to say that I agree that LUX meter is essential to testing bulb brightness. Tune and test, tune and test, tune and test...

How did the Egyptians build the Pyramids and keep them perfectly level?  They simply had a trough around the perimeter and filled it with water.

If you are going to gut a CFL or use it without gutting it in your experiment then you just have to compare the brightness put out by your setup with the same unmodified model of CFL plugged into a 120 VAC socket.  Same thing if you work with an LED light bulb.

Keep it simple and anybody can do it!  Nothing to buy!

MileHigh

[PhiChaser]

Phichaser:

How did the Egyptians build the Pyramids and keep them perfectly level?  They simply had a trough around the perimeter and filled it with water.

If you are going to gut a CFL or use it without gutting it in your experiment then you just have to compare the brightness put out by your setup with the same unmodified model of CFL plugged into a 120 VAC socket.  Same thing if you work with an LED light bulb.

Keep it simple and anybody can do it!  Nothing to buy!

MileHigh

What happens when your DC conversion setup and your 120v house supply start to 'look' the same? I agree with the idea that our eyes are really the 'only' real meter we need for lumens, but how can you 'see' minor changes when you alter minor components (change tunings, whatever...) without some sort of test equipment (not necessarily a meter)?
PC
EDIT: People doing 'research' need some sort of reliable 'platform' to compare results as well...
BTW, I like the 555 timer and phone cradle ideas!

[JouleSeeker]

I totally agree, I have just been lazy to order the light meter.  I will order one and build to your specs so we can compare results.

Hurray!  I think you'll find this is a very useful tool.

...
The question isn't why doesn't the Aircore perform better, the question is why does it perform as well as it does?

Very much agreed.

Busy day (and I'll be out most of this evening) -- but I got several experiments in and made progress, described in this video:


http://youtu.be/Mz2osV3NRDQ

From the text:

More results starting with the circuit designed by Lasersaber (SJR 2.0) and the build by Lynxsteam.  Congratulations, gentlemen, looking good!  I've tried a few variations myself, including addition of a 20-cm-long ferrite core and some cheap 36-LED bulbs I've found.  Finally, I've reached 95 Lumens/Watt running off 17VDC.

Most LED bulbs off-the-shelf in the US give around 50 to 70 Lumens per watt using the grid-mains.  So already, reaching 95 Lumens per Watt is notable (drawing 6 W @ 17VDC) -- and I congratulate Lynxsteam, Lasersaber, Lidmotor, Peanutbutter and all others who have contributed to this progress. 

I am hopeful that friends in Haiti and Mali (who have enjoyed my solar funnel cookers) will appreciate the realization of bright, cheap, off-grid lighting!  We're getting there!