$6.25 Elly 1 Watt has boost/regulated 2h 40m!

In case someone didnt notice this on reviews-thread:

mzzj said:

Turn-on voltage varies from unit to unit because Elly uses mosfet as a switch and mosfet gate treshold voltage is always bit "random". I have one that starts at 0.9v and another starting at 1.1v.

There is a trick to modify Elly driverboard to start reliably every time with less than 0.8v input, all you need is NPN-transistor and one 1k resistor

Connect NPN transistor parallei to Q1. It's very difficult if not impossible to manufacture mosfets with gate treshold voltages below 1v, but ordinary NPN transistor works already with 0.7v!

Emitter goes to Q1 upper pin. (Hold driverboard with inductor upwards.)
Collector goes to Q1 middle pin.
Base connected with 1k resistor in series to Q1 lowest pin

I used BC337-40 transistor but any fairly similar transistor should work. Something "around" 10-100v, 50ma-1A and HFE more than 100.

Click to expand...

Nake said:

So, of the 4 Ellys I have, would the reg board drawing 1300mA deliver more current to the LED than the one drawing 900mA? When testing the lights with batteries, they all appear about the same brightness.

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not sure, could be that or small differences in the batteries or efficiency differences with the reg boards or a combination.

moon lander said:

not sure, could be that or small differences in the batteries or efficiency differences with the reg boards or a combination.

Click to expand...

Or led Vf or converter maximum duty cycle limit.

It appears that my boost circuit is dead after 3 times turning the light on. I took it apart and see that whenever i click the switch on, it is as if it is direct and there is no circuitry in place. Does anyone know a fix for this?

can anyone show me how to remove the boost circuit board out of the metal thing its attached to?

The boost circuit is acting really weird .. it sometimes works and doesn't. Most of the time doesn't. When i power it on and connect the + lead to the LED manually it works but then when I turn it off and turn it back on with the lead still connected it doesn't work unless i disconnect and reconnect the lead. It's like it needs to initially charge up or something and then i connect itll work but not when the led is already connected. Now the circuit doesn't even keep a consistent voltage boost. The voltage it outputs to the LED jumps up and down and the light can be seen getting dimmer and brighter.

nanotech17 said:

joedm,
If run with 14500 thru the board,how long the board can take?
And if direct drive using Alkalines or Nimh any difference compare to direct drive using 14500?

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Don't run a 14500 through the board unless you want it fried! (refer to this post)

Direct drive only with 14500, Alkalines or Nimh cannot start the led requires >3V to turn on.

In terms of the resistor, and direct drive, here is my post about bypassing the circuit for "direct drive"

https://www.candlepowerforums.com/posts/1882764&postcount=411

Basically once you have bypassed the circuit then you can connect your resistor of choice (I use a 1ohm) in series with the led.

Good work mzzj & Bertrik.:goodjob:

I am now going to try to salvage the circuit I fried by replacing Q1 with a BF08 N-channel mosfet or something similar.

I think I'll leave my twist switch in.

Is there a way to modify the circuit (or add to it) to basically sense a voltage > say 2V and divert to direct drive instead of using the circuit?

This would be awesome as I would have a light that could accept any type of cell... hmm..

Man, these Ellies (or is it Elli, lol) are great! I've converted a couple of them to Crees, and have more on order for family. Does anyone know of a source for a glass lens that'll fit these? I know my father and brother will scratch theirs up pretty quickly.

flashlightlens.com has a 24.7mm lens that fits well.

Can anyone show me the way to taking out the circuit board from the metal heatsink?

where do you find glow in the dark o-rings?

Here:

https://www.candlepowerforums.com/threads/138277

I bought several and they work just as advertised. Enjoy.

try painfulpleasures.com

johnny13oi said:

Can anyone show me the way to taking out the circuit board from the metal heatsink?

Click to expand...

I got the circuit board out by using these tools:
http://img80.imageshack.us/my.php?image=toolsqd7.jpg
Doing circular motions with sharp and hard tool around edge of the board and then using a screwdriver inserted in one of the edge vias for prying the board out is what it took for me to get the job done.

Thanks for the help. And I was wondering, would the original LED be direct driven just fine with 3XAAA NiMh without a resistor?

Tried plumbers teflon tape on the threads and now I can adjust the focus like a MiniMag...

today I tried running the elly at 2,4V (2x1,2 NiMH) for 10 min. The current from the batteries was over 3A voltage at bulb 3,4V (It worked and it was very bright!)

johnny13oi said:

Can anyone show me the way to taking out the circuit board from the metal heatsink?

Click to expand...

Just give it a whack. Mount it on vice and place small screwdriver against circuit board edge(not against components or copper traces) and whack it couple of times with hand/screwdriver/sledgehammer.
Some are very loose and others require bit more.

Can anyone show me the way to taking out the circuit board from the metal heatsink?

Just give it a whack. Mount it on vice and place small screwdriver against circuit board edge(not against components or copper traces) and whack it couple of times with hand/screwdriver/sledgehammer.
Some are very loose and others require bit more.

Click to expand...

If it does not go easy enough try taking out the other side first and give it a "blow" from the other side

mzzj said:

Click to expand...

It IS possible to modify stock elly circuit beyond 600mA led current..
Thing is that its way too big then to fit orginal lamp, but could be useful for 1D lantern or something.

Coil is replaced with 10-20uF 4A rated and schottky diode with biggest badass low-Vf schottky you can find. I used giant to-220 47CTQ020.
47uF output tantal cap is replaced with 10-100uF 6v MLCC cap for lower ESR.
10uF MLCC does better job in filtering than stock 47uF tantal.

with these modifications XR-E is running at over 600mA but it wont fit even near elly :laughing: I would need low Vf schottky in small smd package, unfortunately these are made from Unobtanium. Synchronous rectification would be another option, but I dont have any cute&tiny mosfets on stock as my projects usually are in 100's of amps, not milliamps...