(newbie inside) dirt cheap 1xAA twistie, what is possible?

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AgentSteel
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(newbie inside) dirt cheap 1xAA twistie, what is possible?

Hi,

So I “tore down” this dirt cheap thingy, this is a twistie with a 3-mode driver (mode order is : high, low, strobe Facepalm ) and advertised as XP-G R5 (so I guess a fake of some sort). I intend to use 1xAA NiMH batteries with it.

Is it possible to mod it to only have 1 mode (high) without changing the driver? (ie, shorting or removing a component off it?)

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edit : added some info/corrections

Flashlights, blades & beer
Let’s stay relatively optimist!

Edited by: AgentSteel on 05/21/2017 - 05:26
NeutralFan
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That would be a good mod if you could take out the strobe mode, but unfortunately I’m not sure which chip you would need to disconnect to accomplish that.

I’d rather use my flashlight around the house than turn on the lights.

Pulsar
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You could try removing all components off the driver, and find a positive and negative trace to direct drive the LED. Not sure if it would be able to handle being DD…

What type of cell does it use?

NeutralFan
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The post title states it’s a “1xAA twistie”. So I don’t think direct drive of 1.5 volts would be enough to power the LED. Somehow AgentSteel needs to maintain the boost part of the driver.

I’d rather use my flashlight around the house than turn on the lights.

Pulsar
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Ah, ok… missed a crucial part to the tittle lol…

keltex78
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That’s the old SuperLight that was available a while back. Yes, it’s a LB emitter, but for the price, it was still a surprisingly good little light. I did a XM-L mod on one and it gets hot in a hurry.

Not sure how to disable the modes to make a single-mode operation.

Do you want to keep the AA functionality or are you going to be using a 14500 lithium? These cheap single mode drivers from FT are a good fit for these little lights off you are able to use lithiums…
https://m.fasttech.com/p/1127404


Keepin’ the “B” in BLF

Don wrote:
It sounds like the XM LEDs won’t really be suitable for flashlight use. Pity…

Lightbringer
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keltex78 wrote:
Do you want to keep the AA functionality or are you going to be using a 14500 lithium? These cheap single mode drivers from FT are a good fit for these little lights off you are able to use lithiums… https://m.fasttech.com/p/1127404

Yep, I use those beasties in quite a few lights…

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Jerommel
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I think you can remove one of the capacitors and it will always turn on in the first mode.
But which one? My guess is C2.

AgentSteel
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Thanks for your help guys! (I love this forum Thumbs Up )

Yes, I intend to use 1xAA NiMH with these lights (have 3 of them), just to keep around the house. Not for EDC use, I have better lights of course.

And the thermal path is pretty much inexistant, the emitter pcb is just barely touching the “shelf”.

Jerommel : I will try that (maybe try to short the capacitor with a graphite pen instead of removing it)

Flashlights, blades & beer
Let’s stay relatively optimist!

Jerommel
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I guess you can find out which one it is by trying the pencil trick. Smile

keltex78
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AgentSteel wrote:

And the thermal path is pretty much inexistant, the emitter pcb is just barely touching the “shelf”.

Just barely? On mine, shelf is actually an integral part that the PCB sits flat on. In fact, I actually sanded mine down to remove the dimple in the center, then lapped it to a mirror shine for my XM-L mod and ended up with a great thermal path…


Keepin’ the “B” in BLF

Don wrote:
It sounds like the XM LEDs won’t really be suitable for flashlight use. Pity…

Lightbringer
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keltex78 wrote:
In fact, I actually sanded mine down to remove the dimple in the center, then lapped it to a mirror shine for my XM-L mod and ended up with a great thermal path…

By hand?

Ain’t got a lapping machine, would be great to still be able to do it. Big Smile

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ImA4Wheelr
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Apparently, that boost converter chip (component with 6 legs) also has built in modes.  I tried searched to find its identity, but my Google fu is weak tonight.  If you can find it's data sheet, it will say if the modes can be disabled.  Since there is no apparent zero ohm resistor or solder blob to ground, Jerommel's suggestion about removing a capacitor seems to be the last hope.  The capacitor would be the smallest one on the PCB and only connect to one pin on the boost converter.  I can't clearly see the traces, but neither of the 2 caps appear to be for that purpose.  Hopefully, I'm wrong.  Best wishes.

keltex78
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Lapping machine? That’s sandpaper (fine-grit) on a flat surface. When smooth like you want it, a plain sheet of paper with rubbing compound. That’s how I polished mine out.


Keepin’ the “B” in BLF

Don wrote:
It sounds like the XM LEDs won’t really be suitable for flashlight use. Pity…

Lightbringer
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keltex78 wrote:
Lapping machine? That’s sandpaper (fine-grit) on a flat surface. When smooth like you want it, a plain sheet of paper with rubbing compound. That’s how I polished mine out.

For the flat side of the star, sandpaper on a flat surface is fine, but on the shelf, I’m concerned about taking off more from the middle than around the edges, making it more of a saucer.

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Intracloud
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The modes are in the led driver SOT23-3 (3-legged) marked GY02 . Try bypass pin 1 and 3. This should bypass the “internal” switch and make it 1-mode, assuming I read the schematic correct… Wink

ImA4Wheelr
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^

Nice.  I assumed that was a mosfet for boosting purposes.  That helped me search and find a similar mode mod instructional:

 

http://devjoe.com/2014/09/20/cree-led-flashlight-mod-disabling-different-modes-sipik-sk68-clone/

 

AgentSteel
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Intracloud : Thanks, I will try that as soon as I have proper equipment (I need a magnifier and helping hand)

Flashlights, blades & beer
Let’s stay relatively optimist!