LPC826 and NewWish Diodes - Dual Driver

[Javalin]

DISCLAIMER: I don't own a multimeter or an LPM so this is just proof of concept.

I have an LPC-826 but no driver. Well, not exactly... I bought a bunch of New Wish pens off ebay.

I wanted to use two of the drivers from the New Wish pens to run a single diode.

As I said, I can't take measurements so I relied HEAVILY on measurements taken for me.

Pman measured his pens and I used his numbers on good faith.

First the numbers:
The 650 that is 74mw
2.2V .05A
2.4V .09A
2.6V .13A
2.8V .17A
3.0V .18A and this stays the same all the way to 4.2V

Using the graphs for the LPC-826 they can be safely pushed to 400mW. So if my thinking is correct two of the drivers above connected in parallel will have the same voltage and the amperage will be added yielding 4.2V and 360mA. Well within the safe limit. So what the heck.

I attached the drivers like this -uploaded new more accurate picture-:

In this picture the NewWish Diode is attached because it's what I started with.

I left the buttons operational so I could see the "ramp up" IF there was any and connected a 26650. Then for the moment of truth:

It worked! This is the beam with the NewWish Diode as I desoldered the LPC-826 until I can measure this setup. The dot gets noticeably brighter when the second driver is turned on but I don't have an LPM.

What I thought was interesting is that the New Wish Diode survived at least for the time being. I honestly expected it to LED instantly when it saw what I think should be 360mA.

 

[SKeeZ]

Good job! not sure how practical it is because you could get a single driver set at 360mA but its still cool you didn't fry it.

 

[Javalin]

Thanks Skeez,

This would be much cheaper than buying a 360mA driver, especially for a cheaper build. These drivers came from pens that can be had for less than $5 each. And I'm sure you could pull drivers from some of the fasttech modules that are even cheaper!

I was honestly just looking for a way to run my diodes that didn't invilve buying a $20 driver and was hoping to get a little feed back.

 

[bdgreenb]

ideally the 826 would get more than 360ma, i run mine around 500ma and they have hours and hours of use with no degradation. 360ma is a super safe current, which is smart for early builds. Good thinking Mr.Thrifty Builder

 

[Javalin]

ideally the 826 would get more than 360ma, i run mine around 500ma and they have hours and hours of use with no degradation. 360ma is a super safe current, which is smart for early builds. Good thinking Mr.Thrifty Builder

Thanks for the input! I know 360mA is super conservative but if I add another one of these drivers I would theoretically get 540mA well above what I'd like to push my diode

Although I just had a thought. I could try adding one red driver @ 180mA and a green driver @ 320mA for the 500mA. :thinking: But that's still getting really close to the edge and with no meter I can't verify that my drivers are acting as expected.

 

[bdgreenb]

you dont really want to use two different output drivers in parallel, the weaker one will heat up super fast.

 

[SKeeZ]

how stable is the output?

 

[Javalin]

No clue. DMM and LPM are still on the "To-Buy" list.

 

[SKeeZ]

"Ditto"

 

[Fiddy]

pretty dodgy to only get 360mA out put, you could use a single amc1735 to 350mA.