McLux PD input voltage

[Nake]

Why do the PDs have an input voltage of only 525mA? I would think with the Crees and Seouls accepting 1A, they could be higher. If I were to acquire one of these lights, could I change the driver board to a higher output one without altering the light (screwing it up)? I don't neccessarily mean myself, but someone more qualified if required. Has anyone done this? I haven't read anything about it.
They are a beautiful light, but I am a performance nut.

 

[Oddjob]

I think Don initially designed his lights as tools and therefore the mA's were thought to be the best compromise for brightness and runtimes. There are probably other reasons but I'm sure he or someone else will chime in.

 

[kenster]

The PD`s with the Cree`s and SSC P4`s perform fantastic with the high drive current set at 525ma IMHO. Of course the drive current could be raised but actually you would not be getting more performance out of the PD Again, this is only my opinion but I believe many would agree with me. The PD is a fairly small light with a fairly small battery. If you raised the drive current to 1 amp, which is almost double, you would be sacrificing your battery to have probably less then half the runtime and I would be willing to bet on it for several reasons. Driving the LED that hard creates a lot of heat for the size of the light and amount of metal it has to dissapate that heat. The hotter the LED becomes the less efficient it becomes as well. With the LED sucking the life out of a small 123 size battery so fast, this creates more heat and more loss in effiency. Don has a fairly good head on his shoulders and the PD`s are an all around top notch light. Again this is just my opinion and I am about two bricks short of a one brick load and I believe many would agree with me on that too. :duh2: Thanks for backing me up guys! :nana:

One thing I would be willing to bet the farm, truck, dog and even a Ti PD on, is that you will get some responses with opinions, both right and wrong so protect your brain and practise safe reading like this..... :tinfoil: :laughing: But don`t worry, the smarter dudes will stop by and explain things better than this dumb dude.

OK, I`m done now! :wave:

Ken

Ken

 

[easilyled]

I think I can answer this ...

ma is a unit of current, not voltage.

For a one-celled light 525ma was found originally by Don to be the
best compromise between brightness and runtime, meaning that you
can have over an hour of runtime on high which still produces an
impressively bright output (just about 100 lumens with Seoul leds).

Driving the led at current higher than 525ma was found to have diminishing
returns because for the sake of not that much more obvious brightness,
the runtime was reduced a lot.

There are 2 main reasons for this:-

1) As leds heat up they become less efficient and they start to heat up
over 525ma. This means that some of the extra current is wasted in
producing heat which in turn hinders the output of the led and shortens its
lifetime.

2) The other reason is that the receptors in our eyes work logarithmically -
so even if a light is producing twice the lumens, it doesn't actually appear
to be nearly twice as bright.

Another reason that could be pertinent to Seoul leds, is that they tend
to shift towards a bluer tint and lose about 12% of their output after a
certain time (maybe 100 hours) and this phenomenon
could be exacerbated by driving them at levels approximating 1000ma

 

[Nake]

Thanks for the replies. I was thinking current but typed voltage. So the best thing to do for more brightness is to replace a P bin Cree with a Q bin one. Now to find an Al PD with a Cree.

 

[Morelite]

Nake, It is possible to change the drive current on the converter boards. It is a PITA to do but someone with good soldering skills can swap the resistor or even double it up with a second one wired in parallel with the existing one. To increase the drive level you need to lower the value of the existing resistor. The SS has a calculator for determining the drive level for different resistor configurations. I'm not sure if it applies to the GD driver (if that is what driver your PD has), but Don or Wayne (at the Shoppe) may be able to help.

 

[mossyoak]

Thanks for the replies. I was thinking current but typed voltage. So the best thing to do for more brightness is to replace a P bin Cree with a Q bin one. Now to find an Al PD with a Cree.

theres one for sale right now i believe in the custom B/S/T.

the reason the drive level is so low is that it give a good runtime /output comprimise. mcG doesnt build stunners he builds rock solid tools.

 

[knifebright]

As an actual real life comparison I would say leave it at 525. your choice though but on one of my PD's i had the same idea.. ya lets crank it up and really get some lumens out!!!! So I bumped the high up to 1000ma give or take a few and the low stayed the same. Sure i gained some light but it did not by any means out weigh or even match what i had lost. I had to use rechargeables if i really wanted 1000ma, had to deal with constant dimming if i used primaries as the little Wiz2 did its best to give its all, I couldn't put the thing down casue my hand had now become an intergral and imeritive part of the heat sinking process.
So after that camping trip i went through the even more PITA of putting it back to its 525 starting point.

525 is there for a reason, I questioned it once and had to find out for myself but 525 it is!

Of course what you do with your light is your business but i hope i maybe can save you a little bit of a headace and burnt finger tips!!

have fun!
Jimmy