The 22R resistor was calculated so that with 1.3v per cell (nimh), the current in each led is ~30mA (nichia gs max continuous value)
Original leds are very overdriven... with 1.5v (fresh alkaline) ~100mA per led!!!
My nichia gs have lower Vf than the original leds, so if i didn't change the resistor they would be even more overdriven than the original leds... don't know how much the nichia can take ...
First I should say that I am a total newb with electronics, I have read extensively in the forum and am getting a grasp of the concepts, but with my dim original Tikka Plus, am somewhat still in the dark :laughing:.
Reading about some of the massive improvements in brightness, I also want to mod my Tikka Plus (the one with 3 levels plus strobe).
But what concerns me is the above mentioning of overdriven Nichia LED's, both the ?original? and the Nichia mod ones, which are rated at 30mA.
Is this correct? "the orginal LED's are overdriven"? Does every one agree with this?
Petzyl surely wouldn't design this way else there would be
too many warranty returns. ?
If I wanted to confirm the mA draw of my own original Tikka Plus, I should switch to high mode then measure with a multimeter (set to Amps) in series between the battery negative and the circuit. Then take this number and divide by the 4 LED's - right?
THE NEED TO CHANGE THE RESISTOR AS WELL:
For those who have done the mod - Can you provide feedback on the long term use of the modded Tikka Plus after just changing to Nichia LEDs, not the resistor.
Given that the Tikka Plus is a direct drive, and that different batteries could be used (Alkaline 1.5v, NiMH 1.2V), the voltage and so the mA to the LED will vary greatly. From prior posts to this thread "the total current from the [fresh] batteries reaches 170mA" - well above the 30mA spec.
Does this mean that over driving the LED in a Tikka Plus is unavoidable?
Or that the Vf of the new Nichia LED's did not correctly match to the original ones? If so, how should I properly match new LED's to ensure no over driving?
Some mentioned replacing a resistor. Maybe rather than replacing it, which could be difficult being surface mounted, another could be added in series - Is this plausible? If so, what and where?
With so many questions, I am overwhelming myself!!
With the above in mind....maybe it is better to look at the final goal and work backwards...
BEST SOLUTION?
I wanted to use these
Nichia NSPW500GS-K1 LED's, which are If 30mA, Vf 3.2 typical - 3.5 max, rank W: min 31000 mcd - max 44000 mcd
Ideally I would be happy with 50-75% brighter light and some increase in runtime.
If the Nichia NSPW500GS-K1 are not ideal for the Tikka Plus, what are the best LED's to use? Maybe just a different Vf rated one to solve the over driven issue?