XP-G driven at 1A vs 1.4A

[Black Rose]

Trying to figure out which drivers to use for my next builds.

Would there be a big difference in visible output with an XP-G driven at 1A vs being driven at 1.4A?

 

[ShineOnYouCrazyDiamond]

IMHO - big difference no, but completely visible difference - yes.

 

[old4570]

In a word = Yes

I use the SB 1.4A driver with one Xp-G R5 P60 and its almost as good as the ones driven much harder ..

Its a good combo ... and the LED is not driven so hard as to suffer a lot of heat related sag .

 

[Bullzeyebill]

Might make a difference if the host is something like a Surefire C series, or clone. Need really good heat sinking to use the C series head if you are going to 1.4A's compared to 1A to the LED. If not that good heat sinking, your 1.4A will be running at the same output as the 1A'er or lower, very quickly.

Bill

 

[Black Rose]

I'm curently using the SB 1.4A driver in a few builds (P60 drop-ins and some Aurora V6 hosts) and was thinking of trying the L-Mini II driver with XP-Gs due to the amount of heat that is being produced.

A lead wire came off one of my SB 1.4A drivers long after it was installed in a drop-in - not sure if it produced enough heat to unsolder the wire from the board end.

 

[nailbender]

I'm curently using the SB 1.4A driver in a few builds (P60 drop-ins and some Aurora V6 hosts) and was thinking of trying the L-Mini II driver with XP-Gs due to the amount of heat that is being produced.

A lead wire came off one of my SB 1.4A drivers long after it was installed in a drop-in - not sure if it produced enough heat to unsolder the wire from the board end.

HI

I use bryan's 1.4 amp drivers all the time with no problems, you probably had one that already had a loose wire or one not soldered quite tight.
You will get about 320 lumens with the 1.4 amp driver and about 300 lumens with the L mini 1 amp driver so there is not a lot of difference. The l mini runs much cooler and adds about 30 minutes runtime compared to the 1.4 amp driver

Dave

 

[ShineOnYouCrazyDiamond]

I was looking through some XP-G spec PDFs and there is a section on relative luminescence. The basis for the rating is the standard 350mA flux rating is the 100% brightness point.

For 1.0 A the relative rating is 250% and for 1.4A it is approx 320%.

So for a Q5 rated @ 107lm @ 350mA.
1A = 107 x 250% = 107 x 2.5 = 267.5lm
1.4A = 107 x 320% = 107 x 3.2 = 342.4lm

Keep in mind this is all relative to other ratings. Can the driver maintain 1.4A? Relative brightness drops with junction temperature. More drive = more heat. OTF losses, etc.

YMMV

 

[vaska]

I was looking through some XP-G spec PDFs and there is a section on relative luminescence.

Why not to have a look at this instead of speculating?

 

[ShineOnYouCrazyDiamond]

Why not to have a look at this instead of speculating?

Excuse me - I never said I was speculating.

I took exact figures straight out of the PDF document.

The information you have linked to is ONLY good for R5 flux bin XP-G LEDs. The information on "Relative Luminescence" is valid for any flux bin XP-G LED as long as you know the lm/w information for that bin.

 

[vaska]

I took exact figures straight out of the PDF document.

According to my experience datasheet diagrams are rather rough. You can chech their accuracy by the data from the linked table. For example, according to it 1A/350mA factor is not 2,5 but 2,42. And 1,4A/350mA factor is 3,04 - not 3,2.

 

[ShineOnYouCrazyDiamond]

According to my experience datasheet diagrams are rather rough. You can chech their accuracy by the data from the linked table. For example, according to it 1A/350mA factor is not 2,5 but 2,42. And 1,4A/350mA factor is 3,04 - not 3,2.

Like I had mentioned above - Keep in mind this is all relative to other ratings. Can the driver maintain 1.4A? Relative brightness drops with junction temperature. More drive = more heat. OTF losses, etc.

So if you factor these things in you will get the drop to the numbers you are describing.

Since OTF losses can not be mitigated that much, the other factors which can be controlled are heat dissipation and current supply. Larger batteries or better drivers (ie: buck/boost to maintain a constant forward current) will help as will good flashlight design with proper heat sinking.

 

[ti-force]

I have a Quark 123-2 XP-G R5 that I modded with a Shiningbeam 1.4A driver, but I added an additional 7135 chip to bump the current up to roughly 1.7A. Here are my OTF results for this light, and for an un-modded Quark 123-2 XP-G R5:


_____Quark 123-2 XP-G R5 SB 1.7A mod____
___1 sec______357.6___________
__30 sec______305.5_________
___1 min______297___________
___2 min______292.1_________
___3 min______289.7_________


_____Quark 123-2 XP-G R5______
___1 sec______257___________
__30 sec______241.2_________
___1 min______238.8_________
___2 min______236.4_________
___3 min______235.2_________


As you can see, the 1.7A mod loses 67.9 OTF lumens from 1 sec to 3 min, while the non-modded 123-2 Quark only loses 21.8 OTF lumens.

At 1 sec the 1.7A mod is 100.6 OTF lumens higher than the non-modded Quark 123-2 at 1 sec. At 3 minutes the 1.7A mod is 54.5 OTF higher than the non-modded Quark 123-2, while it's 64.3 OTF higher at 30 sec, so most of the losses are within 30 sec, and it seems to fall fairly steady from there. I would expect the losses to be less with a drive current of 1.4A, but I couldn't say how much unless I tested one. I would also expect the losses to be less with an XP-G R5 with 1.7A drive current in a light that has more mass for heatsinking than the Quark has.

I wish I had one modded with the 1.4A driver without the additional 7135 so we could see how much of an increase there is from the factory Quark driver (roughly 900mA) to the 1.4A SB driver, but I don't.

 

[MikeAusC]

You'll have no trouble measuring the difference in Light level from 1 to 1.4 amp, but the eyes response is not linear.

The brightness steps in multi-level drivers are usually between two and three times because just perceives a 2 times change as a small change.

 

[wachtel]

Hi ti-force

I modded an Aurora V6 with Cree XP-G and SB 1.4A driver.

The LED is fixed with Arctic Silver 2-comp. at the pill and the pill is
screwed into the battery body with
Arctic Silver 5 thermal paste to realize
the best thermal transfer which is possible with that small sized lamp.

Here is the temperature curve I measured in High mode

(German flashlight forum)

http://www.taschenlampen-forum.de/modding/642-bau-fahrrad-alltagslampe.html


Wachtel

 

[ShineOnYouCrazyDiamond]

I just received my 1A NB drop-in yesterday and have been doing some comparisons.
- NB XP-G Q5 3000K 3-level 1Amp regulated
- NB XP-G Q5 3000K 3-level 1.4Amp regulated

Completely non-scientific white wall hunting and tree illumination tells my eyes and brain that for all practical purposed these two lights are pretty much equal in brightness.

 

[ti-force]

Hi ti-force

I modded an Aurora V6 with Cree XP-G and SB 1.4A driver.

The LED is fixed with Arctic Silver 2-comp. at the pill and the pill is
screwed into the battery body with
Arctic Silver 5 thermal paste to realize
the best thermal transfer which is possible with that small sized lamp.

Here is the temperature curve I measured in High mode

(German flashlight forum)

http://www.taschenlampen-forum.de/modding/642-bau-fahrrad-alltagslampe.html


Wachtel

Thanks for posting, but I'll have to wait until I'm on my home computer before I can view the thread you linked to; my German isn't that great

I just received my 1A NB drop-in yesterday and have been doing some comparisons.
- NB XP-G Q5 3000K 3-level 1Amp regulated
- NB XP-G Q5 3000K 3-level 1.4Amp regulated

Completely non-scientific white wall hunting and tree illumination tells my eyes and brain that for all practical purposed these two lights are pretty much equal in brightness.

Yes, I agree that for up close use you probably won't notice much difference. At a longer distance the output may be more noticeable. I usually can't see differences in brightness against a wall because the human eye adjusts to the brightness, so I usually compare at a distance to see small differences in brightness. Of course everyone's eyes are different, and age plays a role too (like everything else ).

 

[ShineOnYouCrazyDiamond]

Yes, I agree that for up close use you probably won't notice much difference. At a longer distance the output may be more noticeable. I usually can't see differences in brightness against a wall because the human eye adjusts to the brightness, so I usually compare at a distance to see small differences in brightness. Of course everyone's eyes are different, and age plays a role too (like everything else ).

The trees I was illuminating were not "up close" but also not more that 50-75 feet out. I'll be doing some walking in the woods over the next day or two and will bring both of these lights with me. I'll report back as I do agree with the statement that distance can bring out the subtle, yet still present, difference in the brightness.

and age plays a role too (like everything else ).

......So...... what're you trying to say? LOL :nana:

 

[ti-force]

The trees I was illuminating were not "up close" but also not more that 50-75 feet out. I'll be doing some walking in the woods over the next day or two and will bring both of these lights with me. I'll report back as I do agree with the statement that distance can bring out the subtle, yet still present, difference in the brightness.


......So...... what're you trying to say? LOL :nana:

I usually shine out 50+ yards; I find that distance makes it easier for myself. See if you notice the difference better at that distance. The age comment was aimed towards the pupil not able to dilate as much as we age. It seems like we hit a certain age and everything starts to fall apart

 

[luxrc]

good result (+28% @1.55A) achieved when a thermally enhanced copper core board is used:

I update my experiments with XP-G running at high currents in this thread:
http://www.candlepowerforums.com/vb/showpost.php?p=3495590&postcount=45

 

[ShineOnYouCrazyDiamond]

I usually shine out 50+ yards; I find that distance makes it easier for myself. See if you notice the difference better at that distance. The age comment was aimed towards the pupil not able to dilate as much as we age. It seems like we hit a certain age and everything starts to fall apart

ti - I went out tonight for a nice long walk. To be honest after 30 minutes in the dark woods with some real long distance throw sections I really couldn't tell any discernable difference between the 1A and 1.4A XPG lights.

For comparison I also had a SST-90 P60 drop-in light with me running at about 3.4A on high. It had about the exact same throw as the XPG but with a much larger spot.