Cree XR-E in Fenix L1/2T (vs. UWAJ, stock)

[UnknownVT]

EngrPaul wrote: "Are the POST #15 beamshots accurate for the L1P-XRE mod that became available at Fenix-Store today?"

Sorry - don't know.
I don't have a Cree mod'd L1P to compare.

By speculation/guessing - they may be similar - but this is a GUESS only.

The L1P circuit for a R-bin 1watt Lux1 may actually be closer for a Cree XR-E -since both LEDs are rated for 350mA current.

However beware the L1P was only spec'd for voltage range of 0.9~1.7V - so a 3.7V Li-Ion rechargeable is way too high......

Note: I have editted to add the current draw readings for the respective battery types in the opening Post #1, and Post #15

 

[AlexGT]

Do you think the CREE led might work with a L2P? I am so tempted to try to do the mod.

AlexGT

 

[UnknownVT]

Part 3 -

Using the most "obvious" battery - the common 1x Alkaline AA -

vs. Stock Fenix L1T both using 1x Alkaline AA both on High -

not surprisingly (like the NiMH results in Post #15) - the Cree is noticably brighter than the stock L1T with both on High.

vs. Stock Fenix L1T both using 1x Alkaline AA both on Low -

even when both are on Low the Cree is still noticably brighter -
this may not be such a good thing - as most people would like a dimmer low.
However, bear in mind this L1/2T circuit was not designed for a Cree XR-E -
and there are two ways of looking at this -
either we get pretty good brightness for about 10 hours of runtime (like the stock version) on low -
or a properly designed circuit would give us a lower output at even longer runtime -
think about the region of ~20 hours for a reasonable low output level like 1/2 this brightness?......

vs. UWAJ mod L1T both on 1x Alkaline AA both on High -

Remember a U-bin is about as good as a LuxIII can get currently - and the Cree is definitely brighter.

vs. UWAJ mod L1T both on 1x Alkaline AA both on Low -

Again the Cree even on low is noticably brighter - see comments above for the comparison with the stock on Low.

Control Reference Comparison -
Cree XR-E L1T with 1x Alkaline AA on High vs. Fenix P1 on primary CR123A

the Cree XR-E even on a humble common 1x AA alkaline is actually about the same - or just brighter than a Fenix P1 on a primary lithium CR123A - I think this is pretty amazing......

Cree XR-E L1T with 1x Alkaline AA on Low vs. Fenix P1 on primary CR123A

not surprisingly the Low is not as bright - but even the low seems not that distant from the Fenix P1 on a primary lithium CR123A -
since this is the standard L1T circuit - that's about ~10 hours regulated runtime at this level....... so a properly designed circuit could give us hopefully over ~20 hours runtime at a reasonable low level no problems......

Thinking of it with a Cree XR-E to be truly useful one should think in terms of 3 stages - High like as tested, Medium like the current "Low" with about ~10 hours regulated runtime, and a real Low regulated at about 1/2 the brightness with runtime in excess of ~20 hours......

Current Draw readings on 1x Alkaline AA -

Cree XT-E in L1/2T head -
High = 0.80A
Low = 0.22A

stock L1T
High = 0.80A
Low = 0.25A

close enough to be "identical" - so runtimes are probably going to be similar to the stock L1T.

 

[UnknownVT]

AlexGT wrote: "Do you think the CREE led might work with a L2P? I am so tempted to try to do the mod."

I would think yes.

Since 4sevens is selling a L1P mod'd with Cree XR-E - I would think/guess the L2P would even be better -
with maybe the possibility of being able to handle 3.7V Li-Ion rechargeable battery (but please double check before doing so) -
and definitely can use the CR123 body with Primary CR123 lithium.

Please do let us know how you get on and what you have to do.....

BTW - 2x AA is the next on the agenda in this continuing comparison review -
I'll probably eventually do both -
but should I use 2x AA NiMH, or alkalines first?

 

[BentHeadTX]

I wonder if the 5 ohm resistor in the tailcap switch trick works with the L1T? Click in the resistor for a much lower low, click it back out for "medium" (low) and high is high. Doing the tailcap mod would make it a twistie but it might work for the lowest of the low fans out there.

 

[Calina]

As the brigtness of LEDs keeps increasing we will need more and more levels on our lights to play with. The problem is that once you go over 3 or 4 levels the twisting operation to change levels can become cumbersome. A new approach will have to be designed, like selecting the levels with a ring or having 3 levels only but programmable by the user.

 

[magmini from italy]

how long do place to hold turned on the L1T with a 3.7 v before overheat him?

 

[UnknownVT]

magmini from italy wrote: "how long do place to hold turned on the L1T with a 3.7 v before overheat him?"

That's a good question... and the answer is I don't know.

I think on 3.7V Li-Ion rechargeable the Cree XR-E may be over the spec typical ratings - but still well under the maximums.

Looking at the Cree spec sheet they state the max forward current is 700mA and the typical Vf at 700mA is 3.75V (max Vf @ 350mA is 3.9V) -
If the 3.7V Li-Ion rechargeable is direct driving the Cree - then there is 3.7V (nominal) at 580-590mA which is below the Max - but quite a bit above the "typical" 350mA.

The Cree modified head did get warm during my beamshots - but not what I would call noticably hot - it did not feel any hotter than the T- or U-bin heads - but that was just my impression - however I definitely would have noticed if the head got "hot".

So there is a danger of overheating even though the using a 3.7V Li-Ion with the Cree is still well within the maximum specs.

I know that considerable effort (both in reasearch and work) has gone into getting the Cree well heat-sinked for this particular mod, and this may well be an important point for anyone considering a Cree mod and wants to drive it with 3.7V Li-Ion rechargeable.

 

[magmini from italy]

but a 3.7 li ion (14500 in my case) hardly loaded it makes to measure 4.2 v of peak: those are not enough to burn the circuit in few minutes?

 

[UnknownVT]

magmini from italy wrote: "but a 3.7 li ion (14500 in my case) hardly loaded it makes to measure 4.2 v of peak: those are not enough to burn the circuit in few minutes?"

Not sure....

But the L1T/L2T circuit is designed to handle up to +4V.

I know that some Li-Ion cells freshly off the charger can read as high as 4.2V
(this depends on the charger - mine tend to be about 4.09V max) - but this is fairly short -
and once they are under load they do drop to close to their "nominal" voltage of 3.7 or 3.6V.

The 3 different 3.7V Li-Ion rechargeable RCR123 I used did not appear to distress the Cree L1T -
and the protected and Unprotected 14500 Li-Ion rechargeable I used in the stock L1T also did not seem to distress the stock L1T LED - see -

Fenix L1T on 3.7V Li-Ion - Whoa!

However you still do this all at your own risk -
if you want to be on the safe side don't use the Li-Ion fresh off the charger -
just use the Li-Ion battery for a bit before putting it in the flashlight -
afterall they are rated at 3.7 or 3.6V and not 4.2V.....

 

[mkphc]

Sorry for the dumb question-

What's it going to take to have a P1D Cree work w/a protected 123?

i'm new to all these mods so please forgive me being green

but I'm really interested in a single 123 size 100 lumen that'll work w/a rechargeable and this seems to be the ticket!

remember Kermit said "it's not easy being green"
Thanks,
Mike

 

[EngrPaul]

Bring on the L1TD-CE, I'm ready for it!

 

[boonsht]

Bring on the L1TD-CE, I'm ready for it!

I'd be all over that as well

 

[ackbar]

Bring on the L1TD-CE, I'm ready for it!

+1

 

[CodeOfLight]

I HAVE an L1/2 T with a cree in it.

 

[ackbar]

I HAVE an L1/2 T with a cree in it.

Please allow me to be the first to say it....






I HATE YOU

 

[UnknownVT]

mkphc wrote: "What's it going to take to have a P1D Cree work w/a protected 123?"

Hopefully nothing......
Hopefully the P1D circuit will work in a similar way to most step-up and regulating circuits for single CR123 -
that is, when the input voltage (ie: battery) exceeds the intended output voltage (usually set to the Vf of the LED) - the circuit is by-passed - so in effect the light is directly driven by the 3.7V Li-Ion rechargeable RCR123 battery.......

EDIT to ADD - I don't have to be hopeful on this -
according to 4sevens in this thread (Q&A section of the opening post) -

New Fenix Digital Series! P1D and P1D CE with Cree XR-E !!

QUOTE:
Q: Will P1D support RCR123a
A: Yes, it will work however, the three levels will not be regulated. Exact
behavior is yet to be reported.
UNQUOTE

=====================
The hopefully not too distant "L1D-CE" - is what this Cree XR-E mod in the L1/2T head is closest to, and this review is kind of "previewing" what a future L1D-CE is going to be like in performance for the high and medium levels.......

The beauty of the Cree XR-E mod in the L1T/L2T head is that it will accept a 1x AA, 2x AA and the Nekomane CR123 bodies - which makes it a VERY versatile and high performing light - since the L1/2T circuit coupled with the Cree XR-E can be used with 3.7V Li-Ion batteries - both the 14500 (AA size) or the RCR123.......

So hopefully the yet to be announced L1D-CE will follow the same versatility but with better regulation circuitry, therefore good runtimes for the brightness levels.....

I don't think things can get much better than that - for now......

As you see I used "hopefully" a lot in this post -

so it's a hopeful post

 

[LowTEC]

Bring on the L1TD-CE, I'm ready for it!

And they will be charging you 75+ bucks for one since you are so "ready" for it :lolsign:

 

[mkphc]

Thanks! I get it now

 

[yekim]

do you have any luxV lights to compare the cree light to ?