UltraFire Cree XR-E dive light

[Packhorse]

I don't like rechargeable Ni-Mg or whatever chemistry accumulators in backup light just because I want to keep it as simple as possible. One can easily forget to charge it before trip or dive...

Just as one can foget to change over non rechargeable cells. I really see no benifit in this regard.

I strongly do not recommend Li-Ion accumulators for backup light. First of all, one must use protected Li-ion cell, although it's quite expencive - could be more expensive then the light itself. But usually people tend to buy cheap cells like TrustFire form DX, which I consider suicide kit for cave of wreck diver. Anyway, if one uses even highly durable and expencive Li-Ion cells, its protection circuit couldn't be more durable then merely contacts of disposable battaries.
The downside of all ather rechargeble accumulators I mentioned earlier also applies here.

I have been using Li Ion cells for DX for a while now. I have not had one fail that wouldnt have failed if it was a better brand.

I found out that this light does not contain LED driver - directly drived LED. I'm staring like it. The simplier backup light, the better. Of course, it will shorten the life of the LED, but who cares?

No driver? Thats interesting. I dont think it makes it better thats for sure. Maybe that is why they dont recommend rechargables due to less voltage sag under load. I'd throw in a 700 or 1050ma 7135 based driver in and use NiMh cells.

 

[Packhorse]

From the pictures it looks identical to the Tilly Tec W30 (300 lumen 3xAAs)...although I assume its not in fact the same given the 162 Euro price tag on the Tilly Tec W30...

upon closer inspection ok maybe not identical but pretty close.

Specs for Tilly Tec

# Diameter: 1.18 in.
# Length: 8.0 in.
# Weight: 3.53 oz.
# Beam divergence: 15 degrees
# Kelvin Color temperture: 5500K
# Lumen output: 300
# Cree 5W with proprietary lens
# Pressure depth: 600 ft.
# Run time: 3-5 hr with fresh batteries (standard AA) @ full power.
# Twist on/off
# Triple seals on light head
# 6061 aircraft grade black anodized billet aluminum

Okay for out of water use.

Not sure if its the same but it probably is.
But lets look at the specs. In particular...

300lumen
Cree 5 watt LED
3-5 hour @ full power

No single emmiter Cree is rated at 300 lumen output.
Cree do not recommend running their LEDs at 5watt.

Now you could run a cree at 5 watt, a R2 cree MAY get 300 lumen but....
There is now way it would run at full 300 lumen output for 3-5 hours.
Infact I doubt it would run at 300 lumen for 3-5 minutes. Not to mention the reduced life span of the LED.

 

[Katolix]

Just as one can forget to change over non rechargeable cells. I really see no benifit in this regard.

I can't say I agree with that. Let me put it in this way: I come to a dive site and I have an armory of batteries and accumulators for many gadgets like camera, another camera, main light, backup light, etc. How could I be sure which accumulators are recharged and I didn't forget anything? So, before series of critical dives I just open new disposable battery package and load the backup light. Even in hurry - which is the main evil impacting safety - I'm quite safe if I did just two things: loaded new batteries, and checked the light switching it on/off. With accumulators the third thing to be added - charging. But this thing couldn't be made quickly and seamlessly with first two..

There is one more argument against particularly Li-Ion - let me mention it a bit further.

Finally, I'm not technical cave diver, but I respect their experience and try to learn from their approaches to safety. Most of those I know through forums use disposable batteries in their backup lights.

I have been using Li Ion cells for DX for a while now. I have not had one fail that wouldnt have failed if it was a better brand.

Glad to know that you had no problems with them. But I know people with the opposite experience. Anyway, neither mine statistics nor yours allows making common conclusions here. My doubts are based on experience with electronic circuits from DX - very often the quality of assembly and/or components is awful and I would never entrust my life to it.

One more argument against Li-Ion per se is the instability of charge depending on ambient temperature. The problems will come if air temperature is below zero (Celsius) - Li-Ion accumulator must not be charged in such conditions and should not be expected for long run time. So, I'll never take a Li-Ion accu based backup light to an ice-dive.

No driver? Thats interesting. I don't think it makes it better thats for sure. Maybe that is why they dont recommend rechargables due to less voltage sag under load. I'd throw in a 700 or 1050ma 7135 based driver in and use NiMh cells.

LED Driver - especially a one from DX - would add one more serious point of failure.
I'd add just a current limiting resistor there to secure from LED burn. I don't care about power effectiveness here - this is backup light. Backup light is not expected to be used during normal dive. And in case of **сkup it's expected to run for an hour or two without significant beam intensity decrease - enough to get out from there. I don't want the cheap LED driver to screw up the rescue plan.

 

[gsk3]

LED Driver - especially a one from DX - would add one more serious point of failure.

I might believe your point about alkaline vs. NiMH or Li (although it seems a bit like substituting inferior equipment to solve a skills issue), but this one is just makes no sense. Bulbs burn out ALL THE TIME. LEDs have shown themselves to be more reliable--even cheap ones--by at least an order of magnitude. And this isn't a cheap LED, it's a Cree.

 

[Katolix]

but this one is just makes no sense. Bulbs burn out ALL THE TIME. LEDs have shown themselves to be more reliable--even cheap ones--by at least an order of magnitude. And this isn't a cheap LED, it's a Cree.

Looks like you missed the point. I was saying that LED Driver - especially a one from DX - would add one more serious point of failure.
A good griver with decent quality (not industrial or military, though) would cost more then $50.
Many of those form DX were thorougly reverse-engineered and it was found out that they were designed by truants and narrow minded engineers.

 

[jtivat]

Looks like you missed the point. I was saying that LED Driver - especially a one from DX - would add one more serious point of failure.
A good griver with decent quality (not industrial or military, though) would cost more then $50.
Many of those form DX were thorougly reverse-engineered and it was found out that they were designed by truants and narrow minded engineers.

Now I am going to disagree these are some of the best drivers made. While some cost $50 many can be had from $13 to $20.

- Sandwich Shoppe

 

[Packhorse]

The type of drive I was thinking of was the 7135 based drivers. Now for a 1050ma driver it takes 3 7135 chips. I will concede one may fail but for all 3 to fail? I doubt it. There is nothing else on the driver board to fail except a diode which I would remove anyway.

Anyway my curiosity has gotten the better of me and I have ordered one of these lights. I will post a review soon. But I doubt it will stay stock for long.

 

[Katolix]

Now I am going to disagree these are some of the best drivers made. While some cost $50 many can be had from $13 to $20.

- Sandwich Shoppe

I can't say anything regarding those drivers, except some of them have specification of which IC they are base on - which is nice to guess the real parameters of driver.
Anyway, those which provide >1.5A are $20 and higher.
Looking at the components, I'd change Schottky diodes and some tantalum capacitors for better quality.

 

[Katolix]

The type of drive I was thinking of was the 7135 based drivers. Now for a 1050ma driver it takes 3 7135 chips. I will concede one may fail but for all 3 to fail? I doubt it. There is nothing else on the driver board to fail except a diode which I would remove anyway.

The 3 ICs are not qite independent channels. If one fails, it could short-circuit the whole scheme. Also be careful with the diode - make sure it's only for protection from wrong battery polarity.

Anyway my curiosity has gotten the better of me and I have ordered one of these lights. I will post a review soon. But I doubt it will stay stock for long.

Thanks.

 

[Packhorse]

From the pictures it looks identical to the Tilly Tec W30 (300 lumen 3xAAs)...although I assume its not in fact the same given the 162 Euro price tag on the Tilly Tec W30...

upon closer inspection ok maybe not identical but pretty close.

After some googling I find its just a copy.
But. It uses a cree LED and 3 AA cells so the output should be similar, although the TillyTec may use an aspheric lens instead of a reflector in the ultrafire version.
Aspherics will focus the light better with less spill. It may be able to be converted to aspheric.