[selfbuilt]

Rexlight REX 2.1 vs 2.0: RUNTIMES, THROW, OUTPUT, etc - Now with 14500 runtimes!

UPDATE 12/10/07: Kai has finally released the 2.1 upgrade module for the Rex 2.0. With a Q2 emitter and new circuit, with improved performance over the original 2.1 build. Scroll down to the runtimes to find out if this claim holds up (detailed discussion at the end of the post).

UPDATE 12/18/07: It seems the new upgrade module is the same as the new Rex 2.1 002 build. So the results you see below for the upgrade module should be the same for the Rex 2.1-002 currently available for sale.

For a comparison of the Rex 2.1 build 002 to my latest multi-stage 1AA lights, see: Multi-stage 1AA Review - Part III: Runtimes, beamshots & more!.

The lights:

Rex 2.0 on left (black finish), Rex 2.1 on right (natural finish)


Beamshots:

Taken on 2650 NiMH on Hi


Clearly, overall output is reduced on NiMH on the original Rex 2.1. Hard to see in the image, but the Rex 2.1 has much more "ringy" beam than the original 2.0 (as others have noted as well). Also, in real life my 2.1 has a very yellow-green tint to the beam - I'd estimate WG tint at best. Here's a lower exposure to show you the hotspots better:



Haven't done beamshots of the new Rex 2.1 upgrade module for 2.0 yet, as there are some centering issues to be worked out (see discussion at end of post).

Summary Chart for 2650mAh Duracell NiMH



Method: All my output numbers are relative for my home-made light box setup, a la Quickbeam's FR.com method. My relative overall output numbers are typically similar to his, although generally a little lower. You can directly compare all my review graphs - i.e. an output value of "10" in one graph is the same as "10" in another.

Throw values are the square-root of lux measurements taken at 1m using a light meter.

Runtimes:













Key Observations:

UPDATE: See bottom of this post for discussion of results for the Rex 2.1 upgrade module for 2.0

PWM

• If this new Rex 2.1 uses PWM, I can't measure it on my sample. The Rex 2.0 ran at a noticeable 94 Hz.
• UPDATE: Kai claims the new 2.1 upgrade module circuit is current-controlled
• Strobe freq is 9Hz on my Rex 2.1, was 10Hz on my Rex 2.0.

Build Quality & Light Modes

• Build quality is comparable, although the new Rex 2.1 only has one o-ring on the head and tailcap.
• Beam profile of 2.1 is worse than 2.0 - more ringy and non-premium tint bin on mine. Note that throw has not decreased as much as overall output has on NiMH/alkaline, which may explain the rings - looks like they have adjusted the focus for better throw to help offset the lower output.
• Last mode used memory actually works now on my Rex 2.1 on all battery types (the 2.0 would only remember on 14500). Memory is activated after 2 secs now, not 5 secs as on Rex 2.0
• The Rex 2.1 features 3 sets of light states that give you access to different number of modes (see some of the other reviews here for an explanation). It's a bit clunky changing states, but it works.
• See bottom of post for a discussion of the new 2.1 upgrade module for 2.0.

Output vs Runtime

• I'm very impressed with the runtime increases of the Rex 2.1. Although max overall output has decreased slightly on NiMH/Alkaline on Hi and Low, runtime has nearly doubled in all modes. Low runtime is an amazing 2+ days on alkaline!
• Output and runtime have increased on alkaline on Medium, although my graph looks a little wonky. I'll re-test and post the results here.
• Output on Hi on 14500 has increased considerably, now within the range of other lights in this category (e.g. Jetbeam MkIIX, DX X.1, etc), but with litte effect on runtime. The light is not regulated on 14500, but I'm amazed at how long it runs!
• Rex 2.1 is also much brighter than before on Medium on 14500. On Low on 14500, it runs for an outstanding amount of time (i.e. about 3X as long as the DX X.1 for the same output).

Rex 2.1 Conclusions:

• All light modes now work as they are supposed to, on all battery types
• Excellent runtimes on all battery types in all modes now. Outstanding performance on 14500.
• Original Rex 2.1 was a worthy upgrade - only downgrades from 2.0 are in beam tint and ringiness on my sample

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UPDATE: Rex 2.1 upgrade module for 2.0

This module was supposed to fix the problems with the original Rex 2.0, and bring performance up to at least the level of the original Rex 2.1. In fact, this new circuit is apparently identical to what you will find in the new Rex 2.1 build 002, which is an upgrade over the original Rex 2.1

Output vs Runtime

• As you'll see on the updated runtime gaphs, this new module pretty much exactly matches the output of the original Rex 2.1 on 14500, with slightly extended runtimes on low-medium modes.
• On NiMH on Hi, output with this new module has increased to original Rex 2.0 levels, but with longer runtime. NiMH max output was reduced on the original Rex 2.1, so it's good to see max NiMH output of the Rex 2.0 has been retained in this upgrade module.
• Output on lower alkaline modes has increased, which may not be an improvement for everyone. Output on medium is considerably brigther, resulting in lower runtime than the Rex 2.1 (runtime similar to Rex 2.0, but 2-3 times brighter!).
• Output on low on alkaline is closer to Rex 2.0 levels, but runtime is similar to the dimmer Rex 2.1. Very impressive low runtime on alkaline at this level, supporting a considerable improvement in driver efficiency.

Build Quality & Light Modes

• The new Rex 2.1 upgrade module for 2.0 now has all the light modes of the original 2.1 (i.e. daily, tactic, and advanced - cycled through the lowest output state of each).
• Oddly, the emitter star is NOT epoxyed in place on the replacement module, but free floating on the brass pill (i.e. held down only by soldered wires). There does seem to be thermal paste on both my replacement modules, but since the aluminum reflector does not make contact with the emitter, there is no firm pressure holding emitter/star in place. This is likely to cause thermal management issues.
• Centering of the emitter with the supplied replacement reflector is quite off on both my upgrade modules. I suspect this is due to the non-epoxyed nature of the emitter/star on the brass pill. I will try to improve the centering and report back here. As it stands now, both poorly-centered setups lead to a dark semi-circular ring around the hotspot.

Conclusion:

This upgrade module does indeed bring the performance of the Rex 2.0 up to at least 2.1 standards - and even exceeds it a number of ways, as promised. But the lack of epoxy under the emitter star means thermal management issues are now a concern, and centering is rather haphazard (i.e. both of my emitters are noticeably off-center, and others have also reported the same). I would recommend those upgrading take care to properly center and epoxy their replacement modules in place. Other than that, this seems to be a fine upgrade for existing Rex 2.0 users.

UPDATE 12/18/07: Although this new circuit is also used in the new Rex 2.1 build 002, I don't have a sample of that light to directly compare. So I don't know if the emitter is epoxyied on the shipping Rex 2.1-002 - but runtime performance should be the same as shown above.