JetBeam Backup BC40 (XM-L) High-Output Review: RUNTIMES, BEAMSHOTS, and more!

Originally posted: May 14, 2011
Last updated: June 8, 2011

Warning: pic heavy, as usual.

JetBeam has recently added a high-output 2x18650 light to its Backup series – a family of inexpensive, two-stage lights. Let’s see how it compares to the pricier competition in the high-output world …

Manufacturer's Specifications:

Packaging is similar across the Backup line (although the inviting "Try Me" is new ). Inside the cardboard box, you will find the light (sandwiched inside a molded plastic insert), manual, warranty card, wrist lanyard, grip ring, spare boot cap and o-rings. A well-fitting belt holster was also included with my sample.

A very good package for a "budget" high-output light.

From left to right: Redilast Protected 18650, JetBeam BC40, Lumintop TD-15X (2 extenders), Thrunite Catapult V3, JetBeam M1X (no extender), Olight M31 (no extender)

All dimensions are given with no batteries installed:

BC40: Weight: 226.3g, Length: 224mm , Width (bezel): 48.5mm
Catapult V3 XM-L: Weight: 434.8g, Length: 254mm, Width (bezel) 58.0mm, Width (tailcap) 35.1mm.
TK35: Weight: 256.1g, Length: 162mm, Width (bezel): 48.6mm, Max Wdith 52.0mm
M3C4 XM-L: Weight: 348.0g, Length: 164mm, Width: 61mm (bezel)

As you can see, the BC40 is one of the lightest lights in this class. Overall dimensions are also quite compact for 2x18650 light (batteries end-to-end).

First, a few comments about the holster - I quite like it. It is simple, easy to use, and even has a velcroed flap for attaching around a belt. Considering the extremely low price, it's remarkable they included one at all.

UPDATE May 29, 2011: Some users have reported receiving the light without the holster. Recommend you confirm with your dealer, if it matters to you.

The body plan of the BC40 is fairly straightforward. Overall, I find it reminds me of the classic Streamlight Strion/Stinger shape. I found it comfortable to hold and handle.

Black anodizing (manufacturer claims type III = HA) is slightly glossy, and without blemishes on my sample. Lettering is clear and sharp, and reasonably bright.

The light lacks knurling (except for a small band around the bezel), and instead has a series of thick-cut concentric rings around the body. Looks reminiscent of some McGizmo designs - but is quite basic here. These rings help a bit with grip, but I still find light somewhat slippery overall.

Screw threads are square-cut (well, trapezoidal) and anodized at the tailcap, to allow for lock-out.

Switch is a forward clicky, of similar design to other lights in the Backup family (and some recent NiteCore lights). The BC40 can tailstand.

Like all members of the Backup family, there is a physical reverse polarity device (plastic disc) in the head. But it would seem to be circumvented on the BC40, given there is a spring located in the center of it. Higher capacity flat-top cells worked fine in my testing.

I didn't find the bundled grip-ring very useful. You just drop it on at the tailcap region, where it spins freely (even with the tailcap tightened). Somewhat useful as an anti-roll device, but I don't imagine too many would use it as an actual grip aid.

EDIT: As HIDBlue suggests below, adding an extra o-ring between the grip ring and the tailcap provides enough contact pressure to stop it from spinning.

The BC40 uses a Cree XM-L emitter, with a medium-heavy OP reflector. I would expect throw to be no more than average for the class, given the medium-sized head and OP reflector.

Although at first glance, the head seems to be sealed. However, MountainMike confirms that he was able to open his with strap wrenches.

And now the white-wall beamshots. All lights are on 2xAW protected 18650, about ~0.75 meter from a white wall (with the camera ~1.25 meters back from the wall). Automatic white balance on the camera, to minimize tint differences.

Beam pattern is good – the light has a reasonable amount of throw, and a nice transition from spot to spill.

UPDATE June 6, 2011: I have just posted a new 100-yard round-up beamshot review for 2011, showcasing all my current "thrower" lights. Below are a couple of an animated GIFs showing some relevant comparisons for the BC40. Please see that round-up review for additional pics of other lights, taken under the same conditions.

User Interface

The UI is the same across the Backup family – twist the head tight for Hi, loosen for Lo.

Turn on/off by the forward clicky switch (i.e. press for momentary, click for locked-on).

And that’s it. No strobe, SOS, etc.


Unlike the other members of the Backup family, the BC40 uses PWM on its low mode, measured at 876 Hz on my sample. This is high enough to not be overly distracting in regular use, but it is detectable.

Testing Method:

All my output numbers are relative for my home-made light box setup, a la Quickbeam's method. You can directly compare all my relative output values from different reviews - i.e. an output value of "10" in one graph is the same as "10" in another. All runtimes are done under a cooling fan, except for any extended run Lo/Min modes (i.e. >12 hours) which are done without cooling.

I have recently devised a method for converting my lightbox relative output values (ROV) to estimated Lumens. See my How to convert Selfbuilt's Lighbox values to Lumens thread for more info.

Throw/Output Summary Chart:

Effective November 2010, I have revised my summary tables to match with the current ANSI FL-1 standard for flashlight testing. Please see for a description of the terms used in these tables.

No surprises on Hi - the BC40 performs in the same range as most lights of this class, both for overall output and for throw.

Lo output level is reasonable for a two-stage light. Note that it is not as low as most multi-level lights in this class.

Output/Runtime Comparison:

Output and runtime on Hi are right in keeping with this class. On both 2x18650 and 4xCR123A, the light performed exactly as expected.

On Lo, runtime was a little low compared to some other lights. Still quite reasonable, but not as effiient as the TK35 for example.

Potential Issues

The light lacks any real knurling, and can be somewhat slippery to handle.

The light uses visible PWM on the Lo mode, but the frequency is high enough to not be overly distracting - 876 Hz. However, output/runtime efficiency on Lo is not as high as other lights that use current-control.

Lo output level is reasonable for a two-stage light, but not as low as the multi-level competition.

Preliminary Observations

I am impressed with how much light you get with the BC40 for the price.

No, you don't have all the levels of most of the competition. But you do get reasonably well-spaced levels, with a simple two-stage head-twist interface. In some ways, you could think of the BC40 as a slightly smaller and more streamlined version of the original Catapult V2 XM-L (but with less throw due to the smaller reflector, of course).

Despite the budget price, there is nothing budget about the quality of this light. Like the rest of the Backup family, the build seems of high quality. No, it doesn't have all the flourishes of the regular JetBem lights, but the minimalist ethic of the Backup series is well implemented (and suitable for a high-output light, IMO). That being said, I would like to see a little actual knurling on the body tube.

Like the other members of the Backup family, I found the switch easy to access (despite being recessed for tailstanding).

Beam pattern is good - well-balanced, with a good mix of spot/throw to spill. Emitter tint was good on my sample (i.e. a premium Cool White, with just a hint of purple). But as always, YMMV - I would expect greater tint variation on a "budget" light.

Output and runtime on Hi are right on the money for this class - no surprises. Runtime on Lo was a bit low (especially compared to the always-efficient Fenix offering in this space), but still reasonable. Unfortunately, the light uses visible PWM for the low mode, but I didn't find it distracting in use (i.e. freq is 876 Hz).

If all you are looking for is a simple two-stage High-output light, I don't see how you could do better right now for the price. The light even comes with a decent holster! While there are still a few areas for potential improvement (as with any light), in my opinion the BC40 is a fantastic bargain in this space at the moment.

UPDATEs May 29, 2011: Contrary to what I previously reported, the BC40 does use PWM for its low mode - measured at 876 Hz on my sample. Also, one CPFer reports being able to open the head with strap wrenches. And a number of members report that their lights came without holsters.

BC40 provided by JetBeam for review.

To follow the online discussions for this review, please see the full review thread at CPF.

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