JetBeam Backup Series (XP-G R5) BC10 & BA20 Reviews: RUNTIMES, BEAMSHOTS, and more!

Originally posted: April 9, 2011
Updated: June 8, 2011

Warning: This double review is more pic heavy than usual.

The Backup lights are a new series from JetBeam, designed with the classic two-stage head twist interface. I will be reviewing the BC10 (1xCR123A) and BA20 (2xAA) models here.

For the sake of brevity, I will use mainly representative body pics from the BC10. More specific pics (including beamshots) will be included with the individual light runtime graphs and summary tables further down this review.

Common Manufacturer Specifications:BC10 Specs:BA20 Specs:

Packaging is fairly typical for these sorts of lights (i.e. simple cardboard box with molded plastic insert). Inside you will find the light, manual, warranty card, wrist lanyard, spare o-rings and spare switch boot cover.

All dimensions given with no batteries installed:

BC10: Weight: 46.6g, Length: 90.3mm, Width (bezel) 23.2mm
BA20: Weight: 70.2g, Length: 156.4mm, Width (bezel) 23.2mm

Scroll down to the individual light reviews for comparison pics to other lights.

The Backup series build is pretty much what you would expect for this sort of family of lights. The components are generally interchangeable among the family (i.e. common threading and diameters for the heads/tails).

On the whole, they look the most like the Fenix LDx0/PDx0 series lights, but a bit bulkier.

Black anodizing (type III = HA) is glossy black, and lettering is a subdued white against the black background (legible and clear, but not obtrusive). Knurling is not very aggressive, but there are some ridge detail items to help with grip.

Tail threads are anodized at the rear end of the battery tube and the tailcap, allowing for lock-out. The lights can tailstand reliably on my two samples.

Clicky switches are the more popular forward clicky type, and look a lot like those found on the recent NiteCore offerings (i.e. silver-plated springs). This later point isn’t that surprising, as Jetbeam and NiteCore are now both owned by the same company. Despite being able to tailstand, I found the switches reasonably easy to access, with a typical traverse and feel.

All lights come with a removable forward-facing pocket clip. Note the clip is not reversible. Clip is fairy basic, but seems sturdy for this type of clip-on model.

The Backup family comes with the Cree emitter XP-G R5 emitter, with light OP reflector. Reflector is fairly deep, so would I would expect reasonably good throw for these lights, with smooth transition to spill. Emitters were all well centered on my samples. Scroll down to my individual reviews for beamshot comparisons to other lights of their respective classes.

User Interface

The UI will feel familiar to users of the classic Fenix LxT series lights – 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.


There was no sign of PWM by eye or instrument, leading me to conclude these lights are current-controlled.

Testing Method:

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.

All my runtime graph 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.


Individual Light Runtime/Output Comparisons


From left to right: CR123A, BC10, Thrunite Neutron 1C, 4Sevens Quark Q123, LiteFlux LF3XT, Zebralight SC50, Sunwayman M10R.

All lights are on Hi on RCR (AW Protected where available), 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.

Note for the Hi mode run, I used an unprotected IMR cell due to the apparent high discharge rate. I would estimate that a regular Li-ion RCR would should off well before 20 mins have passed (i.e. definitely >3C discharge rate), which exceeds safe running specs for standard Li-ion.



From left to right: Duracell AA, BA20, Fenix LD10-R4, 4Sevens Quark AA-2, Sunwayman M20A, Eagletac P20A2-II.

All lights are on Hi on 2x Eneloop NiMH, 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.


Summary of Output Levels

A few observations:

Potential Issues

Initial output on Lo is brighter than the final regulated steady-state level (i.e. typically at two to three times as bright initially). Although variable, drop off in output to the lower regulated level is relatively slow (i.e. not noticeable by eye).

Output on 1x3.7V RCR Li-ion on the BC10 is much higher at both levels, and seems to be direct-drive until the regulated level is reached (shortly before the battery protection cut-offs). Discharge rate on Hi exceeds safe discharge rates for standard Li-ion, so I recommend you use only IMR cells if you intend to run it this way (with standard caveat to be careful not to over-discharge, as IMRs do not have protection circuits). But heat would also be a concern at this elevated Hi level.

Clips are not reversible, and are the less reliable clip-on on style (but seem firmer and stiffer than most of this type).

Preliminary Observations

I’ll get right to the point – the JetBeam Backup lights appear to live up to their impressive ANSI Fl-1 specs, and handle as you would expect for this type of light.

I have a fondness for this kind of simple two-stage mechanism, controlled by head twist (i.e. the classic Fenix LxT series). The build of my two Backup samples are top notch, and the lights seem more sturdy than most. The slightly extra dimensional width also makes it easier to access the slightly recessed forward clicky switch, while still maintaining tailstanding. Switch feel is good. Knurling is not very aggressive, but I found the lights to be a pleasure to handle and use.

I was a bit surprised initially that they seem able to live up to the rated ANSI FL-1 specs (which are impressive for XP-G R5 lights). As my runtimes show, output on Hi is remarkable for both samples – both for the actual output level, and the regulation/runtime. I don’t know how they’ve did it, but these are the brightest XP-G R5 lights I’ve ever seen to date.

Output on Lo is interesting. Both lights start off at higher levels initially (i.e. closer to ~55 estimated lumens), and then slowly drop down to the regulated levels (which are actually closer to ~20 estimated lumens). Although variable on the two modes, the decline is nevertheless slow enough that will you not notice it by eye. As a result, the FL-1 estimates of 30 lumens are a bit on the low side, but not unreasonable (i.e. FL-1 states that output is measured at 3 mins into the run). The regulated ~20 lumen Lo level explains part of why they are able to maintain such extended runtimes. But even at these levels, the efficiency of the lights exceeds what I would expect from a XP-G R5.

The BC10 is direct-drive on 1x3.7V Li-ion, with much greater initial output at both levels (i.e. 470/210 estimated FL-1 lumens, versus of 255/36 on 1xCR123A ). Given the high >3C discharge rate at the Hi level, I strongly recommend you don’t run the light this way on regular Li-ion RCR. You could run it on Hi on an IMR cell, but I also worry about heat build-up at these sorts of drive levels (and with the warning that IMR cells are not protected, so be careful not to run them down).

Beam pattern is good, with a decent sized hotspot with good transition to spill. Throw and spillbeam width are fairly typical for this size light.

Like a number of other “family” series lights, I presume comparable circuits/heads are being used between the 1xCR123A, 1xAA and 2xAA models.

To sum up, the Backup series lights are well-designed, easy-to-use, two-stage lights with a good, balanced beam pattern – but with much higher output on Hi than I’ve seen before for this emitter type. Runtimes are also excellent at both levels, especially on Lo. A nice series of lights at attractive prices, I am sure these will do well for JetBeam.

UPDATE MAY 13, 2011: I have just reviewed the JetBeam BC40 here - a new high-output, XM-L-based, 2x18650/4xCR123A member of the Backup family.

UPDATE JUNE 7, 2011: A user has just reported a 12 min runtime on protected RCR on the BC10, indicating a 5C discharge rate. This is not safe for standard Li-ion chemistry, and should not be used. Only IMR cells can handle these sorts of discharge rates (but the lack of protection circuits means you have to be very careful not to run down the cells, or you will permanently damage them). Be safe.


BC10 and BA20 provided by JetBeam for review.

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

Return to the master review list (at

For a list of all my CPF flashlight reviews in chronological order by battery type (direct link to CPF), please see here:
Candlepowerforums Threads by Selfbuilt

If you are interested in sending a flashlight to me for review, please see my Terms and Conditions here:
Terms and Conditions

For more information on my testing methodology, please see my Methodology section here:
Testing Methodology

Unfortunately, my flashlights are expensive to feed with all the runtime tests I perform. I don't accept any payment for any of my flashlight reviews, but I will gratefully accept donations to my Paypal battery fund. Your contributions will go toward helping defray the costs of creating all my detailed reviews.


For cash donations, please use my personal Paypal account (note that ONLY cash transactions are possible on this account).


For all credit/debit card donations, please use my regular Paypal account.

Page last updated on May 14, 2011 - selfbuilt (at) sliderule (dot) ca (replace the "at" and "dot" labels with the appropriate symbol for e-mail)
All material © 1999, 2011 by Eric Marcotte.