Review: Acebeam L16, a rechargeable tactical light with long throw

This Acebeam L16 was provided by BestLight for review. Use coupon code REDDIT for 10% off most lights.

A full album with extra images is available at http://imgur.com/a/ftzK8

Quick Review

The L16 is Acebeam's new entry into the long-throwing duty light segment, competing closely with the likes of the Klarus XT12GT. It runs on a single, standard 18650 battery (included) and has a MicroUSB port for onboard charging. The target market appears to be first responders, however the L16 is suited to anyone who needs a light with some reach combined with foolproof operation when under pressure. I hate the profilic use of the T-word in marketing, but it's actually fair to call the L16 "tactical", which, unsurprisingly, Acebeam does.

http://imgur.com/4HqVa4N.jpg

I had initially expected the L16 to be a dedicated jacket-pocket size thrower that isn't especially useful at shorter distances, but the hotspot is larger, and more of the light goes to the spill than I would have guessed. While I wouldn't recommend the L16 for a use case that's primarily indoors or in a dense forest, it's it's well suited to general use in more open spaces. Unfortunately, the beam is a very cool tint, between 6500 and 7000K. It's a pure white without the rainbow effect of off colors found in many domed Cree emitters, but the tint is fairly harsh to my eyes. More objectively, the light of the L16 washes out colors, making details harder to see and has significant backscatter when the air is not clear, which would be lessened with a warmer tint. I think a 4000K tint would be ideal for this light's intended use case.

  • L16: http://imgur.com/8saHza3.jpg
  • For comparison, a neutral white Astrolux SS, considered to be more of a dedicated pocket thrower: http://imgur.com/GT2BnfS.jpg
  • And a floody light, the Klarus G30: http://imgur.com/dqW0oNe.jpg

The user interface isn't the typical dual-switch configuration, but more like two lights in one. The tailswitch is a forward-clicky with half-press for momentary and always locks the light in its highest mode no matter what it was doing before. Releasing or toggling the tailswitch off always turns the light off, no matter what it was doing before. It's a foolproof one-mode light with momentary. With the side switch, it's a well-designed e-switch light. From off, hold for low, double-click for high or short-click for last-used. When on, hold to cycle in order of increasing brightness. Triple-click for strobe, if you must. A short click from on is always off. This is my favorite solution yet to the probelm of designing a light that's both versatile in terms of output levels, but foolproof under stress.

The construction is solid, typical of Acebeam in my experience. I was particularly impressed by how well the USB port cover keeps out water, a point of concern with some users when it comes to onboard-charging lights. There are springs at both ends of the battery tube which allow the use of all 18650s, protected or unprotected, flat or button top. In addition, the battery tube has a shoulder at the front, preventing the battery from bouncing against the driver board if subjected to severe shocks. Acebeam claims the L16 is suitable for weapon mounting, and this feature is very appropriate to that use case.

The L16 didn't quite hit its advertised numbers in my testing, measuring 1700 lumens and 515m throw to the advertised 2000lm and 603m. This came as little surprise to me as single Li-ion lights using the XHP35 emitter very rarely perform as advertised. The similar Klarus XT12GT also claims 603m throw and fell short by almost exactly the same amount when zeroair reviewed it. Using the XHP35 requires boosting voltage from the 3.0-4.2 of the battery to around 12.0, which is difficult to do at high power levels efficiently. Runtime suffers as a result, and the light can't quite maintain stable output on its highest mode when cooled, though it's more likely to get hot and drop to 45% under typical conditions. That's still about 400m FL1 throw and a useful amount of light that can be maintained for an hour. I think an efficiency hit like this would have been better spent on color quality; a 90 CRI 219C can also make 1000 lumens from 4.4A, but lumens sell lights and the XHP35 HI can make more of them, briefly.

People who aren't picky about tint and color rendering will like the L16 as it comes. It's a solidly-built, all-inclusive package with a perfect UI for the application, but a 4000K emitter would greatly improve it. That will have a bit less output, of course, but human eyes don't perceieve brightness linearally and most people would struggle to tell the difference without instruments.

    • Innovative user interface blending versalitily with foolproof operation
    • Useful spill and large hotspot for the amount of throw
    • Heavy-duty construction
    • Good waterproofing
    • Nice holster
    • Very cool tint
    • Falls short of advertised performance
    • Poor efficiency
    • Unsophisticated thermal regulation
    • Side switch is difficult to find by feel
    • Slightly high standby current

Details and technical analysis

Accessories

The L16 ships with the following:

  • Holster
  • Acebeam branded protected 3100 mAh high-drain 18650
  • USB cable
  • Pocket clip
  • Grip ring
  • Lanyard
  • Spare O-rings
  • Spare switch boot
  • User manual
  • Warranty card

The holster is of better quality than I'm used to seeing included with lights, and I've read elsewhere that Acebeam's 3100 mAh battery is believed to be a Sony VTC6. It is protected, but able to handle the high load of the L16, while some other protected batteries I tried tripped.

http://imgur.com/MoLrbt7.jpg

http://imgur.com/5Bm2RB5.jpg

Modes and user interface

Activating the tailswitch always results in turbo, from off or on. A half-press is momentary and a full press is toggle. Deactivating the tailswitch always turns the light off, even if it had been turned on with the side switch. As to the side switch:

State Action Result
Off Short click Memorized mode (last-used other than turbo or strobe)
On (any, unless tailswitch is on) Short click Off
Off Long-click Firefly
On (any, unless tailswitch is on) Long click Cycle through modes in l->h order
Any Double-click Turbo
Any Triple-click Strobe

There is no sign of PWM on any mode.

Output and runtime

All tests were conducted with an LG HG2 3000 mAh 18650 battery unless otherwise noted.

Mode Advertised Lumens Estimated Lumens Throw (FL1 meters) Graph Advertised Runtime Time to 80% Time to 50% Time to 10% Tailcap current (mA)
Standby 0 0 0 - - - - 2.8 years 124 microamps
Firefly 1 1 0 - 500 hours (21 days) - - 439 hours ( 18 days) 6.84
Low 150 131 140 - 9 hours - - 9 hours 330.5
Mid 500 460 267 graph 132 min 153 min 153 min 153 min 1460
High 1000 1016 399 graph 72 min 48 min 48 min 48 min 4400
Turbo 2000 1700 515 graph 66 min 20 min 23 min 23 min -

Additional graphs:

The 4.4A required to produce 1000 lumens is about 50% more than an XP-L needs, though the runtime test got a bit more out of it than the current draw would have predicted. Advertised runtimes are likely uncooled, and the L16 gave me 68 minutes to 10% on turbo without cooling. While I'd prefer that manufacturers be clear about that when a light has a thermal sensor and can have its runtime affected significantly by environmental conditions, I'm pleased that the advertised runtime was accurate.

The light's built-in low voltage protection trips at 2.35V. That's not ideal, but a warning blink starts at about 3.0V and a prudent user will heed it. 2.35V will not cause serious damage to a battery as long as it isn't done regularly and the battery is charged reasonably soon after.

Ergonomics

The L16 feels lightweight and comfortable in the hand. Different surfaces are textured differently, but all provide acceptable grip. The tailswitch is proud and easy to press with a moderate amount of travel required to lock it on. Using momentary is easy for me. The side switch, on the other hand is flush and a bit difficult to find by feel. I find myself just feeling for a flat area, not a switch.

There's a grip ring installed on the light from the factory. It screws off, but won't slide over the O-ring; removal requires removing the O-ring first. It's mainly intended for using the light in conjunction with a firearm, which I tried and found uncomfortable. Maybe I'm not tactical enough.

I tried using the pocket clip and found that uncomfortable as well. I don't think it's meant to be used regularly due to the light's width, but the L16 can be securely carried in a larger pocket using the clip.

Size comparison: Astrolux SS, Acebeam L16, Zebralight SC62w, Fenix TK25 R&B, Nitecore EC4

Battery and charging

The included battery is a 3100 mAh protected cell. I've seen it suggested that this is a Sony VTC6. Its performance appears comparable, anyway. All 18650 batteries tried worked in the light regardless of flat or button tops and protection or lack thereof. Some protected cells, however tripped in turbo mode. Cells rated for 10A or more should be used for both safety and performance, as the light does not appear to make a significant attempt to reduce output. Two CR123s can also be used, but output and runtime will be reduced.

Charging takes 4 hours with an HG2 that was run down to the light's LVP, a 2A power supply and the included Acebeam USB cable.

Modification potential

I've decided to start including modifications in reviews. Some people just can't leave well enough alone, and I'm one of them. The bezel is easy to remove and installing another 12V emitter should be very straightforward. I have the 4000K XHP35 HI I've been saying this light needs, but other 12V emitters like the Cree XHP50 and XHP50.2 on an appropriate MCPCB or the Nichia 144AR could be used without the original centering ring.

http://imgur.com/NlMyjht

I ordered this XHP35 HI in 4000K, 80 CRI from Kaidomain. I could have gone for a decent 5000K tint with about the same output as the original, but I thought the backscatter would be better at 4000K, and I wanted to see if my usual preference to trade output for CRI held up in a longer throwing light.

It did, I think. I can see better with the warm L16 than with my 5000K, unspecified CRI Astrolux SS, which has similar throw, and now isn't too far behind in output. Those numbers, by the way:

Mode Lumens Throw
2 115 152
3 393 246
4 831 358
5 1340 459

The tint reminds me a lot of a 4000K Nichia 219C. It's not coppery like the warm Wizard XHP50 nor rosy like a 219B, but a little bit yellow. There's no significant green or tint shift across the beam. Overall, I'd call it pleasant. Color quality is good, but things don't quite pop like they do with a 90+ CRI emitter. It's still helpful at a distance, and I wouldn't give up the improved color quality to restore the original output even in this tint were that option available. At a minimum, every percent change in CRI is worth 3% output to me, possibly more.

I wouldn't be keeping this light if I couldn't swap the emitter, but I like it a lot now.