Review: Acebeam L17 (18650, White Flat, compact TIR thrower)

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maukka
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Review: Acebeam L17 (18650, White Flat, compact TIR thrower)

Disclaimer: I received the Acebeam L17 free of charge from the manufacturer (affiliate link, non-tracking link)

The Acebeam L17 is a compact thrower utilizing the tiny Osram White Flat LED (2mm²). A TIR optic focuses the majority of the light to a bright spot and minimizes the amount of light wasted on the spill. Electronic soft touch tail switch is silent, but some tactical features such as a momentary turbo or strobe are missing. Output and throw don’t quite reach the manufacturer’s claims, but a constant current driver with good efficiency and excellent build quality make the L17 a great option for a mini thrower with a competitive price.

If you’re here only for the numbers, here they are:

Manufacturer’s specifications
Battery: 18650 lithium ion or 2xCR123A primaries (USB rechargeable 18650 included)
LED: Osram White Flat, cool white, low CRI
Water and dustproof: IP68 waterproof to 5 meters
Impact resistance: 1 meter
Mode memory: yes (3 basic modes)
Low voltage protection: yes
Thermal regulation: yes
Lockout: software, physical
Tripod socket: no
Tailcap magnet: no
USB charging: in the battery

Manufacturer’s output specs
Ultralow: 15 lumens, 3600 cd, 120 meters, 58 hours
Low: 50 lumens, 11025 cd, 210 meters, 21 hours
Mid: 150 lumens, 23409 cd, 306 meters, 6 h 45 min
High: 370 lumens, 42025 cd, 410 meters, 2 h 45 min
Turbo: 1400 lumens, 160801 cd, 802 meters, 1 h 15 min

Please note that the specified lumen and throw numbers don’t make any sense as they aren’t linear. For example, if the high is 370 lumens and mid is 150 lumens, the difference should be identical on throw, but it isn’t. 370/150=2.467, but for throw 42025/23409=1.795. This is the first sign that the numbers aren’t to be trusted.

Measured dimensions and weight
Length: 140.5 mm
Handle width: 25.3 mm
Tail width: 28.0 mm
Head width: 40.0 mm
Weight: 146 grams, plus 49g for the battery

Box and contents

Bundled in the box with the light:
Operating intructions
Holster
Lanyard
Two spare o-rings
Spare switch boot
Warning leaflet and warranty card
3100mAh 18650 battery with USB charging
Micro-USB charging cable

Physical appearance


A second tube carries the e-switch signal to the driver.


Cigar grip ring can be removed. This leaves a small gap on the body.


Switch signal and battery negative connect via a tab on the tailcap.


Larger image
Driver at the head


Switch signal tube is narrower at the head. You can’t insert the battery from this side.

Battery

The Acebeam L17 comes with a 3100mAh 18650 battery. It has a Micro-USB port for charging. The cable and the fact that the battery reads “in/out” makes it look like the battery can also be used as a powerbank but this isn’t the case.

Battery model number is ARC18650H-310A with a specified capacity of 3100mAh or 11.2Wh.

Capacity of the Acebeam battery was measured at 1A discharge down to 2.5 volts
2867mAh, 10.291Wh

This data was used to calculate the flashlight efficacy.

Integrated charging

The battery has an integrated charging circuit together with the protection PCB.

It takes about 2 hours and 39 minutes to charge the battery using the Micro-USB connection. Maximum current draw from the USB port is

User interface

The light is operated via an electronic tail switch. The soft touch switch is silent and easy to use with gloves. It feels very good.

Operation is simple.
From off
Single click to turn on the light (mode memory)
Long press for ultra-low mode
Longer press for software lockout (unlock with 5 second press, light turn on ultra-low)
Double click for turbo
Triple click for strobe

From on
Single click to turn off the light
Hold to cycle modes (low-mid-high-low-…)
Double click for turbo (another double click to return to previous mode)
Triple click for strobe

When the battery voltage is low, the light exhibits some erratic behavior. After the light has blinked three times to indicate a low battery (this happens <3.3V), the lockout doesn’t work from off with a 3 second press. The light just flashes a couple of times and after a while it stays on and locks permanently on until you unlock with another 5 second press. Secondly, the ultra low mode access from off doesn’t work correctly. The light first turns on at a higher mode and only then turns down.

edit 2020-09-15: Above bug of the first review sample is fixed. On the new version turbo stops working when idle battery voltage reads 3.35. There’s no sign of UI bugs anymore after the low battery indicator has initially activated. Lockout and ultralow mode works fine and modes are cycled normally.

User manual:

Beam and tint
Acebeam says the light uses a Carclo TIR optic with the Osram White Flat LED. A hotspot size of less than 4 degrees and a candela to lumen ratio of 104 means the beam is very throwy, similar to lights with much bigger reflectors. The hotspot produced by the TIR optic is very well defined. Spill gradually dims towards the edge of the beam so it’s not as distinctive as on reflector lights.

Here’s the beam compared to a similarly throwy Emisar D1S which has a bigger head with a reflector and an XP-L HI emitter.

Zoomed in

There’s a slight greenish and warm corona around the hotspot. It didn’t really bother me in use.

Tint depends heavily on the brightness in use. Turbo is clearly cooler and more magenta in tint than the lower modes, which indicates a slight overdrive.

Spectral data and color rendering
For spectral information and CRI calculations I use an X-rite i1Pro spectrophotometer with HCFR, Babelcolor CT&A and ArgyllCMS spotread for the graphs and data. For runtime tests I use spotread with a custom script and an i1Display Pro because it doesn’t require calibration every 30 minutes like the i1Pro.

Explanation of abbreviations

If you have an hour to spare, I recommend watching this presentation on IES TM-30-15 which also shines light into color rendering in general.

Color rendering overview on different output modes measured from the hotspot.

CRI data on turbo with Li-Ion measured from the hotspot at 10 seconds:

CRI data on other modes
High
Mid
Low
Ultra-low

Output and runtimes

Output is perfectly regulated on all modes. Temperature limit restricts the output on turbo. There’s no hard stepdown, rather the output drop gradually while getting hotter. The light draws over 7 amps from the battery on turbo. Despite the very small emitter efficiency is ok thanks to the constant current driver.

The light can sustaine 558 lumens on turbo after stepdown. High is perfectly regulated at 344 lumens for two and a half hours until the low battery warning drops it to low mode at 49 lumens.

I can’t really justify criticizing the rather high sounding ultra-low mode. A thrower like this isn’t ideal for searching items in your tent in pitch black anyway.

I didn’t do a runtime at the lowest level, but measured the battery power draw with a PSU at 146.8 milliwatts at 4 volts. Thus the included battery should provide a runtime of roughly 76 hours.

Almost full turbo output is available even at a half discharged battery. When the battery level drops below 3.3 volts, the light automatically switches to the 50 lumen low mode.

Standby drain
There’s hardly any parasitic drain even with the electronic switch. However, engaging the software lockout increases the drain almost 10-fold. Although at under 1mA this isn’t a huge issue. I’d still recommend opening the tailcap half a turn instead.

Standby current
85µA
In lockout mode: 751µA

Flicker
Using a true constant current driver, there’s no PWM or visible flicker at all. Some insignificant ripple at high frequency is evident on the scope, but that shouldn’t show up on video or photos. Flicker snob index is 0%.

Worst case flicker on the lowest level:

Other modes:
Turbo
High
Mid
Low

Temperature
The Acebeam L17 has temperature regulation to protect the LED, electronics and battery. On turbo in 25°C room without airflow the surface temperature reached a whopping 74°C. This will burn you so please don’t leave the light unattended near children or pets. On high the maximum temperature I measured was an easily hand holdable 42°C.

Verdict
The Acebeam L17 is a compact but capable thrower with a pencil like beam. It offers better throw than many bigger lights with reflectors. Most of the light is tightly concentrated to the spot with minimal spill, thanks to a small Osram White Flat LED and efficient TIR optics. Excellent build quality, ease of use and good efficiency make it a premium flashlight for a reasonable price. You can easily use more than half of the supplied 18650 battery and still get nearly full output on turbo.
While CRI isn’t the highest necessity for a thrower, unfortunately there’s no neutral or warm white option for the White Flat. In some cases targets might seem a bit washed out especially on turbo, when the color temperature is quite cool. On high the perceived tint is most pleasing, while the lower modes seem a bit greenish in tint. On turbo on the other hand the LED is driven very hard which makes for a slightly magentaish tint. The surface temperature will also be very hot after a couple of minutes.
The L17 is a pleasure to use and will surely impress most people with its performance, even though the output of my sample didn’t quite reach the manufacturer’s claims. Acebeam advertises the light as tactical, but there’s no momentary turbo or strobe. The usual Acebeam UI is very intuitive though.

+ Great throw for the size
+ Excellent build quality
+ Most of the light is concentrated on the hotspot and not wasted on spill
+ Smooth and silent switch
+ Fully regulated output
+ Maximum output available with a partly discharged battery
- Only available in cool white
- Tint changes a lot depending on mode
- Slight greenish corona around the hotspot
- Gets very hot on turbo
- Doesn’t reach advertised output or throw
- Lockout mode increases standby drain by a factor of 10
- No momentary turbo or strobe
- Bugs when light enters low voltage mode (supposedly fixed, will verify soon) FIXED

If you wish to purchase this light and support my work, consider ordering it from Acebeam.com using my affiliate link below, which gives me a small cut (5%).
Acebeam L17

Edited by: maukka on 09/15/2020 - 12:35
Anthon
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Thank you a lot for your review maukka, it’s always a pleasure to read

I think it’s a good try for Acebeam for developing new things, but in this case I think that this light is worse than a L16, almost half lumens and same throw but without onboard charging, without momentary turbo and without the ability for a NW led (xhp35’s NW are still easy to find)

cleo_stary
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Excellent review. Thanks a lot for your hard work, Maukka.

We got this product, too.

Please check here if anyone else is interested in this product.

Rayoui
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Thanks for the comprehensive review. I was thinking of picking this one up, but the firmware bugs and inadequate temperature regulation give me pause.

Anthon
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cleo_stary wrote:
Excellent review. Thanks a lot for your hard work, Maukka.

We got this product, too.

Please check here if anyone else is interested in this product.


Is the firmware bug solved in your stock units?
cleo_stary
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Anthon wrote:
cleo_stary wrote:
Excellent review. Thanks a lot for your hard work, Maukka.

We got this product, too.

Please check here if anyone else is interested in this product.


Is the firmware bug solved in your stock units?

Yes, of course. Brand new, in stock.

LumenLucas
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Great review as always, very informative

Anthon
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I’ve just received this light from Nitetorch and I can confirm that the low battery bug is solved, I’ve tested even at 3.1v and I can lock it and start at lowest mode

The wrap from the cell included in my light shows a date: 2020/08/13

Sirstinky
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Great review. The low battery bug wasn’t present on my sample, but my results are similar to yours. I only got 694 m of throw by my test at 30 seconds, but got 716 m at 5 seconds. I can attest the regulation is very good despite the led is being driven pretty hard as well. I recorded 64 C at around 2 minutes before the step down.

man of light
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Great review maukka, very detailed and informative with excellent pics and beamshots Thumbs Up good job.

The light itself is unfortunately a rather uninteresting product.

.. .-.. --- ...- . ..-. .-.. .- ... .... .-.. .. --. .... - ...

Lumeniac
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thanx for great review again

i habe green led version, soon will post comparasion of green vs white

my impressions are the same - that is really good thrower

 

 

 

Majoroverkill
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Can you use other 18650 cells or just Acebeam cell?

Doug S.

Sirstinky
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My regular fat top 18650 didn’t fit great, but did work. They rattled in the tube quite a bit. Protected or buttom top recommended.

Majoroverkill
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Sirstinky wrote:
My regular fat top 18650 didn’t fit great, but did work. They rattled in the tube quite a bit. Protected or buttom top recommended.
Thumbs Up Thanks for the info Big Smile

Doug S.

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Nice review Maukka! I hope to be finished with my review of the green L17 soon. I am really impressed about the TIR lens Acebeam uses here.

 

 

SKV89
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Output measured at 2 seconds from turn on using Texas Ace Lumen Tube calibrated with Maukka lights. Color measured using Sekonic C-800-U.

Acebeam L17 Turbo 1,141 lumens 7110K -0.0042 DUV 70.7 CRI Blue light relative amplitude 1.00 -12.6 R9 42.2 R12 64 Rf 96 Rg VTC5D
Acebeam L17 High 293 lumens 6200K 0.0037 DUV 66.9 CRI Blue light relative amplitude 1.00 -36.9 R9 36.3 R12 63 Rf 95 Rg VTC5D
Acebeam L17 Mid 131 lumens 6012K 0.0056 DUV 67.0 CRI Blue light relative amplitude 1.00 -39.9 R9 34.9 R12 64 Rf 94 Rg VTC5D
Acebeam L17 Low 40 lumens 5769K 0.0081 DUV 66.9 CRI Blue light relative amplitude 1.00 -45.0 R9 33.0 R12 65 Rf 93 Rg VTC5D
Acebeam L17 Moonlight 9 lumens 5403K 0.0109 DUV 66.5 CRI Blue light relative amplitude 1.00 -49.2 R9 31.2 R12 66 Rf 92 Rg VTC5D


The light is huge for an 18650. It is larger than most 21700 lights. For this size, I don't understand why Acebeam didn't just make it a 21700 light? I like how with this optic, the spill gets dispersed evenly so the hotspot stands out more than from a reflector light.

maukka
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Acebeam told me they have fixed the issues with low battery voltage. Will verify as soon as I get the fixed version.

Majoroverkill
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maukka wrote:
Acebeam told me they have fixed the issues with low battery voltage. Will verify as soon as I get the fixed version.

I look forward to your findings. I am very interested in the L17. I have been reading the H30 has it’s problems to, only allowing the cell to drop to 3.7V with any cell before LVP kicks in.

Doug S.

maukka
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I received a new sample with an improved firmware. On the new version turbo stops working when idle battery voltage reads 3.35V. There’s no sign of UI bugs anymore after the low battery indicator has initially activated. Software lockout and ultralow mode work fine and modes are cycled normally. I consider the problem fixed.