Acebeam P18

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Acebeam P18 review

Acebeam P18 specs

Brand & ModelAcebeam P18 Defender
Flashlight categoryTactical Use, General Purpose
LED4*Luminus SFT-40-W
Max. output5000 lumens
Max. beam distance629 meters
Max. beam intensity98,910 cd 
Battery config.1*21700
Onboard chargingUSB type C
BlinkiesStrobe, S.O.S
Review publication dateFebruary 2023

Review intro:

Hot on the heels of the Acebeam P17 Defender review comes its bigger sibling, the P18 Defender. As the name implies, this is a bigger, more powerful version of the latter light in the series, and of course it brings all of the requisite Acebeam-centric qualities and pleasantries I’ve come to enjoy and (expect).

However, this one marches to the beat of a different drummer. The P18 is a quad LED configuration and I can more or less count on one hand the number of true tactical-use lights sporting multiple LEDs for a reason: Generally, multiple LEDs generate more heat, use more energy, and are harder to drive efficiently. Even though battery tech has come a long way, a single cell is not the best, nor most efficient way to drive multiple LEDs.

This can be an issue because professional users require a light that can stay bright for long periods without stepping down the output while delivering long runtimes. Moreover, multiple LEDs become multiple failure points and add unnecessary complexity. In short, one could venture in the opinion that professionals don’t need small lights with multiple LEDs…or do they? I was surprised to see Acebeam release this light since it seems a bit superfluous and unnecessary in this segment, but have they created a useful and practical multi LED tactical use light? I hope Acebeam can prove me wrong here. There’s some good features present including onboard USB type C charging and some pretty decent performance specs.

Package quality.

The P18 enjoys the same packaging improvements as the P17. The plane-Jane thin paper boxes have been replaced by more upscale packages. and themes. I like the new package, and it’s more appropriate for the asking price of this light. The contents sit in soft touch medium density foam that looks luxurious and everything’s neatly organized. Here’s what you get:

  • Acebeam P18
  • USB A to C charging cable
  • User manual
  • Warranty documentation
  • Acebeam-branded IMR21700NP-510A 21700 battery (in the light)
  • Spare o-rings
  • Marketing insert for the X75

Unfortunately, there’s no lanyard or holster (again), but the battery is included, so that’s nice. Acebeam’s batteries are high quality (and expensive). The same way-too-short USB cable is present, and while it’s a high quality cable, I really wish Acebeam would include a longer cable.

Flashlight in use

The P18, like the other P series lights, was designed with a single mission: Tactical-use. While I’m skeptical of the efficacy of a multi-LED pocket light for tactical use, we’ll see how this one pans out. In my time with the P18, I’ve found it to be a great general purpose flashlight. 

Handling-wise, for a 21700 size duty light, it’s a great fit for my hands, and it feels and handles very intuitively like the P17. The design is very flashlight-y with extra deep cooling fins behind the head and gripping surface.

The controls are out back, with the removable tailcap featuring a dual-switch arrangement. The tailcap as well as the body has lots of groves and texturing for a super secure grip and the tube is short enough to use one-handed, which is critical in true tactical use lights especially in law enforcement when a free hand might be preoccupied with other tasks.

There’s a blackened stainless removable dual-position pocket clip, and it’s held on very securely, but comes off with some persuasion. Unlike the P17 tailcap, the P18 has no lanyard holes in the tailcap, and that’s a shame. You could mount a lanyard to the pocket clip though. As far as carry options, this light is pocketable, but just barely due to the 50 mm head. You could do a cargo pocket, but for regular pants, (unless you go MC Hammer with the parachute pants) it’s too big. 

The way Acebeam packaged the charge port is a near mirror-image of the one on the Fenix TK20R V2, but it’s larger, and integrated to the point you wouldn’t know this light has onboard charging if not for the markings on the cover. It’s a twist-to-retract collar that unscrews to expose the USB-type C port. This is a far superior design to a standard rubber plug since it won’t unintentionally open and is much more durable and robust. It opens wide enough for a large USB connector and under the collar is a single LED indicator for charge state.

However, if fully unseated, it will flop around loosely on the battery tube. It is captured so it won’t come off, but I don’t like how it’s loosey-goosey.It also took 5 full turns to unscrew and requires a bit of effort to do so, and I’m glad there’s some grippy grooves to help out. The switches are carried over from the P17 and consist of a large round switch and a smaller, paddle type switch.

The bigger switch (the Tactical switch) is a forward clicky, and the smaller one (the Functional switch is an e-switch for momentary use only. Each can operate independently to control different functions and the three mode groups. The switches feel good, but I felt like they could be a bit more clicky and snappy. The Tactical switch has a very proud boot that has about 2.5 mm of give to it before engaging the switch button, and requires a decent amount of effort. Good for accidental activation, but it detracts from the overall feel of the switch even if the clicks are positive and audible.

The Function switch has a rigid plastic texture, but I wasn’t crazy about how it felt during use. It requires direct pressure to activate (again, good to avoid accidental activation), but it requires careful manipulation to activate. Presses that weren’t mostly directly over the button wouldn’t activate the light. Under stress, this could be an issue. The important thing here is both switches could be activated one handed with my thumb, an important feature for a light like this. Tail standing is a no-go.

Build Quality and Warranty

It’s no secret that Acebeam makes exceptionally high-quality lights with excellent fit and finish and quality control. The P18 is more of the same, and the price reflects this, with an MSRP of around $130. The price isn’t so much of an issue here though and it’s competitively priced in this segment.

The P18 borrows a lot of design cues from the P17. It is milled from high quality 6061-T6 aircraft aluminum. I feel like a broken record here with Acebeams since it’s perfectly done with no blemishes, tool marks, or burrs. All the edges are knocked down and there’s no gaps anywhere. Typical Acebeam stuff. The anodizing is classified as type III HA, and I’d put money down it’s going to be close to the true MIL-A-8625 spec thickness (0.0005 to 0.0030 inches). It’s black and it’s one of  my favorite finishes with a nice grippy satin feel to it. The coverage is even and flawless. The silkscreen text and laser engraving is also very nicely done and very edge is chamfered and smoothed. The threads on both ends of the battery tube are bare, with stout rectangular cut threads. Lubed out of the box, they were exceptionally smooth.

For springs, true to the professional-use audience, the driver and tailcap are sporting dual, thick gold-plated springs to prevent damage to the driver and connection breaks under shock loading. The battery tube is removable and is designed with a dual electrical path for the e-switch and mechanical switch to work together.

Like the P17, the tube has a bottom cap with a round opening for the driver spring, with an electrically isolated anodized inner section to direct the electrons to the right spot. There’s o-rings sealing every joint as well, and even with external charging, Acebeam gives the P18 an IP68 rating.

Acebeam, like other higher-end manufacturers, has a very comprehensive warranty. From Acebeam: If the customer experiences any problems caused by manufacturing defects in normal use with an Acebeam product within 15 days of purchase, the dealer will replace that product. 2. If an Acebeam flashlight fails during normal use and any problem covered under warranty occurs within a period of 5 YEARS (60 months) of purchase, the dealer is responsible for warranty service. 3. Acebeam flashlights enjoy a limited lifetime warranty – after 60 months the dealer will attempt to repair the flashlight for the cost of spare parts and shipping (i.e. no charge for labor).

LED, Lens, Bezel, Beam, and Reflector

While most tactical-use lights (save a few) use single LEDs, the P18 features quad LEDs. Acebeam installed the Luminus SFT-40-W. It’s featured in several tactical-use lights I’ve reviewed like the Cyansky K3, Fenix PD35 V3, PD32, and even Acebeam’s P15 Defender. Needless to say, it has pretty much relegated the SST40 to the oldies section of the LED continuum since it’s superior in pretty much every way (besides tint though…the SST40 can still be had in 5000K).

This is a domeless 5050 size LED, and it’s still using the bond wire design (non CSP), but there’s a 4, one for each corner of the die. LES is homogenous and provides even light distribution for high luminance. The SFT-40-W is known for high intensity and excellent throw rivaling the Osram Boost HX with higher output. No CCT is specified, but it’s going to be cool white, generally around 6000K.

The Opple Lightmaster Pro has the tint coming in around 6239K and CRI Ra 65.8, typical and expected here. The duv is 0.0055.

The bezel is an aggressively crenulated PVD-coated blackened stainless unit. It looks freaking awesome with the black-on-black color theme. It extends about 5 mm over the lens at the highest point, so the lens is well protected.

Unlike the P17, the P18 doesn’t have ceramic breaking tips. The lens is a hardened mineral glass unit with a light, blue AR coating. It covers the quad SMO reflector array with 4 somewhat deep reflectors. Each LED is perfectly centered in each reflector with a white centering gasket. The beam has a nicely defined hotspot that’s pretty tight up close, widening out into a perfect circle after about 3 meters. The hotspot transitions to bright spill. The beam does have artifacts typical of multi reflector setups, but it’s not bad, and most users won’t care about that (or the cool white, low CRI tint).

Dimensions and its competition


Body diameter291.14
Head diameter501.9

Dimensions are rounded to the nearest millimeter, and to the nearest tenth of an Inch.


With included battery2609.1
Without battery1876.6

Weight is rounded to the nearest gram, and to the nearest tenth of an Oz.

Flashlight size comparison with its competition

I compared the P18 to some other great tactical flashlights and some similar lights. I don’t have any other multi-LED (pocketable) lights to compare to. The head is about the same size as an Astrolux EC03 triple

Group 1 left to right: Fenix TK16 v2, Acebeam P17 Defender, Fenix PD36 TAC, Acebeam P18 Defender, Fenix TK20R v2

Group 2 left to right: Cyansky K3, Thorfire C8, Acebeam P18 Defender, Acebeam L19 v2

Group 3 left to right: Acebeam P15 Defender, Acebeam P18 Defender, Acebeam P17 Defender.

Acebeam P18 UI: User Interface and Driver

The driver is almost certainly going to be a high-performance buck driver. Acebeam produces some fantastic electronics, and these are constant-output drivers with great, laminar output for continuous output that doesn’t track with the battery voltage sag. This is a very important feature for lights going into the field for pro use. 

The UI is carried forward from the P17 Defender, so if you want the full write up for it, check out that review. The short version is the UI consists of 3 mode groups: Daily, Tactical Mode 1, and Tactical Mode 2.The groups switch up the modes a bit, with Tactical 2 being the sparse one with only 3 modes. Daily and Tactical 1 have 5. Switching between the three modes is pretty straightforward: From off, click and hold the Function switch for three seconds. While holding down the Function switch, press the Tactical switch to enter the mode selection function (the light will ‘breathe’). Click the Function switch again. Strobe means Tactical Mode 1, High mode is Tactical Mode 2, and SOS is Daily Mode. Click the Tactical switch to set the mode. 

Available Modes:

Daily Mode: Ultra Low, Low, Medium, High, Turbo

Tactical Mode 1: Turbo, High, Medium, Low, Strobe

Tactical Mode 2: High, Low, Ultra Low

From OFF:

  • Tap Tactical switch: Momentary on in last memorized mode for Daily Mode or Tactical Mode 1 
  • Fully click Tactical switch: Turns on in last memorized mode
  • Tap Function switch:
    • Daily Mode: Momentary Ultra Low mode
    • Tactical Mode 1: Strobe
    • Tactical Mode 2: Momentary High Mode
  • Press and hold Function switch:
    • Daily Mode: Locks in Ultra Low Mode after pressing for three seconds
    • Tactical Mode 1: Locks in Strobe after one second
    • Tactical mode 2: High Mode
  • Click the Function switch again to return to ON and mode switching in Daily Mode and Tactical Mode 1. Turns off in Tactical Mode 2. 

From ON (Daily Mode):

  • Single click Function switch: Switches modes L-M-H-T-L
  • Press and hold Function switch for more than one second: Locks in SOS
  • Single click Tactical switch: Turns off

From ON (Tactical Mode 1):

  • Single click Function switch: Switches modes L-M-H-T-L
  • Press and hold Function switch more than one second: Locks in Strobe
  • Single click Tactical switch: Turns off

From ON (Tactical Mode 2):

  • Single click Function switch: Switches modes H-L-Ultra Low
  • Single click Tactical switch: Turns off

Mode memory:

  •  Yes, last mode memory in Daily or Tactical Mode 1. None on Tactical Mode 2. 

Low voltage warning:

  •  The battery has a protection circuit and the light features visual LVP to warn of impending shut down


  •   SOS and variable Strobe in Daily and Tactical Mode 1. None in Tactical Mode 2

Lock-out mode: 

  •  None. Unscrew the tailcap ⅛ turn to lock out


  • None


  •  None, but Ultra Low is visible with my cell phone camera

Additional info: Again, since this is the same UI as the P17, my thoughts on it haven’t changed. It’s a bit busy, but fairly straightforward. It includes direct access to Turbo/High mode. I like the nice assortment of modes here, and it makes for a versatile flashlight. I think Tactical 1 Mode is a bit unnecessary and superfluous though, since it’s basically just like Daily Mode with Strobe swapped for Ultra Low. Personally, it would be better to add Strobe to Daily Mode and call it good. I do have one critique, and that’s there is no direct access to Strobe in Tactical 2 Mode and I think that is really important, since it’s the closest to a true tactical mode. Although Acebeam does give you direct access to High mode in the Tactical 2 mode group, and it’s pretty bright, it’s still not the retina-melting Turbo I’d like to see. Strobe mode can be an important self-defense option when a sidearm or other weapon cannot be quickly presented to disorient the assailant or suspect to give the operator time to evade or find cover. LVP isn’t mentioned in the manual anywhere, but the battery has a protection circuit that should pull the plug when the voltage gets to around 2.5 volts.

Acebeam P18 Charging and batteries

The P18 takes a 21700 battery and it came with Acebeam’s IMR21700NP-510A. This is a button top 5100 mAh 18.5 Wh high discharge 21700 battery. This battery isn’t proprietary, and the P18 happily digested every 21700 I stuck in the tube: flat top, and button top, protected and unprotected. The flat top Samsung 50S flat top did rattle around in the tube though. The included battery includes a protection board for extra over and under discharge protection.

Unlike the P17, the P18 incorporates onboard charging via USB type C.

The charge port is protected by an integrated collar that unscrews to expose the port and an LED indicator. It’s red for charging and green for charged. Acebeam claims a 2 A charge current and on a PD power bank and QC charger, my Ruideng AT35 tester shows 1.92 amps. The charge termination voltage was right around 4.16 volts.

I did notice that once the charge termination indicator turned green, the battery was still consuming about 350 mA of current, so I let it sit overnight (8 hours), and the charge termination voltage hadn’t changed. While this is good for the battery’s longevity, you are losing a small amount of runtime. It’s worth mentioning (again), the included charge cable is so short it’s pretty useless, and only good for using with power banks.

Performance test

Lumen measurements

Lumens are measured in my 50 cm integrating sphere with a Digi-Sense 20250-00 data logging luxmeter. The sphere has been calibrated with a Convoy S2+ measured to 260 Lumens and the figures are within 10% of actual. I used the included IMR21700NP-510A 5100 mAh 21700 and tested Medium, High, and Turbo modes. No amps this time due to the wonky current path.

ModeSpecs@turn on@30 sec@10 minutes
Ultra Low12.4 lm2.4 lm
Low10084 lm84 lm
Medium580467 lm467 lm455 lm
High22001771 lm1759 lm1648 lm
Turbo50004367 lm4145 lm1033 lm

he output is coming in a bit low, but within my 10% window for actual output, so once again, I’d trust Acebeam’s output figures here. Note that the P18 is performing about the same as the P17 in these runtimes, albeit with higher sustained output for the Turbo mode. 

Parasitic drain:

  • 1.66 mA

Battery Life: Runtime graphs

Runtimes are measured in my 50 cm integrating sphere with a Digi-Sense 20250-00 data logging luxmeter. The sphere has been calibrated with a Convoy S2+ measured to 260 Lumens and the figures are within 10% of actual. I used the included fully charged IMR21700NP-510A 5100 mAh 21700 and tested Medium, High, and Turbo modes.

ModeSpecified runtimeMeasured runtime (ANSI)Time till shut off
Medium5h 50m6h 11m6h 11m
High2h 56m1h 53m4h 22m
Turbo*2h 55m1h 52m4h 43m

Nothing special to report for the runtime results, other than it’s what I’ve come to expect from Acebeam products, with fully regulated output throughout the runtimes thanks to the buck driver onboard and manageable temperatures. The regulation is great, and there is thermal regulation as well.

Turbo is probably thermally regulated, since the step down to 1000 Lumens happened around 55 C and 2 minutes in. The light didn’t heat up as quickly as the P17 did, reaching 48 C by 30 seconds, and the thermal ceiling of 55 C by 120 seconds in. The light never crested 55 C, and was hand holdable the entire runtime.

High mode also had a step down, but I think this one is timed since the light never hit the 55 C limit. 120 seconds in saw only 38 C. Medium never went over 35 C and maintained 450 Lumens over 5 hours. Towards the end of the rest, there is visual LVP, with a series of timed blinks before the output drops very low and the light shuts off. The user has plenty of warning to change/charge the battery. These are important metrics for professional-use lights, so everything is copasetic in that respect. This is overall excellent performance from a single cell, multi LED light. Even the Sofirn SP36 Pro didn’t do as good, and that one has three 18650s. Of interest here is that the ANSI runtime for Turbo is the same for the P17 and P18.

ANSI FL1 standards: The runtime is measured until the light drops to 10% of its initial output (30 seconds after turning on). This does not mean that the flashlight is not usable anymore. The last column shows how long the light actually works till it shuts off. If there is a + symbol, it means that the test was stopped at that particular point, but the light was actually still running. This happens on certain occasions, with certain drivers, firmware, or batteries.

Peak beam intensity and beam distance measurements

Beam distances are measured using a Uni-T UT383S luxmeter measured indoors at 5 meters using the included fully charged  IMR21700NP-510A 5100 mAh 21700. Measurements taken at 30 seconds.

ModeSpecsCandela measured MetersYards
Ultra LowN/AN/AN/A
Low2862 cd15007785
Medium11,449 cd9000190207
High38,025 cd36,975 cd385420
Turbo98,910 cd85,550 cd (92,025 at start)585 (606.7 at start)640 (663 at start)

No reading at 5 meters for Ultra Low, and I’m coming in low on the figures compared to Acebeam’s numbers, but still very close. The Turbo figure is really impressive, and about what I get from the Cyansky K3 V2, but with three times the Lumens. 

Peak beam info: Peak beam distance according to ANSI FL1 standards: The calculated value of distance in meters at which the flashlight produces a light intensity of 0.25 lux. (0.25 lux is about the brightness of a full moon shining on an object). Columns Meters and Yards show rounded numbers.


I compared the P17 Defender to some other tactical flashlights. Photos taken with my Samsung Note 8. The 40 meter shots with the camera set to 0.3s ISO 200 and 5000K WB. I threw in the Acebeam P17 and some other quad and triple reflector lights to show the difference. I also included the Cyansky K3 V2 since it has comparable throw.

Beamshots of the following flashlights compared:

  • Fenix TK20R V2
  • Fenix TK16 V2
  • Olight Warrior 3S Copper edition
  • Cyansky K3 V2
  • Acebeam P17 Defender
  • Acebeam P18 Defender
  • Sofirn SP36 Pro (quad SST40)
  • Astrolux EC03 (triple SST40)

Disclaimer: This flashlight was sent to me for review at no cost by Acebeam. I have not been paid to review, nor have I been holding back on problems or defects.

Final Verdict


  1. Fantastic quality, fit and finish
  2. Great beam distance
  3. Onboard USB type C charging
  4. Dual-switch UI
  5. Uses standard 21700s
  6. Constant current driver with good sustained output


  1. UI could use some revision
  2. Still no holster or lanyard?
  3. Included USB cable is too short

Explanation on star ratings:

1: Avoid: a match would be a better choice – 2: Poor: significant defect or issues; almost unusable – 3: Average: some defects or issues; but still usable 4: Good: recommended (minor issues) – 5: Great: highly recommended

Reviewer Nick
Author: Nick

4.5 stars: ★★★★⋆

Once again, Acebeam has set the bar pretty high. Not only that, but they aimed for a somewhat tricky corner of the flashlight market with the P18 Defender. Not only did they release a multi LED light, but gave it a tactical modus operandi.

Generally, those are two terms I haven’t had positive experiences with, but in the P18’s case, that was most definitely not my experience. All the typical Acebeam-y things are present: Professional-level performance and features, amazing build quality, fit, and finish, and excellent electronics. I really appreciate the 2 A onboard charging with the retractable charge port cover as well. It more or less meets the factory output specs, it’s somewhat compact, and has great beam distance. Acebeam didn’t burden the end-user with a proprietary battery either, and while most won’t care, it’s a great feature that adds utility since dead batteries can be swapped on the fly.

Although the missing lanyard is a bummer, the missing holster is a downright shame since the P18 is a bit chunky for pocket carry. I’m still disenfranchised over the dinky USB cable, but I can excuse that since it’s better than nothing. At the end of the day though, we need to answer the nagging question: Is this a true tactical-use light? On paper it is, and in real-world testing it would make a decent duty light, and could probably find its way onto a MOLLE kit or web gear for tac use.

On the other hand, it makes a great general purpose light as well, so you could argue it’s a great multi-role light, sort of like the aircraft equivalent of the F-15 or Eurorfighter. I give Acebeam kudos for making the P18 Defender. It’s more or less proven a multi-LED light can be ‘tactical’ and it holds its own in a market dominated by single LED lights, even against its sibling P17.

4.5 stars for the P18 Defender.

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