Acebeam UC20 Review – User Serviceable EDC Flatlight!

1. Pricing & Availability
2. What comes in the box?
3. Design & Construction
4. Size & Measurements
5. User Interface
6. Emitter & Beam
7. Mode Chart
8. Runtime
9. Driver & Regulation
10. Batteries & Charging
11. Switch
12. Carry & Ergonomics
13. Competition
14. Conclusion

Pricing & Availability

Acebeam sent me this light in exchange for an honest review. Here is the official product page where you can see current pricing. At the time of writing it’s $60 USD.

What comes in the box?

UC20 comes in a small cardstock retail box. Inside is:

• The light itself
• User manual, warranty, and certification papers
• Short USB A-to-C charging cable
• Spare port cover

Design & Construction

UC20’s design is in line with most other EDC flat-lights on the market. It’s a slab with rounded corners and a somewhat unique tapered head. I’m not sure what the cutouts on the sides are for.

The CE and don’t trash labels are very nicely hidden under the pocket clip. That makes it extra strange that Acebeam put a big ugly “don’t shine this in your eyes” warning, QR code, and serial number in plain sight. These detract from the sleek look of the light.

Build quality is great. The machining and finishing are excellent. The switches feel good and all the parts line up perfectly.

Construction: The whole light is screwed together and nothing is glued. It will likely void the warranty, but you can take the whole light apart to repair it, swap the LED(s), or replace the battery if needed. No other light in this class lets you do that.

Size & Measurements

Olight Warrior 3S | Surefire G2X Pro | Acebeam UC20 | Skilhunt MiX-7 Gen 2 Plus | Mini Maglite

Measurement	Measured (mm)
Width (not including port cover)	25.0
Thickness (not including clip)	15.0
Length	132.0
Side Switch Diameter	9.7
Tail Switch Width	14.5
Tail Switch Height	9.5
LED Footprint	3535
Weight (g)	83

User Interface

This is a solid UI. It’s largely in line with the typical e-switch UI I prefer, plus it has an awesome Turbo/Strobe switch on the tail!

Basic E-switch UI Checklist: 9/12

• 1C on/off✅
• 1H to change brightness✅
• Stepped levels✅
• Main rotation is Low-Med-High✅
• Ultralow shortcut: 1H from off✅
  • Ultralow mode is 5lm on this light, which may be too bright for some. 1lm is the industry standard Moonlight/Ultralow mode and would have been better.
• Low shortcut: 1H from Ultralow✅
• Turbo shortcut: 2C from anywhere❌
  • 2C activates red. You must half-press the tailswitch for Turbo.
• Strobe shortcut: 3C from anywhere❌
  • 3C activates UV. You must full-press the tailswitch for Strobe.
• Mode memory for Low, Medium, and High✅
• No mode memory for Moonlight, Turbo, and Strobe✅
• 4C to lock/unlock❌
  • Lockout is entered and left by a very long hold. That’s too easy to be done by accident in a pocket or bag, especially since there’s no mechanical lockout option here.
• Does something when you click the switch in Lockout mode✅

Notes:

• Accessing red or UV modes will turn on the white light first and then switch to red or UV. That’s bad if you’re wanting to use red to preserve night vision. Acebeam should add a slight delay between the first click and the light turning on, so if you click again for read mode it goes directly to red.
• It’s great that red and UV have shortcuts from off, but I wish they hadn’t replaced the typical Turbo and Strobe shortcuts. I frequently try to access turbo using the side switch and end up with dim red instead. I don’t want to have to move the light around in my hand just to access Turbo for a moment. 2H for red and 3H for UV would have been better, and would allow the typical 2C Turbo and 3C strobe shortcuts to remain.
• I’m delighted there are only 3 modes on the main rotation. Acebeam lights usually have four and I find that’s too many.
• I love when lights have a dedicated Turbo switch, and this one works ok, but it could use improvement. Holding for <5 seconds activates Turbo/Strobe momentarily. If you hold for more than 5 seconds, it will stay on after you release. That’s a weird setup and it’s not very intuitive. A short press and release (<~250ms) should be constant-on, and a long press (>~250ms) should be momentary on until you release the switch. That’s how most other manufacturers handle it and that works better.

Emitter & Beam

The main white LED is a Luminus SFT25R in 6500K, and it’s the perfect choice. It’s bright and intense, so it can generate respectable throw/candela from UC20’s small reflector. There are also red and UV secondary LEDs under two diffusers/optics.

Accessing the LEDs for an emitter swap is super easy. Just undo two screws on the head and the whole bezel assembly comes right off.

The main beam has a crisp and relatively narrow hotspot compared to most other EDC flat-lights. That’s a nice surprise because I usually find them too floody. The spill is relatively narrow but gets the job done. I really like this beam.

In the beamshots below, camera settings are fixed and the wall is 2.8M away.

In the beamshots below, camera settings are fixed, the basketball goal to the right of the hotspot is 39M away, and the power pole in the center is 185M away.

The red and UV “beams” aren’t focused, and because of where they sit on the head they shine sideways and are lopsided. The red isn’t great but it works well enough. The UV is pretty bad because it’s unfocused and has a ton of visible purple light. Here’s a comparison between this light’s UV and a Skihunt MiX-7 Gen 2 Plus with a proper reflector and ZWB2 filter.

Mode Chart

Disclaimer: All of my measurements are taken at turn-on. Lumen measurements were taken on a Texas Ace 3.5″ Lumen Tube. A candela measurement was taken at 10 meters with an Opple Light Master III on the highest brightness, and other candela figures were calculated relative to that. CRI, CCT, & DUV data were taken for each mode from a few feet away at the center of the hotspot with the Opple Light Master and Waveform DUV Calculator. Runtime tests were performed with the Ceilingbounce app on my smartphone. These tests were performed with a fully charged included battery unless otherwise specified. I cannot measure moonlight directly, so moonlight readings are calculated based on the brightness relative to the next-lowest mode. None of this is professional equipment, so take these measurements with a grain of salt.

The official specs are above, followed by my own measurements below.

Level	Lumens	Candela	Throw (Meters)	CRI (Ra)	Color Temp. (K)	DUV (Tint)
Turbo	960	15000	250	69	6620	0.0035
High	430	6700	160	68	6370	0.0054
Medium	180	2800	106	66	6100	0.0080
Low	62	970	62	65	6011	0.0097
Moonlight	3	47	14	64	5890	0.0118

Red has two levels, 12lm and 34lm. UV has one level. Take those values with a grain of salt because I’m not sure my lumen tube measures red accurately.

Runtime

Performance is good/average. Turbo brightness, sustained brightness, and runtime are all in line with most other lights in this class like Wurkkos HD01, Olight Arkfeld Pro, and Nitecore EDC25. I appreciate how flat the runtimes are, staying a consistent brightness until the battery is virtually empty.

Thermal regulation: My Turbo and Turbo Cooled tests are virtually identical, so there’s no active thermal regulation here, just timed stepdowns. That means performance will be consistent, but not optimized for ambient temperature.

LVP (Low Voltage Protection) is present and works well. It will shut off when the battery is effectively empty, but it can be temporarily re-activated in an emergency.

Driver & Regulation

The driver isn’t specified. Based on the regulation performance below and Acebeam’s history, I suspect it’s a Buck circuit.

Regulation performance is ok. It maintains most of the Turbo brightness down to ~50% charge, and all the other modes are flat down to 25% charge or less. A little bit better Turbo regulation would be nice but this isn’t bad. It’s certainly leaps ahead of the Olight Arkfeld series and Wurkkos HD01.

UV regulation: The UV LED stays a consistent brightness down to ~25% and then won’t work below that, so I think it may have its own boost circuit just for that LED. Normally UV LEDs are very poorly regulated unless they’re on a boost circuit.

PWM: There’s no flickering on any white or red mode, according to my Opple. I didn’t PWM test UV.

Parasitic Drain: I can’t reasonably measure parasitic drain on this model because of the connector.

Batteries & Charging

The battery is a built-in 1000mAh pouch cell. Unlike all other lights in this class, you can replace it when it eventually wears out! Doing so will probably void the warranty, but the warranty should expire long before the battery needs replacement (it’s 24 months on the battery, according to the included warranty card).

Charging is facilitated by a USB-C port on the side. It’s covered by a silicone port cover, and a spare is included. It cannot be used while charging. There’s no powerbank function, which makes sense considering the small battery.

The battery indicator is a glowing ring around the side switch. It glows when the light is plugged in or turned on. Here’s what it means:

State	Color/Pattern	Meaning
Charging	Green	Fully Charged
Charging	Blinking Red	Charging
Unplugged	Green	>30%
Unplugged	Red	10-30%
Unplugged	Blinking Red	<10%

Switch

UC20 has a side switch for most tasks and a tailswitch for Turbo and Strobe. The side switch is momentary electronic and is made of blackened steel. The tailswitch is a two-stage electronic switch made of anodized aluminum. A half-press activates Turbo and a full press activates Strobe. There’s a hard wall between a half press and a full press so you won’t activate Strobe by accident. Well done Acebeam!

Carry & Ergonomics

Ergonomics are good. It’s comfortable in a forward grip when using the side switch, and reverse or cigar grip when using the tailswitch.

The tailcap is not magnetic.

Competition

Here are some lights in the same class and how they compare.

Olight Arkfeld Pro:

• more expensive
• similar brightness, less throw
• green laser instead of red
• excellent ergonomics
• best-in-class rotary selector switch
• no dedicated Turbo/strobe switch
• magnetic tailcap
• proprietary magnetic charging system
• totally non-user-serviceable, even the clip
• better battery indicator
• proper deep carry clip

Jetbeam E26:

• A bit more expensive
• larger battery and more runtime
• rotary channel selector
• Turbo/Strobe tailswitch
• Laser instead of red light
• Larger and more aggressive aesthetic
• similar battery indicator

Nitecore EDC25:

• a bit more expensive
• more brightness and throw?
• dual tail switches, no side switch
• Instant Turbo/Strobe button can do one or the other, not both
• better battery indicator, plus a brightness level indicator
• somewhat user-serviceable, but not as much as UC20
• super light weight for it’s size
• larger and more aggressive aesthetic
• stamped aluminum sandwich construction

This section is not comprehensive. If I didn’t include a particular light here, it doesn’t mean it’s bad or doesn’t deserve to be here. I simply cannot list every possible competitor.

Conclusion

The EDC flatlight market is quickly getting crowded but Acebeam UC20 sets itself apart with a relatively throwy beam, red secondary light, and user-replaceable battery (may void the warranty). The main beam, throw, and switches are great. The pricing, build quality, brightness, runtime, regulation, and clip are all good. The UI is good overall but I have a couple gripes I’d like to see improved. The UV is pretty bad. If you’ve been holding off on an EDC flatlight due to e-waste concerns from built-in batteries or wanting a red secondary LED, this may be the light for you!

Thanks to Acebeam for sending me this light for review!