AceBeam H40 headlamp review

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REVIEW – Headlamps, or flashlights that are worn on the head, are invaluable when working or traveling in dimly lit areas. They may be judged on their brightness, battery life, beam spread, robustness, size, and weight. The H40 by Acebeam combines several features to make it a useful gadget. Read on to see what I think!

What is it?

The Acebeam H40 is a small lightweight headlamp that features a bright LED. The brightness can be fine tuned between 20 and 230 lumens. The light also features a low-power mode of 5 lumens, a turbo mode of 1050 lumens, and an SOS signaling mode at 1050 lumens. All of these brightness and control options are made using a single rubberized button. The Housing is made of aircraft aluminum and is IP68 rated. The housing opens to allow replacement of the single AA battery.

What’s in the box?

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Spare O ring
User Manual
Warranty card

Design and features


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The specifications chart is a little confusing and would benefit from an additional column of the color rendering index (CRI). The CREE-HD XP-L HD has a color rendering index (CRI) between 70 and 80, while the SST-20 CRI 95+ has a CRI of 95 or greater. This means that colors appear to be more natural under the SST LED than under the CREE LED. While the SST LED has better color reproduction, it is not as bright as CREE LED. People who work all day under a headlamp would benefit from the SST LED. The light of the lamp is focused into about a 70 degree arc, based on the relationship between candela and lumens.


The headlamp is packaged in a foam-lined matte cardboard telescopic box designed for retail display.
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The front of the box shows the projector in perspective and some of the performance characteristics. The sides of the box identify the unit serial number, UPC code, QR codes for the website and Facebook page, and applications: Mountaineering, cycling, camping, first aid, construction, and adventure.

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The back of the unit includes the specifications displayed above, description, features, the address of the manufacturer and some compliance codes.

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The inside of the box has everything nicely packaged. The unit also contains a silica gel packet.

Design and features


The design of the AceBeam H40 is tactically inspired. Batman would be proud to wear this on his head. The design features each serve a function. The knurled grip on the battery cover, the cooling fins on the back of the headlamp, the grooves into which the headband fit, the easy to feel operating button are all designed for functionality.

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The design is also backed by a five-year warranty, which attests to the confidence the manufacturer has in its design and construction. As an added bonus, and to make warranty claims easier, the serial number is etched and painted onto the glass lens retainer. There are two improvements I would love to see: adding knurling on the end opposite the battery cover so that it is easier to position the lamp up and down in the headband, and adding a retaining lock on the battery cover so that the cover is not accidentally opened when re-positioning the lamp in the headband.

The reflector does a great job in dispersing the light. The picture below is of the lamp in the lowest power mode.

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The headband has two adjustments; one for the circumference and one for across the top of the head. The circumference fits 26″ unstretched, so will fit hard hats and bike helmets.

The inside of the headband is coated in two zig-zag beads of silicone to provide exceptional traction even on slick or sweaty surfaces.

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The outside of the headband features 3M reflective paint to enhance the visibility of the wearer at night.

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The operation of the lamp is intricate because all of the functions are accessed by one button but the commands are easy to learn and are intuitive after a short while. The lamp is operated by the sequences below:

Single click – turns the lamp on at the previously set intensity.
Double click – toggles the lamp from high intensity (350 lumens) to turbo intensity (1050 lumens). This mode can be reset by a long press when on or by turning the lamp off and then back on.
triple click – starts the SOS Morse code mode (use single click or double click to exit)

long press when off
1 second – turn on ultra-low mode
3 seconds – toggles button lock mode (acknowledged with three blinks of the light)

long press when on
adjusts the intensity from 20 to 230 lumens.

You can see what the lamp looks like as I’m wearing it in the pictures below. Alas, a headlamp will never be the most glamorous accessory.

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The following video shows the view at a local town park on a moonless night in a slight rain. It’s about the worst-case conditions to test the performance of the lamp.

The video is barely able to detect what the naked eye could see, but there was some of the green painted swing set visible at night, lit up by the lamp. Plugging my location into I determined that what I saw is actually very close to the stated beam distance of 106 m (0.106 km).

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It is difficult to test the other parameters of the lamp. Fortunately, AceBeam is a member of The Portable Lights American Trade Organization (PLATO), which allows member companies to publish verified specifications and performance ratings of their products. Because AceBeam is a member of PLATO, comparing the lamp parameters with other PLATO member products is straightforward and reliable.

What I like

  • lightweight
  • bright
  • secure fitting

What needs to be improved

  • unintentional loosening of the battery cover
  • the grip on barrel opposite battery cover

Final thoughts

The AceBeam headlamp will effectively and reliably cut through the darkness and still leave two hands-free. I give it two (flashlight-free) thumbs up.

Price: $34.90
Where to buy: Acebeam and Amazon
Source: The sample for this review was provided by Acebeam.

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