Review: Fenix HM50R (1x1634/CR123A right-angle/headlamp, 500lm, USB charging)

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Review: Fenix HM50R (1x1634/CR123A right-angle/headlamp, 500lm, USB charging)

This Fenix HM50R was provided by Fenix for review.

Extra images can be found in the album:

This review originally appeared on reddit and was converted using Pandoc. Apologies for any formatting issues.

Quick Review

The HM50R is a new 16340/CR123A-powered right-angle light from Fenix with MicroUSB charging. It’s the only small (under 100g with battery and headband) headlamp on the market with onboard charging for a standard, removable battery as of this writing. It can even run on USB power in medium mode without a battery or during charging. That alone would get it a positive recommendation but for one dubious feature: its large timed rampdowns. Despite having a boost driver and thermal sensor, the HM50R reduces its maximum output to around 25% on a timer. Lower modes, too reduce over time, with only the minimum mode having stable output. I see this light as a missed opportunity for Fenix and would love to see a version 2.

I’m likely not the intended market. I can usually manage to put myself in the mindset of someone who uses tools diffrently from me, but I’m struggling with this one. My best guess is that Fenix is trying to compete with the likes of Black Diamond and Petzl, who advertise headlamps with extremely misleading runtimes that start out high, plummet, then run at a tiny fraction of their original output for hours or days. Fenix isn’t doing anything misleading: they put a graph right on the box showing what the light will do, and it does exactly that. Maybe this is a benefit to a user who’s absentminded and has a habit of selecting too high an output and not thinking about battery life.

I asked my Fenix rep about this and was told that the rampdowns are intended to work with how human vision adapts to lower light levels to extend battery life without significantly hurting visibility. I could appreciate a feature like this if it was a bit less aggressive and there was a way to disable it. I definitely found myself noticing my ability to see dropping while walking at night wearing the HM50R and had to reset the brightness to maintain my ability to see as well as I wanted. It certainly extends battery life though, with the highest mode running for 2.5 hours if not reset.

The HM50R squanders other potential advantages as well. The user interface uses an e-switch, but has no shortcuts. Press-and-hold from off triggers the last-used mode. There’s no way to get to high, low or anything else from off. Most premium lights with electronic switches have shortcuts from off to at least low, high and last-used if not a medium mode as well. Fenix advertises that the HM50R is good as a headlamp or a handheld flashlight, but fails to include a pocket clip like most of its competition.

The beam itself is cool white, with a noticeably purple spill. Fenix makes several neutral white products and extols its virtues for color accuracy and user comfort, but does not use it on the HM50R. I don’t have a spectrometer and can’t measure CRI, but my eyes tell me it’s very average on the HM50R. It does wash out subtle variations in color and I do find the light it produces a bit fatiguing in long-term use.

To its credit, the HM50R does everything it says it does. Output and throw numbers even came in above spec. It’s a sad thing that performing as advertised needs to be a noteworthy positive trait of a premium product, but that’s the headlamp market. The built quality is excellent. The waterproofing is good despite the USB port. Low overall weight and some silicone added to the inside of the headband make the HM50R both stable and comfortable on my head.

  • + Does what it says on the tin colorful plastic retail packaging
  • + The only USB charging small headlamp on the market that uses a standard, removable battery
  • + Effective boost driver capable of full output on a low battery or in cold weather
  • + Great build quality and waterproofing, as usual from Fenix
  • + No blinky modes
  • + Makes 35 lumens on USB power while charging or without a battery
  • + Fast charging
  • - Intentionally doesn’t maintain its output, squandering the advantage of its boost driver
  • - No pocket clip
  • - Cool white, low-CRI; washes out colors
  • - No shortcuts, and long-press required for on/off

The HM50R seems like a good choice for a spare headlamp to be given to people too inexperienced or absentminded to manage their battery power effectively, but I’d like it a whole lot more if I could turn the rampdown feature off.

Details and technical analysis


The HM50R is packaged with:

  • A Fenix protected 16340 battery
  • A USB cable
  • A headband with silicone holder
  • A spare silicone holder
  • A spare USB port cover
  • Spare o-rings
  • A manual

There is no pocket clip, a significant omission.

Modes and user interface

State Action Result
Off Short-press Battery check
Off Long-press Memory
On Long-press off
On Short-press Next mode (L->H)

Operation is simple to understand, but not exactly convenient. Most lights at this price point have shortcuts to low, high and either medium or last-used. They are missed here.

Output and runtime

All runtimes are with the included Fenix 700mAh 16340 battery. Calculated runtimes are based on current with a full battery and do not account for the light’s rampdowns. There is a thermal stepdown claimed to trigger at 65C, however it was never reached even when continually resetting the timed rampdown without cooling.

I also did a test on turbo manually resetting the brightness.

Mode Advertised Lumens Estimated Lumens FL1 throw Graph Advertised Runtime Time to 80% Time to 50% Time to 10% Tailcap current
Standby lumens - - - - - - 2 years 37.2 microamps
Low 4 3 - - 90 hours - - 102 hours (calculated) 6.86mA
Med 30 35 21 - 24 hours - - 12 hours (calculated) 56.7mA
High 130 141 43 graph 10 hours 29 min 72 min 9.4 hours 245.8
Turbo 500 547 86 graph 2.5 hours 5 min 10 min 145 min ~1.5A
Turbo reset 500 547 86 graph - 28 min 28 min 36 min ~1.5A


As a headlamp, the HM50R is very comfortable. I’m used to much larger 18650-powered headlamps, and this much smaller light is hard to even notice on my head. The headband has a strip of silicone which helps keep it in position. I thought this might feel sticky and uncomfortable, but didn’t really notice it in practice.

As a handheld, the HM50R is tiny and hard to minipulate. It’s impossible to grip in a fist without obscuring part of the beam. I ended up mostly using a pinch grip on the head. The ergonomics work well as a headlamp first and handheld second, but many people use right-angle lights the other way around; I don’t think this size is ideal for those users. The lack of a pocket clip seems to suggest Fenix agrees. There are some hard angles, and I don’t like carrying the HM50R in a standard pants pocket without a clip, but I did find I could stick it and its headband in a cargo pocket, which might be good for someone who wants to carry a headlamp for occasional use.

Battery and charging

The included battery is a Fenix branded, protected 16340. Charging via MicroUSB is very fast, finishing in an hour with a fully discharged battery. I measured 713mA charging current. Capacity is advertised at 700 mAh and tests slightly higher on my Opus BT-C3100. There is mechanical reverse-polarity protection, so most flat-tops probably won’t work. A CR123 primary can also be used.

16340 is certainly a popular enough size, though the marginally larger 18350 has recently gained a much larger capacity option in the Aspire 1100 mAh (originally sold as 1300 mAh) cell. This is a 50% increase in capacity for a trivial increase in volume. I doubt this cell was available during the design of the HM50R and previous 18350 offerings weren’t really compelling, so it’s hard to fault Fenix for not supporting them, but I really think this light needs a version 2 and would urge Fenix to consider a slightly larger battery tube. The head is already big enough that it wouldn’t increase the maximum dimensions of the light at all.

Build quality

As usual for Fenix, the build quality is excellent. There are no tool marks, finish defects, uneven machining or other problems. Unusually, the threads were unlubricated; I asked about this and was told it’s meant to be that way and does not require lubrication. I think this is due to the recommended procedure for installing the lamp in the headband; the tailcap and battery should be removed before pushing the lamp through the holder. The holder is silicone, and the usual silicone-based grease would damage it, not to mention being messy.

The lack of lubrication may slightly impact waterproofing. During testing, I found a drop of water made it past the o-ring into the threads, but did not enter the battery compartment. No water entered the USB cover, and overall, I think the HM50R’s waterproofing is fine for the intended use and advertised IP68 rating.

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 HM50R’s bezel unscrews easily and the reflector comes out with it. There’s nothing in the way of the emitter, though the MCPCB is a bit of an odd shape, sitting on a floating shelf. As there are no XM pattern emitters I’m especially fond of, a bit of time with a file on a 16mm XP MCPCB made it fit. The emitter I chose is a 5000K, 80 CRI Nichia 219C, one of my favorite emitters of all time. There’s marginally less output, marginally more throw and slight changes to power consumption, but none of that is the point.

The point, of course is that the light coming out of the headlamp is pleasant to use now. It looks like sunlight at midday, makes colors appear natural and vivid and doesn’t produce fatigue. Fenix should consider using this emitter in its products.

Mode Estimated Lumens FL1 throw Graph Time to 80% Time to 50% Time to 10% Tailcap current
Low 3 - - - - 2 years 6.81mA
Med 34 23 - - - 12 hours 56.78mA
High 132 48 - - - 3 hours 250.5mA
Turbo 480 92 graph 4 min 10 min 2.5 hours ~1.4A

Ceilingbounce – flashlight testing and runtime graphs for Android | Zak Reviews – my flashlight reviews, with lots of runtime graphs

Edited by: sb56637 on 09/02/2017 - 12:03
Last seen: 2 weeks 1 day ago
Joined: 12/13/2015 - 10:37
Posts: 1061
Location: Canada

Great review!

The intentional step down on medium and high is such a deal breaker!

I have an HL50 modded with single E21a and absolutely love it.