Wuben TO50R review (21700, 4xLH351D, 5000K CRI90)

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maukka
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Wuben TO50R review (21700, 4xLH351D, 5000K CRI90)

Disclaimer: I received the Wuben TO50R free of charge from hc-lights.fi

TL;DR
The Wuben TO50R is a 21700 flashlight with four high CRI Samsung LH351D LEDs at a neutral white 5000K. It features integrated Micro-USB charging and comes with a protected battery. The USB port can also be used as a powerbank via an included adapter.
Designed by Wuben and our very own the, the TO50R is a very well thought out multi purpose light with one of the design goals being good color rendering for photography. The beam with the stock optics is wide and even with great tint consistency and color.
Even with my small quibbles I rate the Wuben TO50R as one of the best all-rounders for a stock light at the time of writing (10/2019). It sets the bar for driver efficiency while offering an intuitive user interface and high quality neutral light. It’s right up there with my favorites, the BLF/Lumintop FW3A and a 219b modded Zebralight SC64c, but doesn’t get carried as much because of the larger size.

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

Manufacturer’s specifications
Battery: 21700 or 18650 with the included adapter (accepts button and flat tops, protected and unprotected, but not unprotected flat top 18650s, Wuben 21700 4800mAh battery included)
LED: 4x Samsung LH351D 5000K CRI90
Waterproof: IP68, 2 meters for 1 hour
Impact resistance: 1.5 meters
Mode memory: yes (except turbo and blinky modes)
Low voltage protection: yes
Thermal regulation: yes
Lockout: electronic and physical
Tripod socket: no
Tailcap magnet: yes

Manufacturer’s output specs
Maximum output: 2800 lumens (stepdown to 1000 lumens after 1 minute)
Other output levels: 1/10/50/250/1250 lumens
Light intensity: 5329 candela
Beam distance: 146 meters
Special modes: strobe, beacon 1/10s, SOS

Measured dimensions and weight
Length: 124.5 mm
Head width: 31.0 mm
Handle width: 28.0 mm
Weight: 125 g plus 73 g for the 21700 battery or 51 g for an 18650 + the adapter

Box and contents

Bundled in the box with the light:
21700 4800mAh battery (Wuben ABD4800)
18650-21700 battery adapter
Holster
Lanyard
Micro-USB to USB-A male+female charging/powerbank cable
Two spare o-rings
User manual

Physical appearance


The deep carry pocket clip is quite sturdy and very difficult to remove. It will not come off accidentally.


The tail end holds a powerful magnet which is easily able to hold the light’s weight in any orientation.


The four Samsung LH351D 5000K CRI90 emitters are behind a user serviceable bezel (not glued) and optics.


The optics are from a Chinese manufacturer Kingbrite. The model number is KB-P25-4-XP, which is also available in several different beam angles for different applications. The stock optic is specced at 15°, but as can be seen later from the measurements is much wider with the LH351D. Also seen in the photo are a 10° and a beaded 60° optic.

As far as my googling showed, the Kingbrite optics are only available from the manufacturer on Alibaba. This is quite a shame, since the optic doesn’t have a glass lens for protection in the TO50R. In case of an optic accident, you’ll most likely have to go to the retailer or Wuben for a new one. This hurts serviceability. Carclo would have been a better choice in terms of fixing and moddability. There’s nothing to complain about the Kingbrite’s performance though.


18650s can be used with the included adapter sleeve. Unprotected flat top 18650s are too short and don’t make contact on both ends, but every other type of battery I tried worked, including a flat top 21700 and a button top 18650 with no protection circuit. Just make sure the battery is able to handle >10A.


On my sample the threads were a bit rough on the unanodized end at the head, but there should usually be no reason to open it.

User interface

The light is operated via two electronic side switches, power and mode. There’s a USB charging indicator LED behind the power switch which also lights up blue for 5 seconds when the light is turned on. There’s no way to configure the light to be always on.

There was a clear design choice from the beginning, no difficult double or triple clicks and the light immediately turns on and off when pressing the power switch. Click the light on and then cycle modes with the mode switch. That’s all a normal user would have to remember, but there’s more of course.

From off:
Click power switch to turn on the light on the last mode used (turbo and blinky modes are not memorized)
1 second long press of power switch for lowest output (moon)
8 second long press of power switch for electronic lockout, 5 second long press to unlock
1 second long press of mode switch for momentary turbo
2 second long press of power switch for special modes (strobe, beacon 1/10s, SOS)

From on:
Click power switch to turn off
Click mode switch to cycle modes (low-med1-med2-high-low)
Hold mode switch for momentary turbo, release to return to the previous mode
Hold power switch for permanent turbo, hold again to return, click to turn off

The UI is intuitive with important shortcuts to the lowest and highest modes and memory. No need to teach the UI if you hand the light out to someone. The only thing I’d like is a way to go backwards in modes.

Link to UI graph

Battery measurements

The included 4800 mAh 21700 battery (ABD4800) has a protection circuit to prevent overcharge, over discharge and short circuits (too much current).

The battery is very long and can’t be inserted into most chargers unless they’ve been designer for protected 21700s.

Length: 75.3mm
Width: 21.45mm
Capacity: 4696mAh at 2A down to 2.5V
Energy: 16.8Wh at 2A
Maximum current (OCP): none or above 20A (did not trip after 1 minute @ 20A)
Minimum voltage (LVP): 2.47V
Internal resistance (Ri): 35 mOhm (measured at 10A DC)

Discharge curve at 2 amps.

Integrated charging

The integrated charging uses the Micro-USB connector. It draws a hair under 2 amps from the USB power supply and fills the included battery in about three hours. The indicator LED on the power switch is a steady blue when the charging has completed.

The charging circuit uses a buck driver and is more efficient than a common linear circuit. Charging a 16.8Wh battery consumes 20.6Wh from the power source (82% efficiency after cable and contact losses). A linear circuit wasting the excess voltage from the USB supply would be about 70% efficient.

Battery voltage after integrated charging: 4.17V

Using the TO50R as a powerbank

I discharged the Wuben battery at 2A at first, until the USB voltage dropped to 4.35V after 1h 17min. At this point the total energy output was 12.3Wh. Then I lowered the discharge current to 1A, which ran for 13 minutes more. To extract all the juice from the battery, I finished the test at 0.5A. Clearly the boost driver of the USB output isn’t capable enough to keep the output at 5V at higher currents when the battery voltage drops too low.

Not only is the charging process quite efficient, this is true for the discharge as well. The total energy extracted was 13.83Wh, which translates to about 82% boost driver efficiency given that the battery capacity is 16.8Wh (13.83Wh/16.8Wh=0.82). This is a very good result for something that isn’t the device’s main task and has to be implemented in a tight space. Battery voltage after the USB discharge test was 2.90V.

Size comparison

The TO50R is quite a lot bigger than the most compact 18650 lights popular at the moment. It’s a bit larger than the closest competitor I have for it, the Acebeam EC65, which also uses a 21700 battery with quad emitters.

From left to right: Wuben TO50R, Acebeam EC65, Emisar D4

Beamshot comparison

While the emitters in all of the lights are different, they are very similar in configuration (compact quads). The Wuben TO50R with its LH351D is clearly the floodiest of the bunch while the Acebeam EC65 has the biggest output. With a full battery and cool body, the D4 does put out a formidable amount of light, but it is also the one that suffers the most from thermal throttling and output loss when the battery voltage decreases.

Individual beamshots
TO50R
D4
EC65

Individual beamshots
TO50R
D4
EC65

Beam and tint

The beam of the TO50R can best be described as floody and even, in all sense. The color temperature and tint is consistent all throughout the usable beam and there’s no distracting artifacts even on a white wall. This makes it especially good for its intended purpose, photography.

The LH351D behaves typically with regard to drive current. It gets cooler and less green when it heats up. I.e. when the light gets hot, the CCT increases and duv decreases. On turbo while the values are 4800K/0.0030 initially, it changes to 4840K/0.0010 at 30 seconds and when already heated up it’s at 4870K/0.0000. There’s no time for serious overheating of the LEDs before stepdown so the shift is relatively small.

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

CRI data on turbo measured from the hotspot at 30 seconds

CRI data on mid (119 lumens)

Output and runtimes

Driver efficiency is excellent. At 124 lumens per watt, the 280 lumen mid mode runs for over 7 hours and continues to work for another two at 50 lumens. This results in 2109 lumen-hours on the bundled 16.8 Wh 21700 battery. The TO50R can also sustain a high 1000 lumens.

Rather interestingly, the output gets gradually higher during the first 5 seconds on turbo from 2100 to 2900 lumens. This only happened with the included Wuben battery. On a higher performing Samsung 30T, full output was available right away.

What I’m not very happy about is that the boost driver doesn’t allow turbo on a partly discharged stock battery. Its maximum is 1400 lumens below 3.8V or so. In practical terms this means that you’ll be able to use turbo in 30 second bursts for about 15-20 times. With a low internal resistance battery such as the Samsung 30T, the output will stay higher for longer.

To be fair, the Acebeam EC65 behaves similarly as it only allows maximum turbo output for one time in its stock form using the bundled battery. On the other hand on the EC65 the output drop is less dramatic at first going from 3500 lumens to 3000 lumens. The second drop is from 3000 lumens to 2600 then to 2200 until the battery is empty.

Standby drain
There’s some parasitic drain on the batteries when the light is switched off. This is understandable due to the electronic soft switch. It would take about two years to drain the battery inside the light.

Standby current: 270µA

Low voltage protection
While the light itself has a low voltage cutoff above the one on the battery, the light’s integrated charger can’t reset the battery LVP. So if you manage to discharge the battery low enough either by letting it sit in the light for prolonged periods (~2 years) or using it in a non-LVP light, you’ll have to figure out how to reset it some other way. And since the protected 21700 doesn’t fit any standard charger, this calls for measures not most users are familiar with (bench PSU, connecting the battery briefly in parallel with another lithium ion battery for example).

Flicker
I measure the flicker optically from the LED with a Thorlabs DET36A/M photodetector and an oscilloscope.

Typical for buck/boost drivers, there’s some ripple on the output. It’s not visible on any mode though. Even though the frequency of the ripple is as low as 800 hertz on moon, the modulation depth is very low. The snob index of 0% on all modes guarantees that it will not be an issue.

Moon

Other modes
Micro
Low
Mid
High
Turbo

Temperature
Thanks to high efficiency, the TO50R doesn’t get very hot in normal use.

On the mid mode (280 lm) it only reached about 10°C over ambient (35°C in 24°C ambient).

The light will step down when the body reaches about 55°C. The light will feel very hot to touch at this point. On high and turbo, if left alone without cooling it will hold output steady at 1000 lumens while the surface reaches 65°C at 1.5 hours before the final stepdown. Normally the user will probably lower the output before this ever happens, but I don’t recommend leaving the light alone on high or turbo as this is not good for the battery.

Strobe
Strobe and other special blinky modes are activated with a 2 second press from off. Strobe alternates between 7 and 16 hertz every ~1.5 seconds.

Verdict
The TO50R is quite a lot bigger than the most popular 18650 triples/quads. Although likely not the ideal EDC partner, it’s far from unwieldy and readily disappears into a jacket pocket. The deep carry pocket clip is very sturdily attached, but also difficult to remove if you’d prefer to go without it. A very strong tailcap magnets allows for more creative lighing options.

The biggest advantages of the TO50R are its great light quality from the Samsung LH351D LEDs and the efficient driver powering them. Getting over 2000 lumen hours (i.e. 280 lumens for over 7 hours) of CRI90+ light from a compact flashlight is quite unheard of. It can also provide 1000 lumens continuously for 1h 40min without external cooling, which is not a small feat in its weight class.

As expected for a compact quad with TIR optics, it is clear that the TO50R is aimed for close quarters. The beam is very floody and even, which is great for photography, but falls short when you need some throw. It is possible to switch the optics for a narrower spot version, but the LH351D with its large apparent die size will not shoot far in this arrangement no matter what.

The Chinese stock optics aren’t protected with a glass lens, which could become a problem. The optics are available in different beam angle flavors but only from Alibaba. I hope retailers will stock up on them. The bezel is not glued and the emitters and optics are easily replaced for modding.

The choice of Micro USB instead of USB Type C is a bit strange, since Wuben uses USB-C in some of it other new lights. That wouldn’t really be a problem, but the powerbank USB output is hindered by the fact that you need to carry an extra Micro to USB-A OTG style adapter. At least Wuben included a cable which can be used for both charging the light and utilizing the power bank feature and not one of those small OTG adapters that will surely be lost. For a LiIon to USB boost driver in a flashglight, the powerbank output performs very well at over 80% efficiency.

Even with my small quibbles I rate the Wuben TO50R as one of the best allrounders for a stock light at the time of writing (10/2019). It sets the bar for driver efficiency while offering an intuitive user interface and high quality neutral light. It’s right up there with my favorites with the BLF/Lumintop FW3A and a 219b modded Zebralight SC64c.

+ Good CRI and neutral tint
+ No tint shift within the beam
+ An intuitive and user friendly UI
+ Momentary turbo from off and on
+ Blinky modes are hidden and cannot be accidentally activated
+ Efficient driver
+ No flicker, great for photography
+ Flat regulated output
+ Sustains 1000 lumens continuously without cooling in a compact body
+ Good powerbank efficiency
+ Strong tailcap magnet
+ Deep carry pocket clip which doesn’t come off accidentally
+ Bezel is not glued and optics and emitters are easily replaced
+ MCPCB securely mounted with screws
- Included battery is very long and will probably not fit in most chargers
- Maximum output not available when battery is more than 1/3 discharged
- Pocket clip is difficult to remove
- Bit too large for EDC
- For the powerbank function a Micro USB with an adapter is more cumbersome than USB-C
- No way of backing down in brightness
- Switch backlight cannot be configured to be always on, which makes locating the switches difficult in the dark if you don’t use the pocket clip for orientation
- No glass lens protecting the optics with spare/alternate optics not easily sourced
- The integrated USB charger can’t reset the LVP circuit in the battery

Edited by: maukka on 10/07/2019 - 04:28
Chatika vas Paus
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Thanks for the reviews and measurements.
It looks like they’ve finally changed the position of the mcpcb fixing screws. In your specimen are in the correct position, not like mine from group buy, where Wuben broke two of the four optics legs, making it more susceptible to damage.

maukka
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Yes, the latest version has that problem corrected. Mine also had a good amount of thermal paste evenly spread under the MCPCB, which I heard wasm’t done so well on some earlier models.

Chatika vas Paus
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Where do you get these extra optics from?

maukka
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The ordered them from the manufacturer on Alibaba.

Chatika vas Paus
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There is not even an option to add to the cart. Or I’m blind. I’ve never ordered from there, and I’d like to try something wider with this flashlight.

Btw. This is probably -

maukka wrote:
+ Included battery is very long and will probably not fit in most chargers
maukka
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What, I like my long batteries! Smile

Fixed, thx.

SKV89
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Maukka, thanks for your excellent review. I bought two stock TO50R and one modded by contactcr. I agree with everything you said in your review.

What I am surprised about is that the tint is so much better in the TO50R you tested. I tested the initial batch:

High Mode:
CCT: 4850K
DUV: 0.0050

Turbo Mode:
CCT: 4968K
DUV: 0.0048

Wonder where Wuben bought the new batch of emitters and what tint bin they got.

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Thank you maukka for the great and detailed review!

Chatika vas Paus wrote:
There is not even an option to add to the cart. Or I’m blind.

Alibaba is for retailers/wholesale only. Sorry!

Where do you live? I might be able to ship you one “60-degree” lens.. It’s very floody on the 50R. PM me for details.

=the=

 

contactcr
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Chatika vas Paus wrote:
Thanks for the reviews and measurements. It looks like they’ve finally changed the position of the mcpcb fixing screws. In your specimen are in the correct position, not like mine from group buy, where Wuben broke two of the four optics legs, making it more susceptible to damage.

It also looks like the newest is now sitting right on the substrate. You can see pieces of what I guess is silicone hanging off.

maukka
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contactcr wrote:
It also looks like the newest is now sitting right on the substrate. You can see pieces of what I guess is silicone hanging off.

You’re absolutely right. Part of the silicone substrate had been peeled off from the top of the LED. I couldn’t see it at first with my eyes and can’t be sure if it happened at the factory or after I had tried the alternate optics for several times.

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Looks like you had the same results with higher drain/lower IR batteries as I did. Even when fully charged the stock cell won’t allow me to go to momentary or constant turbo when in high. With a NCR18650GA or 40T everything functions as it should.

A few times the mode order seemed to get… weird when using the stock cell too. But I have an earlier GB model so that could be part of it. Glad to see the efficiency is so great though, this has become my go-to bag/jacket light.

maukka
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You are right. Now that you mention it, I also noticed that the behavior was strange after the battery voltage had dropped so low that the turbo didn’t work. If I recall correctly, when you tried to activate momentary turbo from high, the light didn’t get any brighter but when you released the W switch, it went back to a lower level, not back to high.

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One of the most under-estimated light. I never thought I would like it that much. Reliable, solid, beautiful tint, perfect flood. This light is the perfect tool for inspection jobs. Near 2 hours at 1000 lumens is simply amazing. This light is my best purchase of 2019.

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maukka wrote:
You are right. Now that you mention it, I also noticed that the behavior was strange after the battery voltage had dropped so low that the turbo didn’t work. If I recall correctly, when you tried to activate momentary turbo from high, the light didn’t get any brighter but when you released the W switch, it went back to a lower level, not back to high.

Exactly what happens on mine with drained cells (earlier or later depending on the cell itself). Not sure if intended battery-saving/protection measure (or side effect of one) or just some interaction with how their boost driver works. Luckily momentary turbo from off and all other modes still seems to work fine as low as I’ve let any cells get in it.

derfyled wrote:
One of the most under-estimated light. I never thought I would like it that much. Reliable, solid, beautiful tint, perfect flood. This light is the perfect tool for inspection jobs. Near 2 hours at 1000 lumens is simply amazing. This light is my best purchase of 2019.

Agreed, especially now that it seems all the little finishing issues we saw from the first GB lights are fixed AFAIK. I think the price has turned people off from it, especially with Wuben not being as well known as Acebeam, Olight and other brands with similar lights around the same price. This absolutely smokes the EC65 and Seeker 2 though IMO.

Unfortunately maybe the limited max output vs something like a D4 killed potential interest too, even though you can BARELY see any difference in output and the extended battery and thermal runtimes of slightly limited output is so much more practical.

A hidden gem.

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Great review. We do like our two, very much. Smile

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