Lumintop SD75 (XHP70, 4×18650) Charging/Rechargeble Review: RUNTIMES, BEAMSHOTS+

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The SD75 is a new light from Lumintop, featuring the high-output Cree XHP70 emitter in a large throwy build. Other interesting features are the ability to charge 4×18650 right inside the light, and the option to use the battery pack to charge external devices through the included USB ports.

Let’s see how it compares to the recent AceBeam offering in this XHP70 space, and other competing high-output lights.

Acebeam Reported Specifications:
Note: as usual, this is just what the manufacturer provides. Scroll down to see my actual testing results.

  • LED: 1 x Cree XHP70 LED
  • Output mode / Runtime: High – 4000 lumens / 2 hours 41 mins, Med – 1800 lumens / 8 hours 20 mins, Low – 150 lumens / 50 hours,
  • 4 modes: Low (default) / Med / High / Strobe
  • Peak beam intensity of 106,200cd and throw distance of up to 652 metres
  • Battery type: 4 x 18650 Li-ion battery (2S2P)
  • Intelligent Li-ion battery charging circuit
  • High strength aerospace aluminium alloy construction with anti-scratching type HAIII military grade hard-anodised finish
  • Optimised ultra-precise reflector offers a longer beam distance
  • Double-side AR coated, tempered glass lens resists impact and thermal shock, maximises light transmission
  • Dimensions: Length 248mm, head diameter 90mm, body diameter 52mm
  • Weight: 831g (excluding batteries)
  • 120V/240V wall charger and 12V car charger
  • Time based intelligent thermal management to ensure stable and safe operation (after lighting on brightest mode for 3 minutes, the output ramps down to prevent overheating)
  • Reverse polarity protection to protect from improper battery installation
  • Multi-function, front side switch provides one-handed operation and easy access to all functions
  • Intelligent memory function stores last mode accessed, except strobe
  • Capable of standing up securely on a flat surface to serve as a candle
  • Includes 2 x USB power outputs (1A/2A) and flexi-head USB worklight attachment
  • Battery charge indicator in tail cap
  • Impact resistance to 1.5 metres and waterproof in accordance with IPX8 (submersible to 2 metres)
  • Battery voltage/charging voltage: 6V-8.4V / 12V
  • Two USB outputs: 5V1A / 5V2A
  • MSRP: unknown, but likely >$200


The SD75 comes in a presentation-style carrying case with metal hinges, closing clasps and handle. Along with the light is an AC charging cable and transformer, 12VDC car adapter charging cable, USB-based worklight (warm flood), warranty card, wallet-sized squeeze light, and manual. Note that no extra o-rings were included on my sample.


From left to right: Keeppower protected 18650 3100mAh; Lumintop SD75; Acebeam K60, K40M; Fenix TK61.

All dimensions are directly measured, and given with no batteries installed:

Lumintop SD75: Weight: 825.3g, Length: 247mm, Width (bezel): 88.4mm

Acebeam K60: Weight: 593.2g, Length: 207mm, Width (bezel): 88.0mm
AceBeam K40M: Weight: 498.4g, Length: 188mm, Width (bezel): 76.2mm
SupBeam K50: Weight: 645.0g, Length: 230mm, Width (bezel): 90.1mm
Crelant 7G10: Weight 643.4g (827g with 4×18650), Length: 198mm, Width (bezel): 79.0mm
Eagletac MX25L3C 3×18650: Weight: 345.9g, 352.0g with kit tailcap (485-491g with 4×18650), Length: 141.9mm, 143.6mm with kit tailcap, Width (bezel): 61.9mm
Fenix TK61: Weight: 605.7g (790g with 4×18650), Length: 218mm, Width (bezel): 96.0mm
Fenix TK75: Weight: 516.0g (700g with 4×18650), Length: 184mm, Width (bezel): 87.5mm
Niwalker BK-FA02: Weight: 687.6g (870g with 4×18650), Length: 209mm, Width (bezel): 80.0mm, Width (tailcap): 50.3mm
Olight SR52: Weight: 396.7g (497g with 6xCR123A), Length: 162mm, Width (bezel): 63.1mm
Thrunite TN35 (MT-G2): Weight: 571.4g (723g with 3×18650), Length: 201mm, Width (bezel): 78.9mm

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The SD75 is a slightly more substantial light than the AceBeam K60, with a slightly deeper reflector and extended body to house the tailcap circuitry. Anodizing is flat black, like other Lumintop lights. Labels are minimal, and sharp and clear.

Rather than traditional knurling, the handle has a checkered pattern. Combined with the extra ridge detail on head and the screw-in lanyard point, overall grip is certainly ok. The light can roll very easily, however.

The single control button has a slightly raised metal ring, helping you find it by touch. See below for a user interface discussion.

Screw threads are traditional triangular cut, but seem of good quality. They are anodized, but it is the tension on the spring in the head than determines if you can lock out the light by a twist. On my sample, a quick turn is enough to lock out the light.

The lights can tailstand. Tailcap cover has lanyard attachment points. You can remove the tailcap cover to access the battery readout, in-light charging and externally charging USB ports.

Let’s take a closer look at the battery carrier and tailcap features:

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The positive contact points inside the carrier are slightly raised, so all types of 18650 cells should work fine (i.e., true flat-tops, wide and small button-tops). There seems to be plenty of room in the carrier for length, so longer cells should fit fine. The carrier is in 2s2p arrangement.

Under the tailcap cover, you will find the control area for in-light charging/external USB charging. The tail has a button to read out the 18650 battery voltage, and activate the external USB ports. As you can see, these are rated for 1A and 2A max current, so you should be able to charge just about any USB-based devices from the battery pack. The presentation reminds me a bit of the ZeroHour XD.

FYI, for the bundled USB-based task light, I measured the current draw at 0.22A. That would suggest a runtime of over 1 day on 3100mAh cells (given the 2s2p arrangement).

To charge the batteries in-light, plug in the barrel-plug connector (connected to AC or DC power). There is an LED light on the charging transformer brick that shows green when AC power is present but not charging, and red when charging is occurring. The battery indicator on the tail will ramp through the levels to indicate relative charge status during charging. However, this ramping indicator continues to show charging even when the charger has terminated (as demonstrated by the LED on the transformer brick).

Note that I had some issues on my light with early termination of charging. If this happens, simply un-plug and re-plug the charger, and charging will resume. All told, it took about 5.5 hours to fully charge my 3100mAh cells – but I needed to re-start the charger at least once or twice during each charge attempt. At final termination, all cells read as fully charged, ~4.21-4.22V.

UPDATE SEPT 11, 2015: Lumintop has sent me a revised shipping version of the light, with a corrected charger and increased max output. I am currently testing the light, and will update this review soon with full details. I have performed two charge attempts on the new light, and both terminated successfully with no restarts required. Resting voltage of the cells was consistently ~4.15V, however.


The large XHP70 emitter die shows four quadrants, with very little overhang of the emitter base (i.e., relatively small dome, just covering the die). This should translate into reasonable throw for the size and output. Reflector has fairly heavy texturing (orange peel finish). There is a clear anti-glare coating on the lens.

Scroll down for beamshots.

User Interface

Light uses the standard Lumintop interface – press-and-hold the switch to activate the light or turn off, click to advance through modes. This is the opposite of most lights.

Mode sequence is Lo > Med > Hi, in repeating loop upon repeated clicks of the switch. Light has mode memory, and retains the last level after a press-hold off and on cycle.

A rapid double-click of the switch when on activates strobe. A single click exits. There is no memory for strobe.


For more information on the light, please see my brief overview here:

As with all my videos, I recommend you have annotations turned on. I commonly update the commentary with additional information or clarifications before publicly releasing the video.


There is no sign of PWM on any level – the light is current-controlled.

There is a high-frequency pattern detectable on my oscilloscope on the Med mode:


This is not present on Lo or Hi:


Note that this circuit signal is not visible in any way, There is no flicker or any other visual artifact on any level, even when shining on a fan or running water. Consistent with my review practice, I simply report on any circuit features that I can measure, even if they produce no obvious effect.


Strobe is a fast tactical 16.6 Hz strobe.

Standby Drain

There must be a standby drain when the light is fully connected, due to the electronic switch in the head. I measured this traditional standby current as 292uA on 4×18650. Given the 2s2p arrangement, that would take about 29 months to fully drain 3100mAh cells.

Note that you can break this small current by a simple twist of the head. This will effectively lock out the light.


And now, what you have all been waiting for. All lights are on their respective 18650 battery sources, about ~0.75 meter from a white wall (with the camera ~1.25 meters back from the wall).

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For outdoor shots, these are done in the style of my earlier 100-yard round-up review. Please see that thread for a discussion of the topography (i.e. the road dips in the distance, to better show you the corona in the mid-ground). Note there are a lot of bugs out at this time of year, so expect to see some flight trails.

Sorry about any tint effects – I accidentally left the camera on Automatic color balance for these shots. Note that the Nitecore TM16 (4xXM-L2) will be examined in an upcoming review. Please see my review catalog at for the AceBeam K60, K40M, Eagletac ZP10L9 reviews.

The SD75 does not have the same max output as the K60 recently reviewed. Instead, the SD75 is just slightly brighter overall than a recent MT-G2 light (like the K40M) – but with better throw. Scroll down for direct beam measurements.

Testing Method:

All my output numbers are relative for my home-made light box setup, as described on my website. You can directly compare all my relative output values from different reviews – i.e. an output value of “10” in one graph is the same as “10” in another. All runtimes are done under a cooling fan, except for any extended run Lo/Min modes (i.e. >12 hours) which are done without cooling.

I have devised a method for converting my lightbox relative output values (ROV) to estimated Lumens. See my How to convert Selfbuilt’s Lightbox values to Lumens thread for more info.

Throw/Output Summary Chart:

My summary tables are reported in a manner consistent with the ANSI FL-1 standard for flashlight testing. Please see for a discussion, and a description of all the terms used in these tables. Effective July 2012, I have updated all my Peak Intensity/Beam Distance measures with a NIST-certified Extech EA31 lightmeter(orange highlights).



As you can see above, the K60 is driven harder on max. However, the SD75 still exceeds the max output and throw of the MT-G2 lights.

One interesting aspect here – Lumintop originally planned to use the MT-G2 emitter in this light. Although this version was never released, I did have the opportunity to test an engineering sample. Below is how the shipping XHP70 version of the SD75 compares to the original (unreleased) MT-G2 design.

UPDATE SEPT 11, 2015: Lumintop has sent me a revised shipping version of the light, with a corrected charger and increased max output. I am currently testing the light, and will update this review soon with full details. But my preliminary testing shows a considerable increase in output – now ~3650 estimated ANSI FL-1 lumens (and 114,000cd beam intensity).

These results suggest that the SD75 was never intended to be as heavily-driven as some in this class = but the XHP70 provides a decent boost for both output and throw.

Output/Runtime Comparison:

I currently do all my runtime testing on Panasonic NCR18650A (3100mAh) based protected ICR cells.

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The SD75 shows a period of flat stabilization on all levels, follow by a gradual decline in output. This is a good practical circuit design, as you will not notice any gradual loss in output initially – but will not be left in the dark unexpectedly. You also do not have to worry about potentially annoying low-voltage flashes on this light.

Overall efficiency seems good, comparable to other current-controlled lights in this class (i.e., other XHP70 or 4xXM-L2 lights).

As previously mentioned above, I have an engineering sample of an early MT-G2 equipped SD75. Below is a runtime comparison, so you can see how the XHP70 compares to the MT-G2 for efficiency in the same build.




Potential Issues

As with all lights with electronic switches, there is a stand-by current when fully connected. But this current is reasonably low (292uA), and will not be problem for regular use (i.e., would take over 2 years to fully drain the cells). And you can easily break this current by loosening the head a quarter turn.

Only 18650 Li-ion cells may be used in the light (i.e., doesn’t support multiple CR123A primary cells).

The in-light charger terminated unexpectedly on several occasions, requiring an un-plug/re-plug step at least one. Final termination levels are consistent with fully charged cells (~4.21-4.22V each).

UPDATE SEPT 11, 2015:Appears to be fixed on the current shipping version. I have tested a shipping sample, and two charge attempts both terminated successfully with no restarts required. Resting voltage of the cells was consistently ~4.15V.

The external USB-charging feature and battery read-out stopped working on my engineering sample during testing. No issues were observed on the final shipping sample during testing.

Preliminary Observations

The SD75 is another solid offering in the new XHP70-class of lights.

Part of Cree’s Extreme High Power (XHP) series, the XHP70 delivers twice the output of the MK-R, with similar lumens/watt – and without increasing the overall package footprint. Please see the Cree XHP70 datasheet for more info. The promise of this new emitter is for relatively efficient high-output, and potentially better throw (when coupled with a large reflector) – compared to some of the previous large emitters.

The SD75 is a completely new build from Lumintop, and it seems to be a quality light, with a very solid build. It uses the typical Lumintop user interface, which admittedly is fairly basic. But the SD75 is distinguished by its in-light 18650 charging feature (by AC or DC power, cables included), and ability to serve as a portable power bank to charge external USB-based devices (up to 2A). It even comes with a small warm-tinted work floodlight, with somewhat flexible neck.

The SD75 shows very good output/runtime efficiency, with decent regulation (i.e., mix of flat stabilized and gradual drop-off). Note that you can really see the output and efficiency advantage of the XHP70 over the MT-G2 in this build. Max output is not quite as high as some in this XHP70 class, although it does exceed all the MT-G2 lights I’ve tested.

Beam pattern is relatively focused for throw, thanks to the very deep reflector. That said, it doesn’t throw as far as the recent AceBeam K60, due to the lower max output. Overall, I would describe this as a very “traditional” flashlight beam pattern, but with above-average output for a single-emitter light. I think this XHP class has a lot of potential for heavy-duty flashlights.

For those looking for a good range of features in a heavy-duty, relatively throwy, high-output light, the SD75 is certainly one to consider. I like the extra touches and battery power bank feature. Overall, I would consider this one of the better new product launches from Lumintop.

SD75 provided by Lumintop for review.

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