ThorFire asked me to review their VG15S light, battery, and charger. I agreed with the caveat that I would report whatever I found. I ordered it from Amazon at a discounted price, meaning I received a light without any special preparation. Many thanks to ThorFire for giving me the opportunity to do this review.
The ordering and delivery process was the typical no problems Amazon experience. At the time I ordered the package price on Amazon was just under $30. This is worthy of note because it places the light in a price class normally found by shopping from far away sellers with long delivery times. This easy ordering, along with the complete package to get up and running, makes this an interesting starter set for those just entering the world of 18650 powered lights. Could I recommend this to friends who saw my lights but were put off by the investment in support equipment required? I put the light into my EDC rotation a few months to find out.
The light, battery, USB cable, spare O-rings, and charger arrived in a small tan cardboard box. Everything was packaged well and there was no shipping damage. This is typical packaging for lights of this type, but was above the bubble wrap in an envelope used by many inexpensive Amazon sellers.
The Light
Manufacturer Specifications:
After unpacking, I put in a charged battery that I had on hand and turned on the light. The light has a very low firefly level and a very bright turbo mode. Mode changes are easy with a partial click on the tail switch, never skipping a level from an uncertain switch. The single frequency strobe is hidden but easy to enter if desired. Mode changes are slightly different from other lights with a moment of darkness between levels. It is so short that it does not affect the usefulness of the light and is not an issue, but it does show in some runtime graphs presented later in this review.
The textured reflector gives a smooth, even beam. I found it very well suited for indoor use, with the hotspot to spill transition very smooth and only visible when shining on a white wall. The color temperature is not specified but it is just cooler than neutral. I am not a huge fan of the yellowish tint of warm LEDS so this was very good for me. Outdoors the bean does well, with colors slightly shifted to the cool side of the range by the emitter color. This is mainly noticeable when looking at beam photos to look for color accuracy.
I set up my tripod mounted camera using fixed exposure settings for outdoor beam photos. I chose settings that gave the image that best matched what I saw in person. Firefly mode is so dim it does not show on the photos and is not included here. It is just enough light to navigate the house with eyes fully adjusted to the dark. The light is mounted above the camera. All beam photos use the ThorFire 18650.
Level 2 – Low
Level 3 – Mid
Level 4 – High
Level 5 – Turbo
To make more sense of the turbo photo, I’ve added distances to the objects. There are trees at 150 and 200 feet, and a house at 440 feet. To verify the claimed throw distance, the light illuminated a house 520 feet away. There are no photos of this test as it was done quickly to avoid annoying the neighbors.
I used the Ceilingbounce app on an S5 cell phone, along with a white box, to get relative brightness measurements using the supplied 18650.
The turbo mode specifies a 3-minute timed stepdown, and this is accurate. The light can be put back into turbo when it steps down. For this test, I let turbo step down, then went back, then ran through the modes in order. High is bright enough for close tasks, while turbo really reaches out to see things farther away. Using the app again, I compared the VG15S with ThorFire cell to an Astrolux S1 with an HG2 18650. This light is generally considered to be 1200 lumens on its highest mode and 800 lumens when it steps down. The graph shows that the VG15S on turbo is between these two levels, supporting the advertised lumen rating.
I could not see any difference between my HG2 and the ThorFire cell, but I checked the two in the box. The measurements showed no real difference.
After multiple 3-minute runs on turbo, the light became warm but not too hot to hold. The heat was transferred through the head into the body tube. Here is the light after this test, on an insulating pad in a 70F room. During the test, I could see the head heat and then watch the warm area move toward the tail of the light. All temperatures are in degrees F. The emissivity setting for anodized aluminum is not a good match for the wood desk, which shows 88.2F.
After a few weeks of carry and use, I took the light apart for photos. The finish showed minimal scratches even after bouncing around in my bag with other lights. After these photos, I finally managed to mark the black finish but it was an accidental 4 foot drop onto concrete that dented the aluminum of the tail slightly. Threads were well machined, turned smoothly, and arrived lightly lubricated. The O-rings fit properly and did not pinch or move out of place when tightened down.
The only flaws I found were in the side recesses. They showed some machining marks and one area of thin anodizing. I believe this was atypical. Someone who saw my lights (VG15S and TK15S) at a geocaching event ordered the VG15S set for himself and it was without visual flaws. I purchased (at normal price) a VG15S set as a gift for a relative. It also did not show any machining or anodizing defects. I’m sure I could have returned my light to Amazon but I am not bothered by such details.
The internal construction is good, with thermal paste under the star and no dirt inside the light. The driver is held in with a brass ring, as are the tail components. The star is held in place by the pressure of the metal reflector. I did not disassemble the light further, but it should allow easy modifications. The dome of the XM-L2 was clean and unmarked.
With the light apart, it was time for measurements. The removable reflector allowed measurements at the driver with the light running. This simplified the measurement process.
Using my DMM for low current levels and a DC clamp meter on a short wire shunt for the higher levels shows that the ThorFire cell performs well, but does not allow the tail current of the HG2. The ThorFire is a protected cell so this may not be a fair fight. I compared to an older unprotected cell for another data point.
Measuring DC voltage across the LED while running lets us estimate the current out of the driver and then the lumens emitted using the CREE datasheet.
By eye I could not detect evidence of PWM and user reports on the internet supported this. I checked voltage at the LED with an oscilloscope and found something interesting. Firefly and turbo showed DC voltage as expected, but the levels in between showed a nearly 1V 21kHz signal riding on the DC voltage. Is this PWM that does not turn off the light? I sent a note to ThorFire but have not yet received a response.
Firefly
Low
Mid
High
Turbo
The Battery
The ThorFire protected 18650 performs well, but what is it? ThorFire calls out a Samsung cell, and through the orange areas of the wrapper I could see most of the OEM numbers on the battery. ICR18650-30___. Under the wrapper the cell’s OEM color is light green. This sounds like ICR18650-30B but I have not unwrapped it to be sure. Checking a second ThorFire cell, I could see __________-30B under the wrapping. This supports the Samsung -30B identification. Testing on my Opus BT-C3400 charger using the charge/discharge capacity test showed 2700mAh when the cell was new. My HG2 also read just under its rated 3000mAh so I was happy with the ThorFire cell. There are many stories of exaggerated ratings on mail-order cells. I am glad to see that does not apply to the ThorFire cell I received.
The Charger
The supplied charger achieves its small size by running on a 5V USB power supply (not included). I used a high current supply for my testing. The charger was simple - connect a USB power supply capable of 1A, insert the battery, and watch for the LED to change color. The charger initially did not work, which I traced to a faulty USB cable supplied with the unit. Using a known good cable allowed charging without issues. Multiple measurements charging with the ThorFire charger and measuring capacity via discharge on the Opus showed the ThorFire charged their cell to approximately 2300mAh. I keep the ThorFire charger in my work bag, but I use desktop chargers whenever possible. The charge info shown in the images is from the ThorFire site. The back of the charger says 750mA charge current. The charger is specified for 18650, 26650, 16340, 14500, and 10440 cells.
Summary and Opinion
PRO
Light and battery perform as advertised
Good construction
Easy disassembly for modification
Inexpensive
Good color
Good beam
Charger is a good size for travel
CON
My sample light had some finish issues, not seen on other lights
Charger seems to cut off a little early
Defective USB cable on my charger
I did not know what to expect from a low-cost light with an unknown battery. I am pleased with the performance of the light especially at this price point and quick availability. The light went to Boy Scout meetings and camping, geocaching, and to work in an industrial setting and always impressed those who saw it. The rest of the time it bounced around in my work bag. Through all that abuse it held up well. While not a lumen monster, the good turbo runtime, useful high setting, and smooth beam make a very good light especially for indoor or other close work. I feel it is a very good intro light for someone who does not already have many batteries and chargers and who desires simple operation. A light with low voltage warning using a protected cell makes for a reasonably safe setup. Two of my friends have purchased the light for their use. I find myself carrying this light if I will be with a group because I can lend it to someone without the 5 minutes of instructions and warnings often required for custom “enthusiast” lights. In fact, I was so pleased with the light that I bought another one at regular price to give as a gift to a family member getting started with 18650 lights. A number of friends purchased one for their own use after seeing mine.
Test Equipment
BT-C3400 Opus charger
Ideal 61-768 clamp meter
Protek 506 DMM
Fluke Ti32 thermal imager (E=0.85)
Fluke 199C scope meter
Zeiss Stemi 1000 microscope
Pentax K50 camera