# Object/Subject Review: Sunwayman T20CS



## Bigmac_79 (Dec 17, 2011)

Sunwayman is quickly becoming one of the top flashlight makers around. They are well known for a sleek look to their lights, and not compromising on quality. Their V series lights are the essence of simplicity in a UI. Recently Sunwayman released the T40CS, a foray into the realm of "tactical" lights. Now, they've made available the T20CS, the little brother to the T40CS. The T20CS is a compact thrower, using the top-of-the-line Cree XM-L U2 emitter in a large head with a deep reflector. Also, the T20CS features a side switch and a low voltage indicator light, which sets this light above the norm in this category.

_Thanks to Sunwayman for providing the T20CS for review.
_






I’ll be reviewing the T20CS in two sections: first, I’ll discuss the light objectively (the facts about the light itself), then I’ll discuss the light subjectively (my impressions about the light's performance when used for specific applications). Sunwayman classifies this as a "tactical" light, so the subjective portion will look at it from that point of view. If you have any other specific applications you'd like the light tested for, let me know and I'll see what I can do.


Objective

Here are Sunwayman's specs on the T20CS:

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● CREE XM-L U2 LED, with a lifetime of up to 50,000 hours;
● Tactical Tail cap press button switch, slightly depress the side switch for different output modes and standby mode:
One Turbo Mode, Three Modes constant output, Hidden Strobe and SOS functions (below is the output and runtime of using two CR123A batteries or one single 18650)
Turbo Mode (2*CR123A batteries): 658 Lumens (68min)
Three constant output modes (1*18650 battery): 476Lumens (2.5hrs) - 92Lumens (11hrs) - 18Lumens (82hrs)
Strobe: 476 Lumens
SOS: 476 Lumens
● Constant current circuit, constant output
● Effective range of 278 meters
● Uses one single 18650 or two CR123A batteries
● Working voltage: 2.5~10V
● High quality metal smooth reflector maintains great throw distance and spread with an ideal beam pattern
● Dimensions: 140mm (length) x 38mm (head diameter) x 25.4mm (tail diameter)
● Weight: 124g（battery excluded）
● Aerospace-grade aluminum alloy, Stainless Steel retaining ring on the top
● Military Specification Type III- hard anodized body
● Waterproof, in accordance with IPX-8 standard
● Ultra-clear tempered glass lens resists scratches and impacts
● Tactical forward click switch for momentary on
● Accessories: tactical ring, holster, O-ring, rubber cap,lanyard

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*
Packaging
*
The T20CS comes in a cardboard box that looks like it could be standard for many different Sunwayman lights, with a sticker on the side with the model number and a few specs.










Upon opening the box, you find the light nestled in some soft foam material attached to the box, and a sticker telling you that there is more stuff underneath the packing material. Included is the T20CS user manual, warranty card, ad card for other SWM lights, holster, lanyard, spare switch boot, and spare o-rings.


*Construction Quality*

This light feels extremely solid and well made, and has the attention to aesthetics that we've come to expect from Sunwayman. 

Here's the T20CS compared in size to a 18650 battery:






As you can see, the battery accounts for a little more than half the length of the light, with a lot of length devoted to a deep reflector on the head for long throw.
















The head has a mildly aggressive look to it, with a smooth stainless steel bezel. The side switch is a small black rubber button on the same part of the light that houses the emitter. To either side of the button you can see the fins that Sunwayman has put in for heat dissipation. They're a little smaller than you world normally see for cooling fins, but the head of the light itself is large enough to add a lot of surface area for cooling. The anodizing is dark grey color with just a hint of olive green when you look at it in the light, but otherwise just seems black at first glance. The lettering on the body is white and clearly printed, with the SWM logo on one side and the model number on the other. A rubber grip ring is included on the body. The tail cap has a bit of knurling to help with battery changes; this is the only knurling on the light. The switch extends well beyond the tail of the light, making it very easy to find and press, but making it impossible for the T20CS to tail stand.

Here's a shot of the side switch from the side, you can see it has a very low profile, so you shouldn't have to worry about it getting caught or worn away on anything.






On the side of the head, opposite the side switch, is the low voltage indicator, a red LED, inside a clear window into the head of the light. The indicator is flush with the head. I've included a description of the low voltage indicator in the "Performance" section of the review.









The grip ring on the body is made of a firm rubber. It can be moved to either end of the body with mild resistance, but I couldn't remove it from the body without applying more force than I felt comfortable subjecting it to. The detailing on the head of the light also provides a good amount of grip on the light.









The T20CS unscrews by hand into four pieces. (I was also able to unscrew the bezel by pressing it against a piece of rubber, making bezel replacements possible.)














You can see it has o-rings at each detachment to prevent water from getting in. All the threads are square cut to make them last longer and give a better feel to screwing and unscrewing each part. Most of the threads are anodized to improve durability, and on the tail cap it allows the light to be locked out (pressing the switch won't turn it on in your pocket or bag) by unscrewing it only about 3 degrees. Having such a small amount or turning need to put the light into lockout means the tail will still be very secure when in lockout mode, but it also means you have to be very sure the tail is fully tightened when you are ready to use the light, because there is small room for error. Having the threads between the body and head left bare will improve the electrical connection and allow the light to work even if not fully tightened in that area, but they will wear down faster. However, you shouldn't need to be unscrewing that part too often, because battery changes can be done at the tail (which has less friction anyway).









The rubber boot on the tail cap is imprinted with the Sunwayman logo, like most of their lights. There is a spring inside the tail for the negative batter contact. This is a forward clicky switch. Forward clicky switches allow momentary on by half-pressing the switch or constant on by with a full-press, clicking it into position, but tend to wear out a little easier than reverse clicky switches. 









The head also has a spring for the positive battery contact, so the T20CS is set up to accept a wide range of battery lengths and also not loose connection during impacts. The emitter sits in the middle a white plastic housing. Because the reflector can be easily unscrewed from the rest of the head, you can use the T20CS in "candle mode" with the bare emitter, and it is recessed inside the head enough to still give it a slight amount of protection. However, it will no longer be waterproof, and will be vulnerable to scratching up the emitter. The T20CS uses the U2 binned XM-L emitter, which is on average about 7% brighter than the T6 bin, the most commonly used bin for high-quality lights in this class at this time (12/21/12).












You can see the underside of the emitter here, it fits nicely into the plastic housing and over the emitter. The use of plastic instead of metal is probably to keep heat from transferring directly into the reflector, and instead direct it to the outer body of the light, where your hand take take it away. The reflector on the T20CS is very smooth (SMO), as opposed to an "orange peel" (OP) texture. An OP reflector will make the beam look smoother by scattering out the light a bit, but an SMO will throw the light farther by not scattering it out. SMO reflectors typically show more rings, unevenness, or other artifacts in the beam, but on a light designed to throw long distances, this isn't too important. You can see the "Action Shots" section for pictures of the beam. 

Here's some shots of the T20CS in the included holster. It's the typical SWM style holster, velcro for both the front flap and the belt strap, and the SWM logo printed in red on a tag.









The lanyard included is the typical SWM style lanyard. A lobster-claw attaches the lanyard to the light, a tab on the end of the lanyard, and an adjustable slider in the middle. A metal ring with a protrusion for the lanyard is included to be put on the light when you want to use the lanyard, because there is no lanyard hole anywhere on the T20CS.









There are two points where the lanyard ring can slide onto the T20CS, between the body and tail or between the body and head. However, between the body and tail the ring is very loose, because the body and tail don't pinch together on it. Between the body and head, the lanyard ring is very tight, but...






As you can see by this picture, I damaged the anodizing and o-ring trying to get it on. The diameter here must be slightly larger, because I had to push to get the ring on and it scratched things up a bit. There were no instructions or pictures included about where the ring is supposed to go, but I'm going to recommend putting it in between the body and tail unless you want to try to stretch it out with a tool to fit up by the head better.


*User Interface*

First, I'll clear something up from Sunwayman's specs on the T20CS. According to Sunwayman, the T20CS has Turbo, High, Medium, and Low modes, with hidden Strobe and SOS. On my reading of the specs, it sounded like Turbo was not available when using 1x18650. However, as you can see in the graphs below, it does do Turbo mode, just not regulated, and it's not much different from High mode.

The T20CS has two switches, the "forward clicky" tail switch and the "soft press" side switch.

To turn the light on, you first have to press the tail switch. If the tail cap switch is off, the side switch doesn't do anything. Whenever you press the tail cap switch, it will put the light in Turbo mode. Because it's a forward clicky, you can do a half-press for momentary Turbo, or a full press for constant Turbo. Once the light is on, you can either turn it off by the tail cap (and the side switch will continue to do nothing) or you can turn it off by a single press to the side switch which will leave the light in a sort of standby. When in standby, the light can be turned on by the side switch. The side switch always starts in High mode, and by holding down the side switch for about a second you can cycle High-Medium-Low. Turbo cannot be accessed by the side switch, you need to click the light off then back on by the tail switch. Also, when the light is on or in standby (the tailcap switch is fully pressed), you can do a quick double-click on the side switch to go into strobe mode. When in Strobe mode, you can do another quick double-click on the side switch to go into SOS. Turning the light off by either switch at any time will deactivate the Strobe or SOS and take you back to the regular UI. 

There is a sort of mode memory. When you set the light to either High, Medium, or low, then turn it off by the side switch, it remembers the mode you were in and turns back on in that mode when you hit the side switch again. Turning the light off by the tail switch clears the mode memory. If you use the strobe or SOS modes, they will be ignored by the memory: they will not be remembered and will also not clear the memory. So, if you have it in High, Medium, or Low, then switch to Strobe or SOS, when you turn it off then back on by the side switch, it will go back to either High, Medium, or Low, whichever you used before activating the strobe.

A video showing the various aspects of the UI:



*Action Shots*

The T20CS in hand:










White Wall Beam Profiles:
_(photos taken at ISO 100, f/6.3, 1/4")
_
Low, Medium, High, Turbo



















The T20CS outdoors: 
_(photos taken at ISO 100, f/6.3, 15")

_Barn; ~35 yards; Control, Low, Medium, High, Turbo





















Barn; ~100 yards; Control, Low, Medium, High, Turbo





















Barnyard, Yard; Turbo









Silo, ~1/3 mile (zoomed in), Control, Turbo








(you might have turn up your monitor's brightness for this one, it appears brighter than this in real life)

Bike Path, Control, Turbo
(ISO 100, f/3.3, 5")



























*Performance*

I submerged the T20CS in about a foot of water, and clicked both the tail cap and side switches several times over the course of 10 minutes, with no evidence of water entering any part of the light, so it does appear to be waterproof.

Sunwayman claims this light to have a "constant current circuit", which means no pulse width modulation. I could find no trace of visible PWM on any mode, and no audible whine or buzz.

Sunwayman's specs for the T20CS mention using the light with 2xCR123 or 1x18650, but they also state that it can handle up to 10V. So, I've tested it with 2x16340 lithium-ion cells as well (total 8.4 V fully charged). As you'll see, this gives it super short runtimes and the low voltage indicator doesn't work, but the light does operate just fine, so this is an option if you want it.

Low Voltage Indicator

The T20CS features a red low voltage indicator LED on the body of the light, opposite the side switch. This LED kicks on when the battery reaches a certain voltage, then starts flashing at about 2-3 flashes per second when the battery hits a lower voltage. In my tests, I found the voltage that turns on the indicator to be different for each level. On the turbo and high modes it just goes straight from off to solid on to flashing. On the medium and low modes, there is a time when it sort of flashes intermittently as the battery approaches the voltage that activates the indicator, possibly because the voltage wavers as it sags. Then, as it is solid and approaches the voltage where it will strobe, it will flash intermittently for a while before going into a steady flash, presumably for the same reason. Below is a video of the indicator going to solid then flashing, and the results from my tests showing at what voltage the low voltage indicator lights up:



_1x18650
_Turbo: Solid at 3.38V, Flashy at 3.13V
High: Solid at 3.33V, Flashy at 3.04V
Medium: Solid at 3.08V, Flashy at 2.91V
Low: Solid at 3.01V, Flashy at 2.87V

_2x16340
_The low voltage indicator did not come on at all, in any mode, before the protection circuits in my 2x16340 cells cut them off. Instead, the XM-L emitter just started flashing, presumably to let me know the driver was no longer able to pull the necessary current out of the cells. I suppose that SWM designed it this way to avoid having the low voltage indicator come on when you pop in two fresh CR123 primaries. Below are the volages when the emitter started flashing using my 2x16340 cells, but this might be different for different brands of cells, if the driver is sensing a current drop instead of a voltage drop, as I suspect. Also, once the emitter started flashing, I was not able to switch to any different modes.
Turbo: 6.55V
High: 6.33V
Medium: 5.82V
Low: 6.23V

Current Draw

These measurements are made at the tail cap within a few seconds of turning on the light with fresh/fully charged batteries.

_2xCR123 Energizer_
Turbo: 1.55A
High:  .945A
Medium: .192A
Low: .047A

_2x16340 Ultrafire ICR_
Turbo: .998A
High: .620A
Medium: .162A
Low: .035A

_1x18650 Trustfire ICR_
Turbo: 1.96A
High: 1.092A
Medium: .207A
Low: .055A

Runtime

Note: The vertical axis of these charts represents a relative brightness measurement using a home made light box. The horizontal axis is time in hours:minutes:seconds. Runtimes are stated in hours:minutes.

This first set of charts compare the output of different batteries on each mode. On each mode I tested the T20CS with 2x16340 Ultrafire 880 mAh and 1x18650 Trustfire 2400 mAh. I normally don't use CR123's for runtime tests because of the expense, but I went ahead and did for the turbo mode here. When the 2x16340's finish, they rapidly drop output then go into a trobe mode, fast at first, then slowing down. The 1x18650 just gets dimmer as the battery runs down. On 2xCR123, the light gets dim, then starts a sort of "pulsing". It doesn't blink on and off, but rather pulses it's out put slightly, and the pulsing gradually gets dimmer.

*Turbo *(*Graph truncated to show detail*)





Turbo 2xCR123
Time Regulated: 0:38:04
Time to 50%: 0:39:39, 1:03:03 (drops past 50%, then back up, then down again)
Time until "pulsing": 4:26:44
Full Runtime: 27:30:00 (approximately)

Turbo 2x16340
Time Regulated: 0:19:17
Time to 50%: 0:19:47
Time Until Blinking: 0:27:16
Full Runtime: 1:11:51

Turbo 1x18650
Time Regulated: 0:01:09
Time to 50%: 1:31:33
Full Runtime: 4:52:53


*High*





High 2x16340
Time Regulated: 0:29:30
Time to 50%: 0:29:35
Time Until Blinking: 0:30:11
Full Runtime: 0:45:46

High 1x18650
Time Regulated: 1:02:35
Time to 50%: 1:56:30
Full Runtime: 6:36:03


*Medium*





Medium 2x16340
Time Regulated: 1:56:40
Time to 50%: 2:10:38
Time Until Blinking: 2:11:22
Full Runtime: 8:15:10

Medium 1x18650
Time Regulated: 10:50:59
Time to 50%: 11:04:19
Full Runtime: 14:30:22


These next two graphs are comparisons of the output of the different modes on each battery type.

*2x16340*




The T20CS blinks as the 2x16340's wear down.

*1x18650*




The T20CS gets dim as the 1x18650 wears down.




Subjective Review

*General*

Overall, the T20CS is another great offering from Sunwayman. It's got a great combo of function and style that is hard to beat. 

Here are some of the highlights of what I like about the T20CS:
-compact with high output and long throw
-smooth reflector for throw
-"candle" mode
-low voltage indicator
-UI is reliable, no flickering or mode mistakes
-accepts many batteries
-attractive anodizing color and body design
-easy tail cap lockout (only a few degrees of rotation needed)
-side switch has a traditional flashlight feel
-great tint for a U2 bin!
-minimal rings/beam artifacts even at close distance

Here are a few things that aren't so great:
-inefficient regulation on 1x18650
-complicated UI
-on 2x16340, the XM-L strobes instead of using the low voltage indicator, and cannot switch down to a lower mode
-on 1x18650, low voltage indicator comes on a little too late

Now for some explanation of these.

I've seen too many lights with large heads that are obviously designed to be throwers, but for some reason the manufacturer gave it a textured reflector instead of SMO. I don't know why anyone would do that, if you want to throw, make it throw. At long distances, nobody's going to be bothered by imperfections in the beam. Sunwayman's done the right thing with the reflector here, thrower all the way. And even at close distances, there are a few rings and beam artifacts you can see on a white wall, but even then it's not so bad as to be distracting. The emitter is well centered and the reflector is well shaped. Also, the tint on these is great. All other U2 binned lights I've seen have been severely tinted. This is a cool white for sure, and you can see a little pinkishness to the beam on a white wall, but for the most part the beam is just cool white, and I like that.

The candle mode is nice, it gives a great even flood over the room for indoors use. With the head on, it's pretty hard to use the light at close range because the spot is so bright compared to the spill. While the T20CS wouldn't be my first choice to use indoors, it's nice to have the option to take the head off and use it for flood if it's the only light I have with me. Having the emitter recessed a bit helps keep the beam from getting in your eyes at that point, too.

The performance on 2x16340's isn't too shabby, considering Sunwayman doesn't officially list them as a power source for this light. They are very well regulated, and the brightness hardly drops at all before the cells are depleted. I don't like that it strobes and gets stuck on the current mode when the batteries get low. If Sunwayman wants to officially support these in this light or a similar one in the future, they'll have to find a way to activate the low voltage indicator at a limited voltage range up there, in addition to the low voltages for 1x18650.

The performance on 1x18650 is better than I expected, but I'd still like to see the regulation be a bit better. With the low voltage indicator, there's no reason for the light to dim before it turns off, that's just a waste of energy. On lights without a low voltage indicator, the dimming helps let you know it's time to replace the battery before the light just shuts off. With the T20CS, I'd rather have flat regulation to get maximum brightness as long as possible, and let the low voltage indicator tell me when the battery is low. That same idea goes for using 2xCR123.

On the topic of the LVI, we've had a bit of a discussion in the posts below, which you can read for more details if you like, but I'll just give my summary here. The voltage that turns on the LVI varies between modes from about 3.4V to 3V. Lithium-ion cells have a useful capacity range from 4.2V to about 2.5V or 2.8V, depending on the brand of the cell, and that's usually about when a protected cell will turn itself off. In general it's better not to rely on a protection circuit, especially at low currents, because they don't always work perfectly, and it's not good to discharge your lion past that point. Also, it's recommended to not store you lion at voltages below at 3.8V. So, my conclusion on the LVI: it's useful for letting you know when you really need to stop using your cells, and they *should* not be damaged by being depleted to the point where the LVI on the T20CS comes on or starts flashing. However, when it starts flashing, you should probably stop using the cell and charge it up right away, especially if you're not using a protected cell. Ideally, the LVI could come on solid at a higher voltage (around 3.7V maybe) to let you know that you'll need to charge your battery before you store it, then start flashing around 2.9V or 3V. So, while not ideal, it does the job of letting you know when you need to switch to a different battery just fine.

The UI on the T20CS is very different from what's making Sunwayman popular, their simple and intuitive control ring lights. This UI is definitely not simple, but it manages to accomplish a lot of function in a package that works well together. You can always get to max output quickly, but lower modes are still available for extended run time. It's got strobe and SOS available, but they don't get in your way if you don't want them. Few things are more annoying than having to cycle through a strobe mode in order to get to low, and with the T20CS that won't be a problem. Before reading the manual I played with the UI a bit just to form an impression on my own, and once I accidentally activated the strobe when I didn't want to. That's not fun, but I just turned it off, and when I turned it back on it was no longer strobing, so I was happy. This UI takes a little time to learn, but not much. I can't hand it to a friend and have it just work for them, but I can explain it to them and they can master it within 5 minutes. I'll put more details in the "Tactical" section of the review, but for now just know that while it isn't a "simple" UI, it works well and is fairly intuitive once you learn it. 

I appreciate the effort that went into designing this light, and the attention to detail is great. This is the sort of light that I can count on working well every time, and look good doing it.

*Tactical*

"Tactical" is a word that get's thrown around a lot, and everyone has their own idea on what a "tactical" light should be. Before writing this I did a fair amount of research on old threads looking into what the CPF community in general thinks a tactical light ought to be, so this is a combo of that and my own opinion.

When it comes down to it, a tactical light is one that can be used to execute tactics. You have a plan, and the successful execution of your plan depends at least in part on your flashlight working as you plan for it to. What you look for in a light to use for your tactics depends largely on what you're trying to do, and the environment you'll be in. For example, sneaking up on enemies will require a flashlight that has a low low available easily, searching a crash site for survivors requires a light that has a high output available easily. Indoors or close up you generally want a floody light, outdoors or for long distances you generally want a hotspot that can throw far, etc. So, the appropriate light for your tactics will largely depend on what you're trying to do. However, a few things remain constant for all lights in the "tactical" class...

1. Reliability. In order to be able to rely on your light to be a part of your tactics, you need to know that it will do what you expect it to. Flickering, entering the wrong mode, not turning on, accidentally turning on, etc., is not acceptable. The light needs to work just like you expect. Many people desire simplicity in a tactical light, which is understandable, but not necessary for all situations. A complex UI can be very useful if you know it well. Complex devices are useful in tactical situations all the time, it's up to you to decide whether or not your situation needs a complex flashlight or a simple one.

In this area, the T20CS does very well, because it can operate either as a simple device or a complex one. For a simple UI, just use the tail cap switch, and never touch the side switch. Max brightness all the time, silent momentary on or click into constant on. Simple.

If your situation needs a more complex device, the T20CS can do that with the side switch. Turn the T20CS on with the tail cap switch, then off with the side, and you are in standby mode, ready to enter into any mode you like. A key feature here is that you don't have to mess with strobe modes when you don't want them, but if you use strobe frequently, it's quick to get to with a double click on the side switch. One downside here is that when using the side switch, you can't get to max output as quickly as I like. In order to get to turbo mode when you've been in one of the other modes, you have to click the tail cap switch off then back on again. I'm not sure how that could have been designed differently, but it's something to keep in mind. In general, though the UI with the side switch is complex, you can learn it easily, and it will perform as you expect it to when it counts. Consider it part of your training for your tactical situation.

2. Durability. A tactical light needs to be able to stand up to whatever stress the environment is going to put on it. Again, this varies depending on what you're doing (a dive light needs different qualities than a light being used around EM pulses), but in general you know you want it to be impact resistant, sturdy, water resistant, etc.

The T20CS does very well here. Not to much to say, other than it's a solid light, and I feel confident it won't break easily. You can keep an eye on the "Long Term Impressions" section for any updates in this area.

3. Adaptability. While a tactical situation means you are executing a pre-formed plan, we all know that things don't always go according to plan. Equipment you use in a tactical situation needs to not only be enough for your plan, but enough for any possible/likely bumps in the road. 

The T20CS is fairly adaptable, probably more so than many lights called "tactical". As I mentioned earlier, the UI can either be just a single mode with momentary or constant on, or if needed you can start using the other modes as well. If your situation changes, you have one light with the ability to fill many roles. Also mentioned earlier is the candle mode, for a floodier style light. While not the ideal solution for switching from throw to flood, it works in a pinch. Finally, the many battery combos available make it adaptable as well. I plan to use 1x18650 for most work with it, and have 2xCR123 available in case I don't have time to recharge my lions.

In the end, only you can decide whether this light is appropriate for you tactics. My opinion is, it's definitely a good one to have as an option 

_Note: As of Dec. 2011, Sunwayman has announced two remote pressure switches that would be compatible with the T20CS, but are not yet available for purchase, the AP01 and AP02.
_*
Thrower*

As you can tell from the beam shots, the T20CS is a great thrower, with very respectable spill on the side. I found that I could see objects very far away lit up very well, and was still able to illuminate the area around me. The T20CS isn't pure throw, the reflector could be tweaked a bit more or the head made slightly larger in order to send more light down the hotspot. However, for such a compact size, it throws great. Personally, I wouldn't want to make it much more throwy, I like that I can still see what's going on near me. 

I was most impressed when the T20CS was able to light up the silo that was about 1/3 mile down the road. It wasn't extremely well lit, but I could see that it was there, and I could see it well enough to detect whether or not there was movement on the face of it. In normal use, I found that I could see well what was going on at about 225 yards, and identify objects at about 275 yards.

So, while not a purely throw dedicated light, you'll be hard pressed to find a better thrower in such a small size, and the amount of spill it has makes it useful for more tasks as well.

*Long Term Impressions*

I'll fill this part in after carrying the light for a while. If nothing get's added here, either I find nothing else worth noting about the light, or I end up not using it often.

2/8/12
-I appreciate the instant turbo from the tail cap more and more every day. I recently took some beam shots in a sketchy part of town, and liked knowing that I had turbo quickly available without having to fumble for it.
-The grip ring gets caught in the holster a bit some times, which I don't like because it makes it hard to pull the light out quickly. Not a huge issue, but I do wish it came out easier. I wouldn't want to remove the grip ring, because I really like the good grip.
-Here are some bonus beam shots for fun:


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## tobrien (Dec 18, 2011)

*Re: Object/Subject Review: Sunwayman T20CS (In Progress)*

i'm looking forward to your thoughts on this light, especially the low voltage indicator!


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## RCLumens (Dec 18, 2011)

*Re: Object/Subject Review: Sunwayman T20CS (In Progress)*

Many thanks for this GREAT review! I'll be checking back to see the rest of it since I have my eye on this light. The size, shape, output, ui, battery life all seem good. I'm ok with running cr 123's if that gets the right output, but it seems as though actual runtime might be less than what they advertised. This is great to see thanks again!


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## madecov (Dec 18, 2011)

*Re: Object/Subject Review: Sunwayman T20CS (In Progress)*

Looking foreward to a full review. This light is on my short list along v40 version


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## Bigmac_79 (Dec 19, 2011)

*Re: Object/Subject Review: Sunwayman T20CS (In Progress)*

Posted some more measurements, and a description of the low voltage indicator.


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## Lou Maan (Dec 20, 2011)

*Re: Object/Subject Review: Sunwayman T20CS (In Progress)*

Hi Mac, it would have been nice if SWM had made it where a seperate LED on the side of the body blinked slowly when it reached 3.80, then faster at 3.70 etc. Or how's this for a concept: have a little digital LED that gives you the exact voltage at all times! press a button for a dim blue backlight. Hmmm... who wants to start a flashlight company with me? Sorry for my arrogance, it just seems that I'd like to 'know' a little beforehand, who's with me on this one? The only time they got it right was with the M40C at around 3.67 V, the light comes on. They have the technology. I mean why not use it on ALL the lights?


----------



## Lou Maan (Dec 20, 2011)

*Re: Object/Subject Review: Sunwayman T20CS (In Progress)*

Forgot to say... really nice review shaping up!


----------



## lanternetactice (Dec 20, 2011)

*Re: Object/Subject Review: Sunwayman T20CS (In Progress)*

i got this flashlight 1 week ago. excelent flashlight, better than Olight M21X and Thrunite TN10.

I make some test outside, and i think so this flashlight will have a huge success.

i like how to change the intensity, it's easy, beautyfull smooth reflector, and last but not least it's a beautyfull flashlight. I love Sunwayman because they give a very good look for flashlight.


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## Bigmac_79 (Dec 20, 2011)

*Re: Object/Subject Review: Sunwayman T20CS (In Progress)*



Lou Maan said:


> Hi Mac, it would have been nice if SWM had made it where a seperate LED on the side of the body blinked slowly when it reached 3.80, then faster at 3.70 etc...



This is actually what it does, except not at those voltages. There is a small red LED on the side of the body that turns on when the battery gets low. I'll edit my description of it to make that more clear.

Your other ideas sound good too, though no doubt more expensive to implement


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## Bigmac_79 (Dec 20, 2011)

*Re: Object/Subject Review: Sunwayman T20CS (In Progress)*

Alrighty, I updated the description of the low voltage indicator to be a little more clear, and added details on the mode memory in the UI.


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## spc smith (Dec 20, 2011)

*Re: Object/Subject Review: Sunwayman T20CS (In Progress)*

great review bigmac 79! I look forward to the beamshots! thanks for taking the time so that all of us that dont have it yet can subjectively make a decision to buy ...or not to buy.. that is the question lol


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## RCLumens (Dec 20, 2011)

*Re: Object/Subject Review: Sunwayman T20CS (In Progress)*

Very nice review BigMac! Looking forward to the beamshots also!! Looks like this type of light-class is going to be next in line... Apparently the market's calling for longer throwing brighter tactical lights... Just saw a posting for the Klarus XT11... looks like another potential contender in this class of light - depending on throw. That's the part I'm most anxious to hear about from your review. Hoping to hear 220 yards with good visibility. 

Cheers!! RC


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## Bigmac_79 (Dec 20, 2011)

*Re: Object/Subject Review: Sunwayman T20CS (In Progress)*

Thanks for the positive feedback! I'm waiting for a good night to do outdoor shots, it's been rainy for about a week. Really, it ought to be at least snowing by now, but no, just rain.


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## Lou Maan (Dec 20, 2011)

*Re: Object/Subject Review: Sunwayman T20CS (In Progress)*

Thanks for the clarification on the low voltage indicator Bigmac! Yeah, that's I guess what I do with my M40C, if I'm using low or medium for an extended period and I'm getting concerned, I just flip it to high for a few seconds to see if the indicator lights up and if it doesn't, then I'm good for a little while longer. This way, you get the earliest possible warning so you don't discharge so deeply. I usually like to recharge anywhere between 3.6 and 4.0 preferably nearer the latter. Is this good practice? I guess not much difference between 3.6 and 3.3 as after 3.6 it's empty and drops quickly. Just want my batteries to last and not to make them too angry/unstable.


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## Bigmac_79 (Dec 20, 2011)

*Re: Object/Subject Review: Sunwayman T20CS (In Progress)*

You're right that you can use the higher modes to get an earlier low battery warning, I've found myself doing that with the T20CS.

I'm not a battery expert, but from my understanding, discharging your li-ion to the point where the protection kicks in won't hurt it, and you're more likely to decrease the lifetime of your cell by over-charging it. I've heard a lot of people say they like to only charge their li-ions to 4.15 or 4.16 V (if they have a charger they can do that with) as it makes them last longer. I imagine if you're only using the cell from 4.15 or 4.2 V down to 4.0 V you're not getting a lot of runtime, and maybe decreasing the lifetime of your cell by charging it more often than necessary.

Again, though, I don't know a ton about batteries, so someone else might be able to answer your question better. I'll just say that you should be fine waiting until the indicator comes on before you change cells.


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## Bigmac_79 (Dec 21, 2011)

*Re: Object/Subject Review: Sunwayman T20CS (In Progress)*

Alright, I've added a ton of pictures and information, and a couple of videos. The only thing left is to do the beam shots, then I'll move on to the subjective review. It looks like we'll finally get a clear night tonight, so this might be my chance.


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## MrLi (Dec 21, 2011)

*Re: Object/Subject Review: Sunwayman T20CS (In Progress)*

Thank you, Bigmac_79, for the video on the interface. It clears up my confusion. Though, the interface looks busy, but I haven't tried it out myself yet so I can't make any judgement.


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## zs&tas (Dec 21, 2011)

*Re: Object/Subject Review: Sunwayman T20CS (In Progress)*

great review ! reminds me of a surefire Z2 on steriods, nice ! do you only have trustfire 18650, i need some not sure what to buy, are you happy with there performance in a high output light like this ?


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## peterharvey73 (Dec 21, 2011)

*Re: Object/Subject Review: Sunwayman T20CS (In Progress)*

Great reviews BigMac.
On a V10R or V20C XM-L's, the amperage is low; around 1.5 amps or even less.
On this T20CS with 658 lumens, the amperage is high; or close to 3 amps.
The electronic circuit will add to the amperage too.
Do you notice any flickering, or your Trustfires and XxxFires playing up?
Coz it played up on my SC600 with 750 lumens OTF.
Do you have any reputable AW or Redilast 2900/3100 mAH batteries to test? Because they may give you greater output too.
Callieskustoms are also high quality Panasonic cells, with aftermarket protection circuits added, but at a cheaper price than the others...


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## Helmut.G (Dec 21, 2011)

*Re: Object/Subject Review: Sunwayman T20CS (In Progress)*

On the matter of batteries:


Every battery, not only Li-Ion, has got an *internal resistance*. Generally good and new batteries have a low IR, and it increases with age (and low temperature). Cheap batteries often have a high IR.

A battery with a high IR can have a good performance when you don't need a lot of power, but if you need a lot of power, it will suck.

Example: Alkaline batteries power your clocks just fine for years and years, but in a high power LED light they will only last a very short time. The energy is right there in them, but it can't be extracted fast enough because their IR is way higher compared to eg eneloops or energizer lithium.
Btw: Zinc-Carbon batteries are even worse than alkalines in this regard (by far, actually). Don't ever ever buy cheap batteries that don't say alkaline on them or the packaging. They are not worth it. They don't have a single advantage and they are much more prone to leakage, too.
Another example with extremely much stored energy but no available power are SAFT batteries.


In a light like this you need batteries with a low IR.



You might wonder why am I writing this? Because IR is the key to understanding what I'm gonna say about the low-battery warning.

When you run your light, a current is drawn from the battery. The battery's voltage sags according to Ohm's law.
Ohm's law says V=R*I, that is _Voltage equals Resistance times Current_.
So, if you double the current, the voltage sag will double. *Voltage sag is proportional to current draw (and internal resistance).*

Example: Your battery is a 18650 Li-Ion with an IR of 0.2 Ohm and a voltage of 4.2 V when fully charged.
You draw 1 Ampere from the battery. The voltage sag is 1A * 0.2Ω=0.2V . In this example the battery's voltage under load will be 4.2 V - 0.2 V = 4.0 V.

A battery's voltage under load is basically resting voltage (what you measure when you take it out of the light) minus voltage sag.
Voltage sag is proportional to current draw and IR. IR also varies with the battery's charging state, btw. (If you read this, you probably already guessed it, there are a lot of factors that determine IR of a particular battery. But we don't really need to care about them here. All we need to know: Good batteries will have a lower IR than junk like most of the ****fire stuff.)
So, *the more current draw, the lower the voltage under load is.*

With this knowledge we're nearly there :sweat:


*[Everything below is specific to Li-Ion]*


Now we need to know what a protection circuit does. 

It's very simple: It measures the voltage of the battery. The real under-load voltage.
If this voltage reaches a pre-determined threshold (can be different depending on the circuit) the battery is shut off.
The threshold is set to a voltage that is noticably lower than any healty resting voltage for a Li-Ion battery.
But since in actual use there is battery sag, the resting voltage will stay in the healthy area _if the current (and thus the difference between voltage under load and resting voltage) is big enough._

Examples (NOTE: not necessarily realistic numbers, I made them up for this example only, but they might be close to reality):
The threshold could be 2.5 V and the Voltage sag 1V (big current). When the protection kicks in, the battery will have a no-load resting voltage of 3.5 V. (And maybe rising a bit if you let it sit some minutes).
With the same battery, at a lower current the Voltage sag could be 0.2 V (small current). When the protection kicks in, the battery will have a resting voltage of 2.7 V.
Now if we compare these examples, in the first case the battery is at 3.5 V. That's completely empty but not damaged.
In the second case, we have the very same battery, in the very same light, but used in a low level until the protection kicked in.
A resting Voltage of 2.7 V is way too low. This battery is completely dead. It needs to be disposed off. The protection didn't protect it.


This is all we need to know to evaluate this statement:


> discharging your li-ion to the point where the protection kicks in won't hurt it


_Short answer: true on high power settings, very wrong on low power settings._

If you run your light in turbo, voltage sag will be so big that there might even be some useable energy left in the cell when the protection kicks in.
If you run your battery into protection in moonlight mode, there's not only no energy left, but the cell was virtually tortured to death slowly.




*And now to what I think about the battery warning feature implemented into the light in question:*

*Bigmac, if your voltage readings are correct, and I understand your text correctly and my knowledge about batteries (and what I wrote above) is correct, then the low battery warning in this light is implemented completely wrong in order to save LiIon batteries.*

In the lower modes the warning only comes on at lower battery voltages. It would need to be the other way around. See my moster text above if you want to know why.
In my opinion the values are way too low in Med and Low.

*I would recommend to only rely on this warning function in Turbo and High mode if you want your expensive 18650 to last. Exceptions are the new chemistries that are said to be able to survive discharging to incredibly low voltage levels (compared to other similar Li-Ion).
Don't run your batteries down until the light starts flashing in Med and Low.*


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## Bigmac_79 (Dec 21, 2011)

*Re: Object/Subject Review: Sunwayman T20CS (In Progress)*



MrLi said:


> Thank you, Bigmac_79, for the video on the interface. It clears up my confusion. Though, the interface looks busy, but I haven't tried it out myself yet so I can't make any judgement.



You're welcome :thumbsup:

I'll elaborate on my opinion as I finish the review, but basically, while I think the UI isn't as simple as I would like, it works well as a tactical interface.



zs&tas said:


> great review ! reminds me of a surefire Z2 on steriods, nice ! do you only have trustfire 18650, i need some not sure what to buy, are you happy with there performance in a high output light like this ?



The only 18650 cells I have right now are the Trustfire Flames 2400 mAh from DX. For the price I paid for them, I am very happy  I would love to have some higher quality cells that could perform better in high output lights like this, but that's just not in the budget right now. If you can afford it, I would recommend something better quality, but if not, these will get the job done.



peterharvey73 said:


> Great reviews BigMac.
> On a V10R or V20C XM-L's, the amperage is low; around 1.5 amps or even less.
> On this T20CS with 658 lumens, the amperage is high; or close to 3 amps.
> The electronic circuit will add to the amperage too.
> ...



I've not noticed any flickering with any cells, or any other problems with the performance. I just believe that highe quality batteries will be able to sustain higher outputs for longer periods of time. I've seen a little info on Callieskustoms cells, I need to check out the pricing on those.



Helmut.G said:


> On the matter of batteries:
> ...
> ...
> ...



Thanks for sharing your knowledge of batteries! As far as I know, all the facts you've shared are true. On the higher modes, there will be more voltage sag (and I have definitely observed that in my tests, the voltage measured across the battery rises quickly after I turn off the light), and on the lower modes, there will be less. However, I'm not prepared to agree with your final assertion until I've looked into the specifics a little more. Your example makes sense, but the actual numbers are what's important, so we can't afford to guess. I'll do some research. What I need to find out is: the voltage it is "safe" to discharge a li-ion cell to, the voltage that is "healthy" for the cell to discharge to, and just how much the current sags on the lower modes. 

Here's why. The voltage sag acts as a buffer for the protection circuit. The low voltage indicator on the T20CS sees the same sagged voltage as the protection circuit sees, so the "real" (resting) voltage of the cell will always be at least slightly higher than the voltage under load, and slightly higher than what the protection circuit and low voltage indicator see. This means that as long as the protection circuit is set to cutoff at a high enough voltage (greater than the healthy discharge voltage for the cell) then there won't be any problems.

For example, if it is safe to discharge a cell to 2.75 volts, and the protection kicks in at 2.8 under load, the resting voltage will actually be higher than 2.8, which is also higher than 2.75.

And anyway, if it isn't safe to run a cell down to the voltage where the protection kicks in, even under very small loads with little voltage sag, then that seems to me to be a problem with the voltage the protection circuit is set to, not the low voltage indicator on the T20CS.

I'll look into it more, but according to this page: http://www.candlepowerforums.com/vb/showthread.php?308451, it looks like for many brands of cells, there is still a small amount of usable capacity below 3V, which is about where I measure the T20CS's low voltage indicator to come on when in low mode.


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## Lou Maan (Dec 22, 2011)

*Re: Object/Subject Review: Sunwayman T20CS (In Progress)*

I sense you will be getting many free lights in the future if you keep up these excellent reviews. Bigmac, that is either one very small light or you really live up to your name with massive hands. Usually we'll call someone who is big: "Tiny Tim" or something. I don't know. What do I care. Just an observation.


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## Lou Maan (Dec 22, 2011)

*Re: Object/Subject Review: Sunwayman T20CS (In Progress)*

BTW... who would like Sunwayman to make a tactical bezel on this tactical light? Say "I".


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## Bigmac_79 (Dec 22, 2011)

*Re: Object/Subject Review: Sunwayman T20CS (In Progress)*

My hands are definitely largely than average, so you can take that into consideration when you look at the photos, but this light really is a lot smaller than I expected it to be. 

I also think a crenelated bezel would work very well on this light, it could be designed to match the pattern of the grooves on the head, and it would look extremely good.


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## robusmcs13 (Dec 22, 2011)

*Re: Object/Subject Review: Sunwayman T20CS (In Progress)*

Great review, Thanks!


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## Helmut.G (Dec 22, 2011)

*Re: Object/Subject Review: Sunwayman T20CS (In Progress)*



Bigmac_79 said:


> [...] but the actual numbers are what's important, so we can't afford to guess. [...]


Agreed.

Here's a small quote from AW's battery sales thread, there are numbers on how much energy is available at certain voltages and advice on how to treat LiIon batteries:


AW said:


> [...] Please keep the voltage of all LiIon batteries above 3.8V for healthy storage. Recharge as soon as possible when you have run them down. Storing a depleted ( less than 3.6V open voltage ) battery may damage/ shorten life/cycle permanently.
> 
> 
> LiIon Battery Charge Status
> ...


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## peterharvey73 (Dec 22, 2011)

*Re: Object/Subject Review: Sunwayman T20CS (In Progress)*

BigMac, I noticed you added some nice photos.
With a 38mm bezel diameter, the T20CS is still a tad relatively small-medium in size rather than a true medium size like an RRT-1 or RRT-15 with a 48mm bezel diameter, however all that is relative only.

BM, did you notice that your current draw was:
1.55 amps on 2xCR123 Energizers,
0.998 amps on 2x16340 Ultrafires,
1.96 amps on 1x18650 Trustfire?

Helmut was saying something similar about how the cheaper low quality batteries have more internal resistance, thus a slower discharge rate, hence a lower amperage, which generally means less lumens too.
Notice how the Ultrafire 16340's are only drawing 0.998 amps on turbo?

In general, the bigger 18650 will have lower internal resistance, and a faster discharge rate, with a higher amperage, than a 16340.
Thus 1.96 amps on the 18650 versus just 0.998 amps on the 2x16340 Ultrafires.

Rechargeables tend to have a lower internal resistance and faster discharge rate with higher amperage than disposable batteries.
Here, at 0.998 amps, the Ultrafire 16340's may be underperforming relative to the Energizer 2xCR123's?
However, we can try an AW 16340 750 mAH Protected from AW himself:
http://www.cpfmarketplace.com/mp/showthread.php?230876-AW-s-LiIon-Batteries-Sales-Thread-*Part-12*
He is very reliable; I live in Australia, and I normally receive them in 8 working days, in a nice plastic 2x18650/4x16340 container too!
The AW's are used as a benchmark by Selfbuilt etc.

BM, with the lower current draws on turbo mode, do you notice less lumen output too?
Because when I used Ultrafire 18650 2400 mAH Protected on my SC600, it was _less bright_ than when I used quality Redilast 3100 mAH Button Tops.
The quality Panasonic cells with aftermarket Jap IC Protection circuits have lower internal resistance, and so deliver a higher amperage to my hungry SC600 with 750 lumens OTF, than my Ultrafire 18650's...


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## Grizzlyb (Dec 22, 2011)

*Re: Object/Subject Review: Sunwayman T20CS (In Progress)*

Bigmac,

Thanks for the clear review. Sunwayman seems to be on target with this one. 
1 point I dislike, there is no way to set the strobe in memory. 
From my point of view, that is a reason we can't use this light for our work.
I look forward to the subjective Review thou, specialy the Tactical part.


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## Rokron (Dec 22, 2011)

*Re: Object/Subject Review: Sunwayman T20CS (In Progress)*

I! 


Lou Maan said:


> BTW... who would like Sunwayman to make a tactical bezel on this tactical light? Say "I".


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## zs&tas (Dec 22, 2011)

*Re: Object/Subject Review: Sunwayman T20CS (In Progress)*



Bigmac_79 said:


> The only 18650 cells I have right now are the Trustfire Flames 2400 mAh from DX. For the price I paid for them, I am very happy  I would love to have some higher quality cells that could perform better in high output lights like this, but that's just not in the budget right now. If you can afford it, I would recommend something better quality, but if not, these will get the job done.
> 
> 
> 
> .



ok thanks, just got my first 18650 light got some cheaper ultrafire 3100 for now just so i have avaliable juice, ill prolly get an aw2900 in a few months. 

im liking the flat bezel ! wish my scorpion had one ..


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## Helmut.G (Dec 22, 2011)

*Re: Object/Subject Review: Sunwayman T20CS (In Progress)*



peterharvey73 said:


> [...]1.96 amps on the 18650 versus just 0.998 amps on the 2x16340 Ultrafires. [...]


It's actually completely normal for a regulated light like this to draw less current at a higher voltage.
Since 2x16340 have two times the voltage of 1x18650, the input power stays the same while current halves. The output power to the LED should also stay at roughly the same value, but most drivers have a different efficiency at different input voltages.
In order to judge the quality of the ultrafire 16340s you would need to compare them to other 16340-sized batteries to be able to draw any useful conclusions.


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## RCLumens (Dec 22, 2011)

*Re: Object/Subject Review: Sunwayman T20CS (In Progress)*

Bigmac, I agree - with these kinds of reviews, I hope you get plenty of lights sent your way. I hope the manufacturers realize what a value these are and not to mention, it benefits them hugely. I'm anxious to see the bra shots and to hear your impressions after all the data is gathered. As for the batteries, I think it's actually an advantage to test using standard batteries as this plays in part to most real world applications. At least speaking for myself, I have some AW's set aside for stand-bys as most of my applications grant me access to recharging daily. 

Thus far it seems like the light is holding up rather well. Ui could probably be easier, but it doesn't sound like it's a hinderance either. It does look small in the pics and based on your impressions, so I'm curious on the throw numbers and pics. Awesome review and very helpful! Any chance you have a tk21 to compare it to? Also, do you know anyone who can do a thorough review of an RRT3 triple XML? Cheers and many thanks!


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## Lou Maan (Dec 22, 2011)

*Re: Object/Subject Review: Sunwayman T20CS (In Progress)*



zs&tas said:


> ok thanks, just got my first 18650 light got some cheaper ultrafire 3100 for now just so i have avaliable juice, ill prolly get an aw2900 in a few months.
> 
> im liking the flat bezel ! wish my scorpion had one ..


Look that's fair enough. It doesn't chew up the inside of your pocket. But I like the fact that with my V20C, I have the option. Most people don't know that there is the same one available on V20C as with the T20C. Btw, that is the best (most pain inflicting) bezel I have ever worn on any flashlight. That's okay, when I go out with my flat bezel T20CS, I'll just carry something else in my other pocket for protection. Just means I have to carry 2 things. 3.5x more cd power is worth it I guess (as long as the hot spot isn't too small) although the V20C does a good job.

@ Bigmac. Did you know you can turn it on from the side switch straight to high even though your last programmed memory might be low or medium? Yep, just hold down the side switch and you have a slightly delayed but still convenient high if you're in a pinch. Great photos and videos btw.


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## Bigmac_79 (Dec 23, 2011)

*Re: Object/Subject Review: Sunwayman T20CS (In Progress)*



Helmut.G said:


> Agreed.
> 
> Here's a small quote from AW's battery sales thread, there are numbers on how much energy is available at certain voltages and advice on how to treat LiIon batteries:



Thanks for those numbers, that's very helpful! That's consistent with the data I have found in my research as well. It looks like on the two top 18650 brands on CPFMP (AW and Redilast), their capacity is listed from 4.2V to 2.8V or 2.5V. AW protection circuits seem to be set to 2.2V and Redilast to 2.5V or 2.45V. From what I can tell, discharging your cell down to the protection circuit is acceptable, but you don't want to do it really often, and you definitely don't want to store your cell at the voltage. The danger to relying on the protection circuit seems to be not that the voltage cutoff is too low for the cells, but that on low currents, sometimes you can slip past the voltage the protection circuit without activating it, taking your cell down to levels waaaayyy too low (or sometimes the protection circuit can get damaged without your realizing it). So, if you do let your cell get down to 2.5 or 2.8V, using the full capacity, you want to make sure you recharge it right away, and don't let it sit in that condition. 

Luckily for us, the T20CS has the low voltage indicator, which comes on at least by the time the cell hits 3V. So, for now I'm going to recommend that for optimal cell health, you should be recharging your 18650's before the low voltage indicator comes on when you can, but it won't hurt your cells to wait until the indicator warns you. And in general, with whatever light you use, don't rely too heavily on the protection circuits of your protected cells.

After this, I'll agree that I would prefer the low voltage indicator to be set a little higher, so that you don't unknowingly store your cells at a voltage lower than 3.8V. I can see myself running the battery down to 3.5V and then turning the light off when I'm done with it, and storing it that way for a while without realizing the voltage was so low. Ideally, the low voltage indicator could come on solid around 3.7V or 3.8V to let you know it's time to recharge before storage, and then start flashing around 2.8V or 2.9V to let you know you're reaching the end of the battery's capacity.

Thanks for your helping in working this out!



peterharvey73 said:


> BigMac, I noticed you added some nice photos.
> With a 38mm bezel diameter, the T20CS is still a tad relatively small-medium in size rather than a true medium size like an RRT-1 or RRT-15 with a 48mm bezel diameter, however all that is relative only.
> 
> BM, did you notice that your current draw was:
> ...



I agree on your opinion of the size, I would call this slightly smaller than a "medium" sized light 

It's true that higher quality betters have lower internal resistance, and are thus able to provide higher currents. However, I did expect the current draw on 2x18650 to be the highest, then 2xCR123, then 1x18650, because of the voltage difference. At higher voltages, the driver doesn't need as much current from the batteries in order to supply the correct current to the LED. I did some interesting measurements yesterday that I haven't posted yet. As you'll notice, the measurements I already posted were done at the tail cap, but I discovered I can also do measurements at the emitter, and when I do, I find the voltage applied to the LED (and thus the current flowing through it) to be the nearly identical across both 2x16340 and 1x18650 on all modes, even turbo. 

You'll also notice on the output graphs that each battery starts with very nearly the same output on Turbo (close enough to chock up the differences to instrument error if you want). My opinion is that higher quality batteries will be able to sustain those currents better for longer periods of time, but at the beginning, both my lions are right up there with the energizer CR123 primaries.

I would love to have some name-brand lions, but at this time I really don't have the money for them. I'm taking volunteers that want to donate some for the advancement of science 



Grizzlyb said:


> Bigmac,
> 
> Thanks for the clear review. Sunwayman seems to be on target with this one.
> 1 point I dislike, there is no way to set the strobe in memory.
> ...



You're welcome 

It's true that the strobe doesn't get set in memory. However, in practice the strobe is actually quicker to get to than, say, low mode. Once you have the T20CS in "standby" (by turning it on by the tail cap, then off with the side switch), you can go directly into strobe by a double-click on the side at any time. This way, you never have to cycle through modes when you need strobe quickly, and it doesn't get in your way when you don't want it. To me, this seems a better setup than having strobe in the regular lineup of modes, whether you use it often or not. 

Just curious, what work is it that you do, and what do you look for in a "tactical" interface on a light for your work?


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## Bigmac_79 (Dec 23, 2011)

*Re: Object/Subject Review: Sunwayman T20CS (In Progress)*



Helmut.G said:


> It's actually completely normal for a regulated light like this to draw less current at a higher voltage.
> Since 2x16340 have two times the voltage of 1x18650, the input power stays the same while current halves. The output power to the LED should also stay at roughly the same value, but most drivers have a different efficiency at different input voltages.
> In order to judge the quality of the ultrafire 16340s you would need to compare them to other 16340-sized batteries to be able to draw any useful conclusions.



Yep, that's my understanding as well. While the LED is output is determined by current, the driver supplies current to the LED based on the power it receives, which is voltage x current. So as long as the battery can supply enough current to make up for lowering voltage, the driver can supply a constant current



RCLumens said:


> Bigmac, I agree - with these kinds of reviews, I hope you get plenty of lights sent your way. I hope the manufacturers realize what a value these are and not to mention, it benefits them hugely. *I'm anxious to see the bra shots* and to hear your impressions after all the data is gathered. As for the batteries, I think it's actually an advantage to test using standard batteries as this plays in part to most real world applications. At least speaking for myself, I have some AW's set aside for stand-bys as most of my applications grant me access to recharging daily.
> 
> Thus far it seems like the light is holding up rather well. Ui could probably be easier, but it doesn't sound like it's a hinderance either. It does look small in the pics and based on your impressions, so I'm curious on the throw numbers and pics. Awesome review and very helpful! Any chance you have a tk21 to compare it to? Also, do you know anyone who can do a thorough review of an RRT3 triple XML? Cheers and many thanks!



There'll be no bra shots, I'm a happily married man :nana: 

But seriously, I'm looking forward to doing the beam shots as well.

No, I don't have a TK21 or RRT3 to compare this to, but, just like the name brand batteries, I wouldn't turn down a donation for the advancement of science 




Lou Maan said:


> @ Bigmac. Did you know you can turn it on from the side switch straight to high even though your last programmed memory might be low or medium? Yep, just hold down the side switch and you have a slightly delayed but still convenient high if you're in a pinch. Great photos and videos btw.



I hadn't discovered/noticed that, thanks!


----------



## peterharvey73 (Dec 23, 2011)

*Re: Object/Subject Review: Sunwayman T20CS (In Progress)*



Helmut.G said:


> It's actually completely normal for a regulated light like this to draw less current at a higher voltage.
> Since 2x16340 have two times the voltage of 1x18650, the input power stays the same while current halves. The output power to the LED should also stay at roughly the same value, but most drivers have a different efficiency at different input voltages.
> In order to judge the quality of the ultrafire 16340s you would need to compare them to other 16340-sized batteries to be able to draw any useful conclusions.



Thanks for pointing that out Helmut; we learn something new everyday.
You're right. I did not take into account that with two batteries, in series, the voltage adds together.
P=VI
Power (watts) = Voltage (volts) x Current (amps)
Power can neither be created, nor destroyed; however, power can be lost by friction or heat etc.
So, with 2xCR123's, the voltage goes up to 6 volts, so the current must go down, to maintain the overall power.
With 2x16340's, the voltage goes up to 7.4 volts etc, so the current must go down a long way, to maintain the overall power.
Thus, like you say, we can only compare the current/amperage from the twin 16340 Ultrafires, to another pair of 16340 batteries.

PS.
Actually Helmut, I'm now a bit confused?
Perhaps you could help me.
The reason why a V10R XM-L U2 bin has 160 lumens on a 3.0 volt 1xCR123, but 500 lumens on a 3.7 volt 16340, is because the voltage rises, but the current is maintained or even increased, so there is actually more power in Watts when using the 16340's?
It's complicated - I'm confused...


----------



## Lou Maan (Dec 24, 2011)

*Re: Object/Subject Review: Sunwayman T20CS (In Progress)*



peterharvey73 said:


> PS.
> Actually Helmut, I'm now a bit confused?
> Perhaps you could help me.
> The reason why a V10R XM-L U2 bin has 160 lumens on a 3.0 volt 1xCR123, but 500 lumens on a 3.7 volt 16340, is because the voltage rises, but the current is maintained or even increased, so there is actually more power in Watts when using the 16340's?
> It's complicated - I'm confused...



Ok, I know nothing but here's what I'm thinking and I tried starting a thread about that without too many good answers. There must be a certain voltage (maybe 3.6 volts I don't know) where circuitry on the Ti2 says: "okay! we're dealing with a 16340 here, let's suck all the voltage AND amps we can out of this battery, but no more than we need to get us to 500 lumens." If it wasn't limited to 500, I could stick AW IMR's which do 8C and I'd get 900 lumens, who's with me?

I hope someone can answer that but anyway, all I can say is the Ti2 is visibly brighter on Trustifre 16340 than the 460 lumen regular V10R. It's only 60 lumens difference so I shouldn't be able to tell visually but it seems to be able to draw a lot more power out of the same battery. Another thing I noticed is that my M10A on a 14500 doesn't do all that well on high but with strobe, it's like it's probably hitting the 460 mark. Probably because strobe takes half the power that high does so it can produce the lumens. Anyway, just answering a question but I'm probably on a tangent. But i believe the topic of batteries have everything to do with the light itself so you can't keep them seperate. No battery, no light. This is a good thread.


----------



## peterharvey73 (Dec 24, 2011)

*Re: Object/Subject Review: Sunwayman T20CS (In Progress)*

You have a good idea Lou Maan; perhaps it works like that...


----------



## Bigmac_79 (Dec 24, 2011)

*Re: Object/Subject Review: Sunwayman T20CS (In Progress)*

"General" and "Tactical" sections of the subjective review complete!


----------



## candle lamp (Dec 25, 2011)

*Re: Object/Subject Review: Sunwayman T20CS (In Progress)*

Very well done. Bigmac79!
Thanks for your very nice review and effort. :thumbsup:
It looks very good & well-made light.
It's just a shame that the performance on 1x18650 is not better than I expect. Assume it's because of the wide working voltage(2.5~10V).

P.S : But T40CS shows the flat regulation with 18650's in spite of 5.5~16.8V working range. :shrug:.

Thanks again for the review.


----------



## Helmut.G (Dec 25, 2011)

*Re: Object/Subject Review: Sunwayman T20CS (In Progress)*



Lou Maan said:


> Ok, I know nothing but here's what I'm thinking and I tried starting a thread about that without too many good answers. There must be a certain voltage (maybe 3.6 volts I don't know) where circuitry on the Ti2 says: "okay! we're dealing with a 16340 here, let's suck all the voltage AND amps we can out of this battery, but no more than we need to get us to 500 lumens." If it wasn't limited to 500, I could stick AW IMR's which do 8C and I'd get 900 lumens, who's with me?


It's quite simple:

The circuit in 1xCR123 lights (and in 1xAAA, 1xAA, 2xAA) needs to increase the voltage it gets from the battery.
This is called boosting.
There are also buck-circuits, lowering the input voltage (e.g. in 2xCR123 or 3xCR123 lights).

This is needed because white LEDs need a certain voltage to shine brightly, and this voltage is (depending on the LED type, individual LED and desired current through it) slightly to very significantly higher than the battery's voltage under load.

Now LiIon batteries have higher voltages, and _a fully charged LiIon will exceed the voltage needed to power up most LEDs _used in Flashlights.
There are LED drivers in flashlights that can both step up and step down the input voltage, but they are very rare.

Most boost circuits simply let the LED run directly from the battery (or batteries) once the battery's voltage under load reaches the needed LED voltage for the desired output level.

Now you need to know that LEDs will increase their current very fast as you give them more voltage.

Here's an example from jtr1962's most excellent LED lumen testing thread:
A Cree XP-G tested needed 3.01 V to run at 0.350 A.
At 3.50 V, only at 16% increase the LED ran at 2.5 A (a 714% increase).

Note that every single LED will vary here! If you buy two XP-Gs or XM-Ls they will not have the very same current vs voltage curve.

Now you see that XP-Gs have a pretty low Vf (forward voltage) compared to the 4.2 V of a Lithium Ion, and XM-Ls are similar.

_The only thing that protects these LEDs from burning out when you use them with an RCR123 in this way is the internal resistance of the battery._
If you'd connect the LED to a lab power source than can sustain high currents and hold the voltage at 4.2 V, instant  would be the result.


So, Lou Maan, if you run your light with an IMR battery you should indeed get more current through the LED because the IMR has a lower internal resistance.
Be aware that the higher you push the current, the smaller the resulting difference in output gets so it might not be worth it.
At some point (that is determined by the LED type and the heatsinking) the LED will even produce less light if you raise the current further.
If you are interested in this look into the Lumen testing thread linked above.

Btw the more extreme currents you use the greater the difference between LED lumen output bins gets. While a T6 binned and a U2 binned XM-L will be extremely close in output at low and standard currents, if you push them to the max the difference could become significant because less heat produced (and the higher bin will produce less heat) means lower LED temperature and thus higher efficiency.


Not all LEDs are created equal. If you go into extreme territory the differences will show.


Lou Maan, is your V10R Ti equipped with an XP-G? The XM-L has a lower Vf so it should run noticeably brighter in direct drive with an RCR123.


----------



## Lou Maan (Dec 25, 2011)

*Re: Object/Subject Review: Sunwayman T20CS (In Progress)*



Helmut.G said:


> It's quite simple:
> 
> The circuit in 1xCR123 lights (and in 1xAAA, 1xAA, 2xAA) needs to increase the voltage it gets from the battery.
> This is called boosting.
> ...


Very interesting! Thanks that's a lot to take in but that's why I'm here . I have the V10R (T6) and the V10R Ti2 (U2), and there's just such a huge difference using even the same battery. (I know because I have two RCR's and when I swap, the U2 is still so much brighter.) It's not just a dud T6 either, I have 3 of the T6 ones 2 U2's and the story is the same right across.


----------



## Lou Minescence (Dec 26, 2011)

*Re: Object/Subject Review: Sunwayman T20CS (In Progress)*

Great job Bigmac. Very informative and presented well. Selfbuilt may have some competition. I was looking for some vocal narration on the you tube video. Just a thought. Thank You.


----------



## Bigmac_79 (Dec 26, 2011)

*Re: Object/Subject Review: Sunwayman T20CS (In Progress)*



Lou Minescence said:


> Great job Bigmac. Very informative and presented well. Selfbuilt may have some competition. I was looking for some vocal narration on the you tube video. Just a thought. Thank You.



Thanks for the encouragement and the advice!


----------



## Bigmac_79 (Dec 26, 2011)

*Re: Object/Subject Review: Sunwayman T20CS (In Progress)*

Outdoor beamshots added! Very impressive throw, lit up a silo at ~1/3 mile.


----------



## Bigmac_79 (Dec 27, 2011)

*Re: Object/Subject Review: Sunwayman T20CS (In Progress)*

Alrighty, white wall beam shots added and "Thrower" subjective review added. 

This review is complete, with long term impressions pending!

:thumbsup:


----------



## RCLumens (Dec 27, 2011)

*Re: Object/Subject Review: Sunwayman T20CS (In Progress)*

Excellent review BigMac - through & through (even though the light threw) haha - sorry just a bit of scotch talking after some guests departed... Great review and is very useful! So the throw certainly seems worthy, especially given the size. I wish I had the resources to do a comparison between this and the TK21 - perhaps I will - but I think I'm going to pick up a t20cs in January regardless. Tough to beat this throw in a package so small. Any longer term impressions are always welcomed!! Cheers and Happy New Year to all! Excellent review BigMac!


----------



## phantom23 (Dec 27, 2011)

*Re: Object/Subject Review: Sunwayman T20CS (In Progress)*



candle lamp said:


> It's just a shame that the performance on 1x18650 is not better than I expect. Assume it's because of the wide working voltage(2.5~10V).
> 
> P.S : But T40CS shows the flat regulation with 18650's in spite of 5.5~16.8V working range. :shrug:.


Wide voltage range doesn't mean it has to be unregulated. It seems that T20CS driver has a huge dropout voltage (difference between the input voltage and output voltage to remain constant output current), even AMC7135 is better. Most producers try to reduce it but obviously Sunwayman has decided to optimize T20CS to 2xCR123A. Weird thing it - they failed...

T40CS uses 2x18650, that's 8,4V when fully charged and 5,5-6V when discharged.


----------



## Lou Maan (Dec 27, 2011)

*Re: Object/Subject Review: Sunwayman T20CS (In Progress)*



Bigmac_79 said:


> Alrighty, white wall beam shots added and "Thrower" subjective review added.
> 
> This review is complete, with long term impressions pending!
> 
> :thumbsup:


Good stuff Bigmac! Well done and as objective as possible whilst still giving us some feedback to work with . Sounds like it throws well enough and the smaller head means more pocketability. In a defensive situation, that would be tons more than enough to keep the assailant at a distance and at least the hotspot isn't so small that you can only aim it precisely in one eye at a time . Ouch! 

That silo being 1/3 mile away, that's about 586 yards! And don't forget the light that hits the object has to make it back to your eye for you to perceive it. So that light has traveled 1172 yards and probably far beyond. I'd say that classifies as a thrower, yes indeedeedoo.


----------



## Lou Maan (Jan 7, 2012)

*Re: Object/Subject Review: Sunwayman T20CS (In Progress)*

@ Bigmac

What I am posting today really sucks and I think there may be a major recall on these lights. I've just started a thread on this problem but I thought you (and Sunwayman) should be the first to know since I know you have one too. Anyway, let me know how you go please. I can't believe no one else has noticed this yet but now a buddy a mine says his light does exactly what mine does... anyway, here's how the post goes:

Hi, got my T20CS this week and everything seemed to work fine at first. Then one night I decided to pretend I was in a real life tactical situation and double clicked for strobe. After about 5 seconds the light turned itself off. I was like: "What the? Did that just happen?" Clicked it once more and it returned to strobe for half a second then went off again. Everything was tight, tested my battery and it was good, changed the battery today and it's doing it consistently except it goes to low after. I have good batteries and the strobe is only on high, it's not like it's a turbo strobe so the batteries can sure handle a sub 500 lumen strobe. Just glad I tested it before trusting my life to it. Okay, maybe I'm jumping the gun here but is there something I need to clean, is it just a dud, or should I be using something else as a tactical light because side switch electronics just do that (malfunction)?

Just for reference, my T40CS malfunctions too but only when I'm on low, I go to switch it off with a single click and strobe kicks in. I'm not riding the switch with my finger or anything, it's clearly off, I know how to properly/cleanly click buttons, been using buttons all my life on computer/Nintendo/X Box whatever so I really do think there is a problem with this configuration. The only thing that's never let me down is my T20C which has a completely different switch system (and a nice strike bezel I might add. Is anyone else experiencing this problem or is it just me? Can I do something to fix it?

Addition: It only happens if I depress the rear switch and turn it off, then turn it back on again via the rear switch (ie fresh start) then program it to low, turn it off from the side switch, then turn the strobe on from the off by double clicking. Then it turns itself off after a 5 second strobe. Alternatively, if I leave it on turbo then turn it off on the side, if I double click from that off position, there is strobe for 5 seconds and returns to high or turbo (hard to tell). Hard to explain because of the UI is complex but I hope some guys get what I mean and try it to see if it happens to them. Thanks.


----------



## Mikellen (Jan 7, 2012)

*Re: Object/Subject Review: Sunwayman T20CS (In Progress)*

One question... When the flashlight tail switch is in the off positon, and the batteries are low, will the red led low battery indicator start to blink? If so then that would not be very good in a tactical situation when it is important for an LEO's position not to be given away. 

Example: If the batteries were not as fresh as they should be and a LEO (law enforcement officer) is conducting a building search for suspects. In this case the LEO would most likely only use short momentary bursts of light in order to reduce his or her position from being noticed. The LEO does not want the light on for any length of time or anything else that could give their position away to the suspect(s). So if the low battery indicator starts to activate (indicating low battery) then that could place the LEO in a compromising position. 

Is there an option to disengage the low battery indicator? If not then in my opinion the LEO would have to be sure that the batteries have enough stored energy in order to avoid the LBI's blinking light from coming on and possibly jeopardising the LEO's safety. I personally have conductd many of these types of searches and would not use a light that has a low battery indicator. My thought is, even if the batteries were fresh its possible that the LBI can malfunction for whatever reason and start to activate.

Edit: If the LBI can only activate when the flashlight is on and will immediately deactivate as soon as the tailcap switch is disengaged then my concerns above are alleviated some. I still would prefer not to have the LBI because I think that the more features that are incorporated in a device then the greater chance for reliability issues. (Just my 2 cents).


----------



## Lou Maan (Jan 7, 2012)

*Re: Object/Subject Review: Sunwayman T20CS (In Progress)*

Your LBI won't activate if your tailswitch is disengaged. In fact, it won't blink unless your light is on full stop.

ps. Who's Leo?


----------



## Mikellen (Jan 7, 2012)

*Re: Object/Subject Review: Sunwayman T20CS (In Progress)*

Thanks for clarifying the low battery indicator activation. 

LEO= Law Enforcement Officer.


----------



## RCLumens (Jan 7, 2012)

*Re: Object/Subject Review: Sunwayman T20CS (In Progress)*

This stinks... Did you run into the same on yours BigMac? I'm so close to getting the light, but this might be a deterrent. Thanks for the info though Lou, It would have bummed me out, or worse, had you not posted this. Definitely appreciated!


----------



## Lou Maan (Jan 7, 2012)

*Re: Object/Subject Review: Sunwayman T20CS (In Progress)*

You're welcome RCLumens. I can't say I'm as excited about this light as I was when I opened the box.


----------



## RCLumens (Jan 7, 2012)

*Re: Object/Subject Review: Sunwayman T20CS (In Progress)*

Sorry to hear that Lou... How's everything else functioning? Throw, etc...? I've got a thread on here looking for this sized light as I'm also looking at the scorpion with Turbo head, and quite actually perhaps a Sunwayman V60C - I know it's a bit bigger, but the form and weight are not too bad - and the light will throw well. Any comparisons to the T20CS with your other lights? Cheers, RC


----------



## Lou Maan (Jan 7, 2012)

*Re: Object/Subject Review: Sunwayman T20CS (In Progress)*

Yeah, RCLumens, everything else works as it should. I guess it's still usable, you just don't use strobe from the off position which is a downer (and a deal breaker for me, mine's going back to the dealer and there are going to be a lot of very annoyed dealers out there now). You can blind the bejesus out of someone with the tail clicky. It's about 3-4 times more throwy (brighter hotspot) than the T20C, which itself is a VERY capable light. The hotspot isn't too small which means it's not hard to aim at something/one. Cool green tint, no donuts. Usually small-headed lights that throw like this one have narrow spill but it actually has decently wide spill so Sunwayman have figured out how to do that with this particular reflector design. They could easily develop a moderate size triple using this design of reflector that throws like crazy. Best reflector shape I've seen for XM-L. So wider spill than V20C, T20C. Now the V60C is a highly underrated light. It's compact enough but heavy and if you don't have big hands, it can get a bit tiring but it's fine for an hour or so. (Sorry moderators I know this is a T20CS review but someone asked to compare so I think it's appropriate). The V60C has a beautiful wide spill (wider than T20CS) and the hotspot will absolutely waste the T20CS in a throw/bright hotspot competition. Batteries seem to last forever because there are 3. I've only charged mine once to try the charger in 2 months. You can also keep the batteries in there if you have a charger because you can test voltage directly from the tail contacts!! They're both nice camping lights, depends on how much power/size/distance you need. I can't wait to hear more feedback on the switch issue.

I have a Ultrafire U80 which throws incredibly and has a 44mm head. The little SWM T20CS which has a 36 head I think gives it a run for its money and possibly beats it in throw. Hard to tell but very close. The T20CS is more pocketable and less aggressive looking. I'm thinking SWM will want to fix this problem because it's a good light in all other respects.


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## RCLumens (Jan 8, 2012)

*Re: Object/Subject Review: Sunwayman T20CS (In Progress)*

Many thanks again Lou! Great information! I'm relatively close to the folks at battery junction, so I drive there to pick up my lights and am able to compare form factors as I usually make the trip in the morning amid don't really have the chance to do beam comparisons. I'll be comparing the t20cs and will check out the strobe function while there - that could also be a deal breaker for me also. I'll also be comparing it with the scorpion v2 and the v60c. Anyway, perhaps I'll open up another topic/thread as I apologize for taking this one somewhat off topic. However, the t20 cs is certainly a contender, and this thread has been most helpful. Thank you and thank you to all the members here. Rc


----------



## Rokron (Jan 8, 2012)

*Re: Object/Subject Review: Sunwayman T20CS (In Progress)*

I've had my T20CS for 2 weeks now and I use it all the time including the strobe, the light works flawlessly. But after reading about the problem, I duplicated the same thing with my light. 
Myself, I don't concider it a problem, the light works per the instructions. Who knows, this just might be normal for this light. We shall find out soon enough. It’s still one darn nice light and would concider buying another one for Cerakoting.


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## RCLumens (Jan 8, 2012)

*Re: Object/Subject Review: Sunwayman T20CS (In Progress)*

Thanks for the in for Rokron, definitely notated, and very useful info!


----------



## shahzh (Jan 8, 2012)

*Re: Object/Subject Review: Sunwayman T20CS (In Progress)*

Just a quick one...does the T20CS suppose to memorize the strobe function after you turn off the side switch? Because mine goes to high when I turn it back on...:-(


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## Bigmac_79 (Jan 9, 2012)

*Re: Object/Subject Review: Sunwayman T20CS (In Progress)*

Hey, thanks for the heads up about the strobe. I had not noticed that in normal use, but after testing, I found this:

-When the light is on any brightness, the strobe activates and stays activated just fine.

-When the light is in standby for high mode, when you turn on the strobe it will strobe for a bout 5 seconds, then go to constant on high.

-When the light is in standby for medium, it will strobe for about 5 seconds then go to constant medium

-when the light is in standby for low, it will strobe for about five seconds then go off

-in each of these, another single press of the side switch will turn the light off, even for the case of standby from low going off after strobing

-in each of these, another double press on the side switch during the 5 seconds of strobing will activate SOS mode, which will stay on as expected until you turn it off. From SOS mode, another double press will send you back to strobe, and this time it will stay on as expected until you turn it off.

I don't know if Sunwayman did this on purpose for some reason, but in my opinion this is a poor way to handle the strobe. On the other hand, I've been using the light regularly for a while now and hadn't noticed this. I don't use strobe much, but I guess the few times I have it has been from when the light was already on.

For the question about the low voltage indicator: no, the red LED won't ever be on except when the main emitter is also on, so you don't have to worry about giving away your position or anything like that.

For the memory of strobe: no, the UI does not ever memorize strobe mode (or SOS mode), after you turn it off it goes back to whatever mode you were using before. This probably is intentional, as Sunwayman claims the strobe modes to be "hidden". Personally, I prefer it this was, as I don't use strobe modes often and really don't like being surprised by a strobe mode when I'm expecting to turn it on and get constant output.


----------



## shahzh (Jan 9, 2012)

*Re: Object/Subject Review: Sunwayman T20CS (In Progress)*

Hmm that's funny.....the rest is the same as above but mine when the light is in standby for medium, double clicking it will strobe for about 5 seconds then go to constant HIGHoo:. I also received an email from SWM that T20CS won't memorize strobe or SOS. Also I did asked SWM if its ok to leave it on standby mode for a long period and this is their reply: '_The standby current of T20CS is about 5oµA, you may leave it for 17 years on standby mode'_


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## RCLumens (Jan 9, 2012)

*Re: Object/Subject Review: Sunwayman T20CS (In Progress)*

Quick question back to run-time for a moment... On the chart it shows the light getting dimmer with each passing minute - So is this regulated, not regulated? From an ownership standpoint, on the hi (not turbo) setting, can you run the light for 30 min, or will it get dim? Reason I'm asking is that I'm also looking at the Thrunite Scorpion V2, but really like the SWM's interface, plus its a bit smaller... But the Scorpion seems to have regulated run time - a bit better perhaps? Many thanks!


----------



## Bigmac_79 (Jan 9, 2012)

*Re: Object/Subject Review: Sunwayman T20CS (In Progress)*



RCLumens said:


> Quick question back to run-time for a moment... On the chart it shows the light getting dimmer with each passing minute - So is this regulated, not regulated? From an ownership standpoint, on the hi (not turbo) setting, can you run the light for 30 min, or will it get dim? Reason I'm asking is that I'm also looking at the Thrunite Scorpion V2, but really like the SWM's interface, plus its a bit smaller... But the Scorpion seems to have regulated run time - a bit better perhaps? Many thanks!



On high, you're right it does get dimmer bit by bit. However, it doesn't drop very fast, and it's not noticeable as you're using it. Using 2xCR123 or 2xRCR123, you can see that the drop is gradual but pretty flat. On 1x18650, it's pretty weird, going down but then back up, but on average it's fairly constant for about an hour. You should also note that Sunwayman doesn't claim regulation on 1x18650, but only on 2xCR123 or 2xRCR123. So, the T20CS is regulated, but not perfectly. The output remains practically constant, if not exactly so.


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## RCLumens (Jan 9, 2012)

*Re: Object/Subject Review: Sunwayman T20CS (In Progress)*

Fair enough, so about an hour of useful bright light. Not bad... and in real terms I'm looking for usage that isn't based on instruments, (however that data is very useful) I'm looking for the normal usage perspective, so thanks so much for sharing that! Cheers -


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## jh333233 (Feb 5, 2012)

*Re: Object/Subject Review: Sunwayman T20CS (In Progress)*

Just got mine today, slightly disappointed by a few things
The white engraving tilted
Stains on grip ring
Dinged reflector (critical issue)
I thought the hotspot would be very tight like Crapfire C8, but it is as large as P60 or A2
Overall the light is cool, except these problems, couldnt wait until night
Btw, im quite worried about water leakage at the side switch since T40cs exhibited this problem mentioned in T40CS review


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## jh333233 (Feb 5, 2012)

*Re: Object/Subject Review: Sunwayman T20CS (In Progress)*

Another question, is it 20k [email protected] with CR123a?
Thanks


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## Bigmac_79 (Feb 5, 2012)

*Re: Object/Subject Review: Sunwayman T20CS (In Progress)*

I'm sorry to hear about those quality issues on your T20CS, especially a problem with the reflector. Did you get it from a reputable dealer?

With the water, as I mentioned in the review, I submerged mine for over an hour, clicking both the rear and side switch several times while it was under. I don't have any way to open up the housing of the side switch to look and see if any water got in, but my review sample has suffered no negative effects, so I'm assuming that no water got in.

With the lux, I assume your asking that because of the output graphs in my review. As I stated there, those graphs are measurements of relative brightness using a home made light box. What that means is, I have a photocell inside of a box lined with white paper. I shine the flashlight in through a hole in the top, and it's arranged so that none of the beam falls directly on the photocell, but rather light is reflected around in the box until it lands on the cell. This isn't a perfect measure of overall output (for that I'd need a very expensive integrating sphere), but rather gives a good general idea of how the output behaves over time. So, this is not a "lux at 1 meter" measurement of the hotspot, or anything like that. I currently don't have the setup necessary to do that kind of measurement, though hopefully I will in the future. I kept the value I measure on the graph, instead of converting it to percent output, because it is useful for making general comparison of one light to another, but only for other measurements using my specific light box (that's why I labeled it "MacBox Lux, because that's the only value it can be compared to).

Let me know if that doesn't make senese or doesn't answer your question .


----------



## jh333233 (Feb 5, 2012)

*Re: Object/Subject Review: Sunwayman T20CS (In Progress)*

Thanks for the reply
Ive got it from individual-dealer from local forum, previous V20c didnt have such issue, but i think this might not be the major reason
If SWM has a good QC, then this light shouldve never reach the world
2 dings and some dusts will not affect my normal use since ive got used to well-damaged reflector, by de-dusting with tissue and scratched it like hell
Lotta threads in reflector of my abused light, and im pretty sure that i rather to leave the reflector there than opening it and de-dusting by myself, it only worsen the situation


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## jh333233 (Feb 5, 2012)

*Re: Object/Subject Review: Sunwayman T20CS (In Progress)*



Bigmac_79 said:


> Hey, thanks for the heads up about the strobe. I had not noticed that in normal use, but after testing, I found this:
> 
> -When the light is on any brightness, the strobe activates and stays activated just fine.
> 
> ...


My version
standby-low, double click for 5 sec strobe
Hold button, short strobe then constant high

Strobing, hold button, return to high then cycles


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## Bigmac_79 (Feb 5, 2012)

*Re: Object/Subject Review: Sunwayman T20CS (In Progress)*



jh333233 said:


> Thanks for the reply
> Ive got it from individual-dealer from local forum, previous V20c didnt have such issue, but i think this might not be the major reason
> If SWM has a good QC, then this light shouldve never reach the world
> 2 dings and some dusts will not affect my normal use since ive got used to well-damaged reflector, by de-dusting with tissue and scratched it like hell
> Lotta threads in reflector of my abused light, and im pretty sure that i rather to leave the reflector there than opening it and de-dusting by myself, it only worsen the situation



I understand not wanting to open it up to try to clean it. Does the ding in the reflector cause the beam to look misshapen? It might be worth discussing with whoever you got it from, or if they won't do anything, sending a message to Sunwayman. They seem to be good at going the extra mile to deal with customer service issues.


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## jh333233 (Feb 6, 2012)

*Re: Object/Subject Review: Sunwayman T20CS (In Progress)*

Mostly, the beam is unaffected, or maybe an indistinguishable-few lumen loss, 658 with 5lm loss is acceptable and i couldnt even notice it
It was just an eyesore that a new light with dusty,2-dinged reflector, might not be so necessary to find SWM(i have 0 CS expectation to chinese manufacturer)
If i could get a can of de-dusting gas, i might try to do so, cause my mouth couldnt blow strong enough current


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## jh333233 (Feb 7, 2012)

*Re: Object/Subject Review: Sunwayman T20CS (In Progress)*

And last word:
Turbo doesnt comes on with single-cell for latest version of this light


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## Bigmac_79 (Feb 7, 2012)

*Re: Object/Subject Review: Sunwayman T20CS (In Progress)*



jh333233 said:


> And last word:
> Turbo doesnt comes on with single-cell for latest version of this light



I thought that at first as well, however, what I found out is that it is very hard for my eyes to distinguish between "turbo" and "high". I didn't figure it out until I had it hooked up to my light box. In order for my eyes to see the difference, I have to turn it on from the tail cap (so it's in turbo), then hold down on the side switch for two seconds so it goes directly into high without going off first. If I turned it off from turbo then back on into high, I couldn't notice any brightness difference, I could only notice a decrease in brightness when I went straight from turbo to high. 

Also, as you can see from the output graphs I did, when using an 18650, turbo mode will only be brighter than high for about the first hour. After that, the cell's voltage is too low, and high and turbo are the same output. So, you'll only be able to use turbo with an 18650 when your cell is relatively freshly charged.

Hope this helps!


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## peterharvey73 (Feb 7, 2012)

*Re: Object/Subject Review: Sunwayman T20CS (In Progress)*



jh333233 said:


> Thanks for the reply
> Ive got it from individual-dealer from local forum, previous V20c didnt have such issue, but i think this might not be the major reason
> If SWM has a good QC, then this light shouldve never reach the world
> 2 dings and some dusts will not affect my normal use since ive got used to well-damaged reflector, by de-dusting with tissue and scratched it like hell
> Lotta threads in reflector of my abused light, and im pretty sure that i rather to leave the reflector there than opening it and de-dusting by myself, it only worsen the situation



JH, would you regard this as a reputable dealer?
I know that in Vietnam, there are many retail outlets that specialise in selling "factory seconds".
However, they are not labelled as factory seconds at all.
They are sold as supposedly brand new, and genuine, in top condition, but for a reduced price.
Westerners who holiday in Vietnam often get sucked into buying factory seconds as brand new, because they don't purchase from a reputable dealer.
A few years ago, I remember a website in Australia, deliberately selling factory second Sony Vaio laptops, however they intentionally told us up front, that they were "factory seconds".

I know that Flavio @ bogusa was offering me dinged RRT-3 for a big discount, but he deliberately told me up-front that they were not in top condition.
I suspect your T20CS is a "factory second", sold for a discounted price???
I have three Sunway V10R's, and they are superbly built; even Selfbuilt says so in his reviews of Sunwaymans...


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## jh333233 (Feb 8, 2012)

*Re: Object/Subject Review: Sunwayman T20CS (In Progress)*

My first SWM, V20C shown fine even with 20% off (or gaining trust)
Anyway ive coped with the situation anyway, at least it is very satisfactory in terms of beam


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## peterharvey73 (Feb 8, 2012)

*Re: Object/Subject Review: Sunwayman T20CS (In Progress)*

Oh, it was your T20CS that was a total dud?
Are you sure that T20CS wasn't a factory second???


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## jh333233 (Feb 8, 2012)

*Re: Object/Subject Review: Sunwayman T20CS (In Progress)*

I assume it doesnt suppose to be


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## Bigmac_79 (Feb 8, 2012)

*Re: Object/Subject Review: Sunwayman T20CS (In Progress)*

I added some more beam shots to the OP, along with a few long term impressions.


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## Frakymjay (Apr 8, 2012)

Hi, i am a novice SWM T20CS user. Had been running the light with 2x 16340 and enjoying Turbo, High, Mid and Low during my regular outing. Recently tried out 1x 16850 but only able to have all setting minus the Turbo.*

My understanding is that depressing the tail button will give out turbo and follow by press hold the front switch for alternate choices. Shining at the wall with 2x 16340, I am able to visual judge a total of 4 brightness when the turbo drop to high and accordingly. But with 16850, there is only three brightness output. When I pressed the tail switch to on, seem to me it will go high, mid to low...

Is there anything i'm missing? Dear all, any enlightenment greatly appreciated!


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## Bigmac_79 (Apr 8, 2012)

My experience has been that when using an 18650, it is pretty hard to tell the difference between Turbo and High, and when the battery starts to get used up, there is no difference. I didn't think there was a turbo mode until I used my light box to make real measurements.

After measuring that the Turbo mode really is a higher output that High, I found that with a fresh 18650, I could see a visible drop in output when I switched from Turbo to High without turning the light off in between.

Because it's better regulated with 2x16340, I can always see a difference between Turbo and High using those batteries.
Sent from my mobile device. Please excuse brevity and typos.


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## Frakymjay (Apr 8, 2012)

Thanks a million for the very fast feedback, chief! It is especially assuring to have a Pro feedback! 

In that case, with Turbo as my main preference. Between 1x 18650 and 2x 16340, may I ask which is of a better alternative?


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## Helmut.G (Apr 8, 2012)

If the difference between turbo and high matters to you, use two batteries.
If you want runtime, go with the 18650 as it has a much higher capacity.


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## Frakymjay (Apr 8, 2012)

Sweet!


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## Bigmac_79 (Apr 8, 2012)

I would really recommend 18650 either way. By the time the Turbo on an 18650 drops to match High, the 2x16340 will be pretty much dead.

Check the runtime graphs in the review to see what I mean. Imho, 2x16340 has very few advantages in this light.

Sent from my mobile device. Please excuse brevity and typos.


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## Rokron (Apr 8, 2012)

I've played around with the 2x16340's and I agree with Bigmac 79 on using the 18650. The T20CS puts out plenty of light on high for me with a 18650 and I don't have to worry about the battery craping out. If I need more throw I'll fire up the TK35.


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## Vinniec5 (Aug 1, 2012)

Thx for the great review Bigmac79, I came across this by accident as I was looking for another Sunway review on the c20c. I wound up ordering both the T20cs and c20c as a compact thrower companion to my SF fury and V60C, The T20cs reminds me of a SF U2(I miss mine). I was going to get the SF Lawman to take on a trip with me but it isn't a thrower and batteryjunction(and others) were out of stock on the R1. guess I missed this coming out from Sunwayman, from your beamshots it should work great for me as i trying to travel light as possible and carry lights that can use all 18650s or CR123 batteries so I only have to carry one charger


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## Bigmac_79 (Aug 1, 2012)

Vinniec5 said:


> Thx for the great review Bigmac79, I came across this by accident as I was looking for another Sunway review on the c20c. I wound up ordering both the T20cs and c20c as a compact thrower companion to my SF fury and V60C, The T20cs reminds me of a SF U2(I miss mine). I was going to get the SF Lawman to take on a trip with me but it isn't a thrower and batteryjunction(and others) were out of stock on the R1. guess I missed this coming out from Sunwayman, from your beamshots it should work great for me as i trying to travel light as possible and carry lights that can use all 18650s or CR123 batteries so I only have to carry one charger



Glad you appreciated the review! I actually have one in progress on the C20C as well, but it looks like you'll get to compare them for yourself :thumbsup: The T20CS is one of my favorite compact throwers. I'v also been pretty impressed on the throw with the C20C, the head is barely larger than the head of a V11/V10, but it's got a surprisingly good spot.


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## Vinniec5 (Aug 2, 2012)

both should be here tomorrow, looking forward to testing them out


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## rustlerdudr987 (Aug 3, 2012)

I Guess im a little confused does this light not perform (light output) as well while running on a 18650 vs. the cr123?


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## Bigmac_79 (Aug 3, 2012)

rustlerdudr987 said:


> I Guess im a little confused does this light not perform (light output) as well while running on a 18650 vs. the cr123?



It depends in what you're looking for. The CR123s maintained a slightly more constant brightness, but the 18650 had a much better run time overall.

Sent from my mobile device. Please excuse brevity and typos.


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## Vinniec5 (Aug 6, 2012)

still waiting Bigmac, the C20C came and that's a nice portable light. nice throw for a small head but batteryjunction accidently sent me the T20C not the T20CS and I'm going away FRI too. I wanted to take it with me to use it. Hope me and BJ can fix this before I leave.


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## Bigmac_79 (Aug 6, 2012)

Vinniec5 said:


> still waiting Bigmac, the C20C came and that's a nice portable light. nice throw for a small head but batteryjunction accidently sent me the T20C not the T20CS and I'm going away FRI too. I wanted to take it with me to use it. Hope me and BJ can fix this before I leave.



Sorry to hear that, that's always disappointing. I can hear some intern getting lectured right now on the difference between the "T20C" and the "T20CS" . I've had pretty good communication with BJ in the past, I wouldn't be surprised if they got the new one to you before the weekend, especially if you communicate the situation. Good luck!


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## Vinniec5 (Aug 6, 2012)

I'm not upset about it, I understand its a simple picking error. Batterj has always treated me fantastic and mattk on here has always gone out of his way for me getting parts and checking stock. I don't blame them mistakes happen, its just my luck though things like this always happen to me before I need to go somewhere or when i'm trying to do something



problem handled by Nick in Cust service at BJ. I'm going to keep the T20C( i like it it reminds me of the SF C2 plus it has the stealth clicky switch) they are going to charge me for the T20C but send the T20CS i paid for on the original order so their inventory comes out right and i get the T20CS ASAP. the t20c fills the gap after i sold almost all my C2-G2-3s win-win all around. Nick even called me at home to fix it as fast as they could. can't ask for more than that

8/9/12 T20CS came today, what a great light!!! can't wait till tonite to test the throw outside but just a quick basement try and this looks like a winner. Reminds me of a U2 with a combat grip


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## Vinniec5 (Aug 10, 2012)

The T20CS should be called the chain saw, as this little monster saws right through the dark. Great balance of excellent throw with just enough spill to fill the area. Definitely glad I saw your review Bigmac. I personally like the two switches and the what I call Panic mode default on the rear button to Turbo with the battery gauge a needed bonus


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## Bigmac_79 (Aug 10, 2012)

Glad to see you received and are enjoying your light :thumbsup:

Sent from my mobile device. Please excuse brevity and typos.


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## Southpaw1925 (Oct 27, 2012)

lanternetactice said:


> i got this flashlight 1 week ago. excelent flashlight, better than Olight M21X and Thrunite TN10.
> 
> I make some test outside, and i think so this flashlight will have a huge success.
> 
> i like how to change the intensity, it's easy, beautyfull smooth reflector, and last but not least it's a beautyfull flashlight. I love Sunwayman because they give a very good look for flashlight.




I'm undecided between the tn10 and t20cs. What do u like about the t20cs over the tn10?


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## gilson65 (Apr 9, 2013)

just waiting for my swm t20cs to arrive was thinking about running keepower 3400mha in it very new to 18650 design torches and wondering will they be ok to run in it.Also any potential issues with the t20 cs some 12 mnths on. Thanks tony


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## tony_roti (Oct 21, 2013)

Hi Bigmac_79

Mine just arrived a few days ago. I bought it from dx based on your review and based on positive evaluations from other users. And because I wanted it so badly. It took forever to arrive but finally arrived (somewhere in Romania).:twothumbs


It came in a cardboard box that looks like in your photos and with the same accesories as you describe it, with a sticker on the side with the 
model number and a few specs. But I got curious when I saw a second sticker with: *Premium XM-L2 LED Higher Performance*.





I looked at the light and indeed, the led is the new emiter from Cree XM-L2 instead of XM-L U2. The bin has two bonding wires, and the die has dots instead of lines. See the pics. From specs, the new emiter is 20% brighter than XM-L.

Very, very bright light on Turbo mode from a flashlight with 658 lumens output. I compared the light with XTAR B20 Pilot wich has XM-L U3 
emiter and 1000 lumens output capabilities and both appear as bright (eye compared). Only color temperatures is different.




The picture with the new emiter is not mine because i wasn't able to produce a macro like this with my camera.

Excellent review by the way. Thanks for sharing with us.


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