REVIEW: Nightwatch NI40 Stalker [26650, dedomed 3V XHP50.2, beefy C8], with SST70 mod

LED Flashlights – General Info 26650 Flashlights
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Nightwatch NI40 modded with SST70 6500K dedomed and XHP70 boost driver

Recently I have swapped the dedomed 3V XHP50.2 in my Nightwatch NI40 for a dedomed SST70 6500K. As the SST70 is a 6V led, I had to use a XHP70 boost driver. The boost driver is from MantaRay, has four modes and delivers 5A. In comparison to the dedomed XHP50.2, the shaved SST70 has a smaller hotspot with more throw, produces less heat on turbo and is maybe slightly less bright.

I shaved the SST70 6500K close to the phosphor with a razor blade to get more throw and more neutral white light color. It is a bit above 5000K, maybe around 5500K and has some green in the beam. Below some fotos:

Close look at the shaved SST70

If you shine a light from the side at the led you can see that the bonding wires on the phosphor are soldered to a shiny dark green pad.

Some whitewall beamshot comparisons (all at 5000K, 30cm from wall, flashlights from left to right):

Nightwatch NI40 SST70 shaved ~5500K, Sofirn SP31 V2.0 5300K, Wildtrail BLF D80V2 SST40 5000K

Nightwatch NI40 SST70 shaved ~5500K, Astrolux FT03 SST40 5000K, Convoy C8+ SST40 5000K

Nightwatch NI40 SST70 shaved ~5500K, Sofirn C8F XPL HD 5200K, Emisar D4S Nichia 219C 5000K

Nightwatch NI40 SST70 shaved ~5500K, Sofirn SP70 XHP70.2 5000K, Convoy L6 XHP70.2 4000K and resistor mod

Outdoor beamshots

Comparison of the dedomed XHP50.2 and the dedomed SST70 in the Nightwatch NI40 (3.2s, F7.1, ISO 400, different seasons as you see, tree at 150m). The different sizes make a comparison a bit difficult. The XHP50.2 has a bigger hotspot while the SST70 is more concentrated.

This is the FT03 SST40 5000K at 150m.

The tower you can see in the following pictures is at 700m distance.

Control

Nightwatch NI40 with dedomed SST70

Astrolux FT03 with SST40 5000K

Astrolux MF02 with XHP35 HI 4000K

Animated

As you can see the Nightwatch NI40 with the dedomed SST70 led has a bit less throw than the Astrolux FT03 SST40 but it is pretty comparable. The throw is decent for the smaller reflector. With the XHP50.2 the NI40 barely reached the tower at 700m. I don’t have comparison fotos at 700m as the XHP50.2 is no longer in the NI40. Maybe the difference would be more noticeable if I would mod the driver to deliver 6A current.

EDIT: The previous beamshots of the NI40 have been replaced with fotos of the actual turbo mode that is hidden and can be activated only with a fast double click.

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New sst70 as in the round led? And if so can you provide a link?
Thanks.

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I bought the new Luminus SST70 on Taobao. It is still in the chinese warehouse and this mod will have to wait until next year. The Taobao link is:

https://item.taobao.com/item.htm?id=600044881463&spm=1101.1101.N.N.940fb8c

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Thanks, and btw nice review :+1:

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Nice review!

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As promised I have added the SST70 mod.

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Outdoor shots? Comparison to XHP50.2DD?

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I have added the outdoor beamshots now.

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I have replaced the previous outdoor beamshots with new ones that show the actual turbo. I noticed that the turbo is hidden and can be activated only with a fast double click. The NI40 gets hot faster and throws further with turbo.

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Do bare 21700 cells fit without being crushed in this light?

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I would not risk it because the springs in the NI40 are very stiff and made of thick wire.

The 21700 battery sticks out and would pretty sure be crushed because with the anodized threads on both sides you have to screw on the head and tailcap fully to make contact. Here are two pictures, 21700 Samsung 30T and 26650 Liitokala. Mind that the tailcap spring has almost no tolerance as it is 1.6mm thick.

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I’m not too sure how battery protections work but I saw you mention that the Stalker has a built-in PCB, does that mean the battery does not have to be protected? I see you barely fit the unprotected and mention that the spring has very little flex. I assumed a protected battery in such a beast was a no brainer but now I’m not sure what I need and it seems it wouldn’t even fit. Am I correct to assume that with a PCB built-in, that a flat-top unprotected is the correct battery and likely the one the manufacturer intended to be used?.

I have one on the way and want to make sure I don’t order the wrong cells. Thank you for the great review.

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The Nightwatch NI40 Stalker claims to have a low voltage protection. I did not test it but most flashlights have it, meaning that they turn off when the battery voltage goes below 3.0V.

I tried a protected battery and it looks much like the 21700 cell above. I don’t think it will fit as protected 26650 cells easily reach 70mm in length. The NI40 seems to be designed for 65mm long cells. Also, protected cells have certain currents when the protection trips. With the current getting over 10-15A (depends on the cell, maybe even 5A) the flashlight will simply turn off. The 3V XHP50 draws around 18A and you will not get a Turbo mode with a protected cell.

I would recommend you to use a flat-top unprotected 26650 from well-known reputable brands. If you use a flashlight with low voltage protection and a decent charger you will not have problems even with unprotected cells. If you are not sure how to handle Li-Ion batteries adequately look for Lithium Ion battery guides here on BLF.

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Thank you so much for the info, I guess I’m going with the Shockli. Actually, what brand do you like for this light?

In the flashlight description it only asks for a 26650 Battery and thats it. So is it safe to assume generally speaking that if a manufacturer just gives a battery size without mentioning button top or protected that means a regular unprotected flat top is ok?

I’m waiting on the Sofirn Sp36 to arrive and that one says it needs 3x18650’s only so I’m guessing any flats will be fine. Then I’m waiting for the Haikelite MT09R and that manual says 18650 Button tops with anti-reverse & anti-discharge protection. So that light likely has no protections built in and I MUST use protected buttontops at all times?

Sorry, don’t mean to veer you off course too much, you just seem knowledgable about this.

Edit: Actually I just checked Amazon’s listing of the Sp36 BLF and it says button tops are required and flat tops cannot be used. Sofirn doesn’t say tht at all but Amazon make this very clear. Does that mean I could also use the protected buttontops I’m buying for the Haikelite? Or can protected batteries be used only on flashlights that explicitly say Protected?

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You’re welcome. Most of my knowledge about flashlights and batteries comes from reading a lot on BLF. I’ll try to explain you a few things about batteries.

In my NI40 I use mostly Liitokala 26650 batteries. They are rather cheap with an acceptable performance. Those who have the best performance and top notch cells are certainly Vapcell, Shockli, Keeppower and some others. Here is a list of the reputable sellers where you can buy good batteries: Massive post on where to get lithium-ion batteries everywhere in the world! Look at Post 2-5 for info, And Canada Post 123

Flat top unprotected batteries will fit almost all single cell flashlights. It depends on how long the battery tube is and on the spring tolerances if a protected cell is suitable or not. Sometimes the description tells to use batteries with more than 10A continious discharge. Then they mean unprotected high drain cells.

The Emisar D4 or the Lumintop FW3A for example fit only unprotected flat top batteries. Flat top is how they are sold by the manufacturer.

Other sellers will add a protection or a button top. A protected battery is not the same as a button top battery. Most protected batteries have a button top but not all button top batteries are protected. Many flashlights with 3 or 4 batteries and battery carriers require unprotected button top cells.

In the SP36 there are 3 18650 batteries. They need to be unprotected because protected cells would be too long. They also have to be button top because there is a brass ring at the head where flat tips would not make contact because usually the positive pole is slightly lower than the surrounding shell of the battery.

You should use unprotected button tops also in the Haikelite MT09R. It has plastic rings around the positive button that prevent contact on flat tops and are a mechanical reverse polarity protection. The MT09R is a high power flashlight with 3 XHP70.2 that need a lot of current in direct drive. With protected cells it would flicker and simply turn off in turbo mode. It has all necessary protections because it uses the NarsilM firmware and the BLF members who developed this firmware and the corresponding drivers are true experts.

Generally speaking, all high power flashlights that use the XHP70, XHP50, SBT90.2 and multiple emitters need unprotected batteries These flashlights also have low voltage and reverse polarity protection. If you see lumen values over 3000 lumen you can be certain that these flashlights use unprotected cells. You can find out if flat top or button top by reading the description or reviews.

For more information about batteries, leds, drivers and flashlights in general check out this reference guide: LEDs & Other Stuff - (Reference Guide)
There are the battery tests by HKJ, the safety guide and links to useful information about batteries.

Hope I could help you. The Sofirn SP36 and the Haikelite MT09R are two great choices.

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You helped me tremendously. I was really confused about all this and now I feel far more informed so I thank you sincerely.

If you don’t mind, allow me to give it one crack to see if I’m learning. I’ll very likely be buying the Nightwatch NSX3 NS53A. Since it’s over 3k Lumen, def no protection, and since it’s not in a battery carrier, a flat top is correct. So for that one I’d buy a 21700 unprotected flat top. Is that correct?

Thank you again so much for taking the time to help me with this.

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I’m glad I could help you.

Yes, that is correct. The Nightwatch NSX3 NS53A uses 3x Xhp50 3V which is a very current hungry led. For the maximum brightness the best high discharge 21700 is the Samsung 30T. It will heat and stepdown fast. If it doesn’t matter for you to reach the declared 9900 lumens a Samsung 40T or a Molicel P42A should be enough and give more runtime.

Let me remind you to treat these high discharge batteries well. Never risk to short circuit them, store and transport them in plastic cases, use a good charger and be careful not to heat or puncture the cells.

There are only these few basic rules to follow and your unprotected batteries will work fine. In the category of the 3x Xhp50 3V flashlights there are also the new Lumintop FW21 Pro and the about to come out Astrolux EC03.

Have fun with your flashlights! May BLF always be a source of knowledge and inspiration for you.

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Thank you once again… Following the battery rules is very important from what I see in all the websites that sell them. They have hefty warnings and even require acknowledgments to make sure you understand. I appreciate the quick rundown.

I sure wish I would waited for your response. I bought 3 40T’s thinking those would be the better ones. I should have researched first. Live and learn.

Anyway, I did consider the FW21 Pro but ultimately didn’t like all the complaints others had about possible quality concerns. I also liked that Nightwatch took heat dispersion a bit more seriously than Lumintop did on such beasts. Ultimately since the lumens were similar, I chose my preferred host which was easily to me the NSX3. I will be checking out the AstroluxEC03, hadn’t heard about it.

I absolutely have received inspiration and have been bestowed a tremendous amount of knowledge in my short time here at BLF, I can’t imagine how that would be changing anytime soon.

Thank you again sincerely.

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Yes, lithium ion batteries have a high energy density, a low internal resistance and can release high current in short time. That is why short circuit would be dangerous. However, you have lithium ion batteries in almost any device today, notebook, smartphone, e-bike …

The 40T’s are a good choice. They are rated for 30A discharge, the 30T’s are rated for 35A. You will not notice any difference in startup turbo brightness because a difference of 10000 lumens to 8000 - 9000 lumens can only be measured but not seen. After a few seconds the 30T’s voltage will sag and the current will be reduced anyway. Also, a flashlight of this size will get scorching hot in less than a minute. Additionally, the 40T gives you more runtime.

You are starting a nice flashlight collection I see. :sunglasses:

You’re welcome. :slight_smile:

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Thank you good sir. I do like to think I’m starting a nice collection and am pretty happy about it. I love my KR4 so much. The MT09R and Sp36 are super exciting and I can’t wait til they arrive. But I do have to say that something about the 2 Nightwatch’s on their way seem like some pretty special lights. I’m actually in love with both of them.

I say I’ll be good after I get these lights, but the more I read here at BLF, the more I realize how absurdly foolish that sounds and how everyone at some point here thought the exact same thing.

A million thanks again.