review: Maxtoch Xsword L2K LEP flashlight (2021 edition) reaching over 3km

I can totally understand! And these are not budget lights. I hope they will become more affordable sooner than later..

That is a very serious flashlight, but the price is also very serious.

Just seen the current on high. 1.4A on high isn’t that much at all - no wonder it can sustain high candela for so long. Does it get warm at all?

I’m guessing the short cell version can easily sustain the same candela until the cells run out too.

In fact I measured the tiny Cyansky M3 with a 16340 cell at hitting more than that at turn on and sustaining 0.8A for an hour. I wonder if you could make a tiny LEP following the same ideas as the GT Nano.

Let’s get ballpark figures of the diode. 1.4A*8v=11.2W of power. We’ll call that 11-11.5W with some the minimal amount of voltage sag from the 1.4A discharge and voltage drop over springs.

It’s a buck driver. Let’s assume it has about 90% efficiency so we’ll get 10W to the laser diode.
Using the input/output wattage of a cheap laser diode given on DTR’s website we see that 10W input translates to approximately 2.8 W of laser output. I’m assuming they’re using a similar laser diode. Higher power, more efficient ones exist but they’re more expensive. A Nubm44-v2 produces 4 W of laser output at 10W input but it’s more than double the price on DTR’s website and they probably wouldn’t spring for a more expensive diode if they don’t need the power.

I’d estimate the laser is probably outputting 2.5-3W of power so the light is only producing about 8W of wasted heat to produce the laser.

I believe we don’t have the data to calculate the efficiency of the phosphor (Would have to be measured right near the phosphor).

I don’t know how to convert lumens to watts since we don’t know the different wavelengths produced.

It’s using a pretty powerful laser, 3W is deep into class 4.

Marco, it would be valuable if you could measure the amperage the laser diode itself is getting inside these LEPs after the buck/boost drivers do their work. Then we could get a better idea of what the diode is.

Voltage would be useful too but that’s more difficult since you’d need to have direct access to the exposed leads whereas amperage can be done with just a clamp meter.

Thanks for your reviews! They’re very informative and helpful. Keep up the good work!

Be aware you can’t compare the 1.4A as an absolute figure. It has a 2S battery configuration.
That equals 2.8A in a 1S configuration. (8.4V * 1.4A = 4.2V * 2.8A)

I agree. At 1.4A, even the slim 2*20350 version should have adequate runtime and full regulation. These are minimally useful lights to begin with, and I can’t imagine ever needing more runtime than what the 20350s would provide.

I might be irresponsible and buy this if there’s an attractive enough coupon AND it’s valid on the slim model.

Thanks for the review!

PS: Seriously. I love, love, love the throw vs time graphs. I really think this should be done for every throw-oriented light review. The comparisons between things like a NM1, PM1, and 90.2 would really help get a feel of usable throw

And another of my 2cents to those waiting out LEPs. I’m concerned this might be the best and maybe last time to buy these things. I have a strong sense that they’ll be discovered and outlawed in the near future.

It depends. I think we’re still at least a few years out and a couple dozen plane strikes away. LEPs are still pretty expensive that they’re not something the masses would buy. Anyone can buy an incredibly dangerous laser on eBay for $5 that is powerful enough to be hazardous to planes so there’s a barrier to entry with LEPs. Laser modules/parts are still not banned from being imported, just assembled handheld lasers.

I hope you’re right

Someone needs to make a single 20350/18350 50mm GT mini sized LEP with a buck/boost driver. You may ask “why should someone make this?” Well because I WANT it. Now stop asking questions and get to work!

That’s awesome. I also love the lep lights. I only own two at the moment. I’m patiently waiting for one that has the option to zoom out. Even to zoom out just a little bit is all I ask. So it can be used for general lighting. Not sure if they can even make this possible. At least make the low a very low low imo.

There are 3 that I know can do that, Optispike S50 , Lightstorm S90 , Acebeam W50 .

I'm not sure there is enough space in a mini sized flashlight for the classic LEP module. There should be enough space for the one that is used in the Astrolux WP1 and WP2. That's only about 1 cm diameter and about 2 cm long.

About LEP flashlights being outlawed, that might be a valid concern, but not yet. The more we treat them with care, the longer it probably takes before these kinds of laws need to be put in place.... if they have to be put in place.

Well the 20350 version is 181mm long. With only one 20350 that could be shortened to 146mm and even more if a side switch is used. It would only last 25 mins on one 20350 but It’d be a pretty fun compact light and you could always switch to a 21700 if needed.

true, but a GT mini has smaller dimensions than a shorty L2K.

Discount code:

$30 off

use coupon: X1LU299

can be used on long and short version:

Long version: https://www.aliexpress.com/item/32949195871.html(link is external)

Short version: https://www.aliexpress.com/item/1005002237755766.html(link is external)

Can only be used up till April 30, 2021. Currently 10 codes available, but more can be added.

There is another code for $79 off, but I will use that for a giveaway. (only a few available)

I might get one with the $79 off code but first I have to find out if there’s any import tax. How much further can you see with this compared to the Nealsgadgets LEP? Is the difference noticeable enough to justify the extra price? Let’s say you turn it on from cold at 40% battery, will it still come on at the full 450 lumens? Also 20350 seem to be impossible to find in the UK. I managed to find a couple sellers that have the vapcell 18350 but all others are out of stock.

Good questions.

For both you need a scope to really see anything beyond a few hundred meters ;)

Yes, the 26650 and L2K are different beasts. The 26650 unbranded LEP is a fine flashilght for the money, but the L2K beats each and every flashlight out of the water, especially after the first 5 minutes

Thanks for the quick reply. So is the small brightness drop we see on turbo due to the laser heating up? If you let it cool down and turn it on again will it come on at full brightness? I want the 20350 version but will only use it for less than a minute at a time. I just want to be sure that it’ll come on at max brightness even with those weaker cells.

If you look at the graphs, you can see that the drop is very minimal (that's why this is such an interesting light). You won't be able to notice the difference. This is not a high power SBT90.2 flashlight that drops to AA flashlight territory ;) in 2 minutes