Fenix BT20 xm-l NW bike light review

Ti²C

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For submission in the Reviews forum

Hi Cpfer's,
Here is a translated version of my original review of the Fenix BT20 (first part), wich can be found here

Because of my limited skills i won't provide the sharp technical reports you're used to read thanks to the CPF's experts :thumbsup: but rather a general opinion on what a lambda user feels using this product.


this pre-series model suffers from a bug of the battery level indicator : in "turbo" mode it will turn red a few minutes after ON, Fenix ​​is ​​aware of this problem and assured it will be corrected.



Fenix first attempt in bike lighting should offer excellent performance and reliability, at least that's what i expect from a major manufacturer of led torches.
The Chinese manufacturer offers two models based on xp-g and xm-l, but given the expertise of Fenix in high power torches i believe there will be even brighter models if success is confirmed.


To promote their lamps, the manufacturer ​​started a contest earlier this year to search for testers across the world : This is an original method of promotion but it's also double-edged in case of major default or design fault: we must believe they are confident in their products !



Let's see what features that BT20
icon_wink.gif




Unpacking:

courrier.jpg

boitey.jpg

boite2mg.jpg




interboite.jpg



Unusual detail for a bike light, there is no charger or rechargeable batterie supplied .
Some may blame this shortcoming, I think on the contrary that it has several advantages:

- Any self-respecting flashaholic already own its quality batteries and chargers
- When new technologies emerge it's easier to switch to better batteries
- The global price of the pack is reduced.



lampe.jpg


The front part and rear heatsink are made of aluminum, the upper is plastic.
The solid impression generated by the set is conform to what i usually expect from Fenix's flashlights, the mount feels solid on the handlebars and even in intensive use it should not move too much to be a concern !

faceavantr.jpg


we can see the work on the reflector and the lens (it reminds me of the hybrid reflector lamps from ITP)

detailreflec.jpg


lens is made of some kind of polycarbonate: it is unusual for Fenix ​​but it is certainly made necessary to draw the "striages" on the upper part.




dessusg.jpg


button is illuminated when the lamp is turned on to inform the level of battery / batteries, by a red/green backlight.



arrierei.jpg


Phillips screws locks the lamp
icon_wink.gif
it's easy to open and access to internals.




fix2f.jpg

fixations.jpg


connecteurg.jpg


the connector looks good with a strong and secure locking.





the battery case, made of plastic :
2*18650 or 4*cr123,
16340 are banned

boitierpi.jpg


boitiersup.jpg

boitierinf.jpg


double marking for battery position is visible, but a physical or more easily identifiable reminder would have been a plus in the dark.

there is a small tab that prevents closing the lid the wrong way: perfect
icon_wink.gif


detrompeur.jpg


dtrompeur.jpg




etui.jpg




supportcax.jpg


the headband holder, gadget or true value ? i've not tested it yet, but i feel like it will rise the light too much on the helmet to feel confortable...


rallonge.jpg







included manual:

featuresv.jpg


casquegu.jpg


guidont.jpg


techm.jpg



i've found the spacing between levels appropriate althought there should have been a bigger gap between mid and high mode : i would have liked something more like 50/150/450/750.
what bother me is the flashing mode which alternates a slow then fast "strobe" : it's useless in this form, I would have prefered that it remains slow around 2 or 3 Hz max.


mounting:

note the ridiculous size of the BT20 for a 750lm headlight !
I kept a Quark 123² neutral xp-g as backup in case of a sudden shutoff of my 18650's.


2guidon.jpg


with 3 different types of o'rings provided and the opportunity to orient the lamp longitudinally, we can easily find a location for the BT20, even on oversize handlebars.

2guidon2.jpg


2guidon3.jpg



I placed the battery pack this way while waiting to find a better location (with extension included of approximately 70cm, it should not be a problem to find a place)

2packbatt.jpg


2packbatt2.jpg



what would be great is a 4x18650 pack of the same size as a bicycle water bottle, this way it could fit securely in the bottle holder
icon_idea.png



while being in front of a wall (yellow, please ignore the color) i'd like to show you the effect of the lens and hybrid reflector compared to a regular textured reflector.]


2beamquark.jpg


with the quark the beam is classical with spill / spot and "corona" at the junction.




2beamshrouge.jpg





The BT20's beam is quite particular:


bt20spill.jpg



-there is a wide but concentrated spot typical with smooth reflectors lamps which should provide a good range
-a "two-step" spill which I think provide a good width lighting.
-on the lower section of the spill / spot a "tongue" of light wich should theoretically create better illumination right before the wheel.

you can also notice that the upper part of the spill is truncated compared to a conventional reflector, which should reduce glare for other road users that we will cross.


pics are taken 1m from the wall, the result should be more demonstrative outdoors.














Beamshot s:

First attempt beamshots: I also took my sc600w to have a relevant point of comparison. (althought being a general purpose flashlight, the sc600 with it's wide beam, and similar price was the closest competitor in my collection..)



The neutral color of the BT20 is colder than the zebra, I guess it's tint is in the 3b/3c/3d range.
It is not warm enough to my taste, but it is enough to avoid the "green" tint while keeping a high Bin.



The efforts of the manufacturer to provide improved color rendering is still commendable for a product intended to be used in mountain biking, although the contribution is difficult to quantify by eye (even in neutral flavor, xm-l's [email protected] is not impressive )


* F/2.8, ISO80, 24mm eq., 4 ", manual WB
bs1mulsc600w.jpg

sc600w

bs1mulbt20.jpg

BT20




bs2mulsc600w.jpg

sc600w
bs2mulbt20.jpg

BT20



other place, with exposure time reduced a bit:

* F/2.8, ISO80, 24mm eq., 4 ", manual WB
bs3pompcs.jpg

control

bs3pompsc600w.jpg

sc600w

bs3pompbt20.jpg

BT20



bs4pompsc600w.jpg

sc600w

bs4pompbt20.jpg

BT20


my first impression:

This is quite surprising when you're used to the usual zebra-flood beam, but the "immediate vicinity" of the BT20 is even more powerful by a substantial margin !
as if we've set a lamp voluntarily lower to illuminate closer with the "spot" section of the beam, except that in the case of the BT20 you still have a long distance illumination.



:wave:
 
Last edited:

nobunaga88

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Jul 10, 2011
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Nice review,another little monster for my bike :D
it's very helpful for me to decide :)


I just wondering about the flashing mode, is it a strobe mode or a beacon mode?
Hopely it's Beacon mode which is very useful while commuting... :twothumbs
 

Ti²C

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Jul 27, 2009
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France
Nice review,another little monster for my bike :D
it's very helpful for me to decide :)


I just wondering about the flashing mode, is it a strobe mode or a beacon mode?
Hopely it's Beacon mode which is very useful while commuting... :twothumbs


Hi,
unfortunately it's a sequence of slow blink (around 2hz), pause and fast strobe.
every review i've read about this light also points this fact, hopefully the final versions will have a modified and more appropriate sequence.
 

moozooh

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Joined
Dec 11, 2011
Messages
492
Well, this light seems to stand its own against SC600w. The runtimes are great, and I quite like the amount of light it puts out, although I find it funny that this anti-glare design somehow manages to reach treetops. :) For the record, I've been using SC600 for night-time commutes myself, but it is in a city with insane light pollution. So between SC600w and BT20, the latter seems a clear winner, but now I'd like to see what SC600w mk2 can do.
 

B0wz3r

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Sep 26, 2009
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Very nice review!

It looks like a decent light, but it's too bad they use those crappy rubber bands for attachment; I've come to hate them, as they've never worked well for me. I'm also done with the hassle and bulk of external battery packs. For my needs, the 1x18650 lights I have give me more than enough run-time.
 

Ti²C

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Joined
Jul 27, 2009
Messages
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Very nice review!

It looks like a decent light, but it's too bad they use those crappy rubber bands for attachment; I've come to hate them, as they've never worked well for me. I'm also done with the hassle and bulk of external battery packs. For my needs, the 1x18650 lights I have give me more than enough run-time.

althought it's not the best solution if you intend to remove the light frequently (a quick release à la Niteye would have been a plus for this purpose), i've found this mount option to be one of the best alternatives : cheap, solid (the light don't move), and versatile.
 

B0wz3r

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althought it's not the best solution if you intend to remove the light frequently (a quick release à la Niteye would have been a plus for this purpose), i've found this mount option to be one of the best alternatives : cheap, solid (the light don't move), and versatile.

Two-Fish lock-blocks. Simple, cheap, easily removable, solidly holds most any light.
 

B0wz3r

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Sep 26, 2009
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they (twofish) do the job for road purpose, but for MTB the light moves way too much !

That's a simple problem to solve.

Just put a turn or two of the old-style road bike cloth handle bar tape around your bars where you're going to put the lock-block.

If you want to get really extreme about it, and make sure your light absolutely won't move, just cut a small strip of grip-tape like they use on skateboards, instead of the cloth handlebar tape.
 

zacster

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Jan 5, 2013
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I don't like that rubber band strap mount either. It seems rather cheesy for a branded light. That's something I expect from a cheap eBay light. I also don't like the battery pack. 2 18650s can be easily made part of the unit.

This whole setup looks like a kluge to me.
 
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