My Bike Lights - Info, Teardown pics, Beamshots, Current Measurements, etc. . .

As much as I like high cri emitters for some things I prefer the sharper contrast that a cooler tint like 1D gives for night trails. That mod sure turned out nicely though.

I've been slacking off on keeping this thread updated. I've picked up one of the most popular and probably best bang for the buck bike lights out right now, the NiteFighter BT21 sold by GearBest (currently only $22.19 which is a steal!). It comes neutral white (3C I think), with very good thermal properties (i.e. mostly solid wall behind the emitter plate) and the full kit comes with a very good battery pack built with BAK cells. It pulls about 2.80 on Turbo (on an 8.4v pack, so 2.8A per LED). It can also be modded with various optics available. The only real issue with it is the plastic mount has very thin plastic where the screw attaches it to the lighthead. I've replaced mine with an aluminum one from DX, but plan to do a custom finned vancbiker gopro mount (see MTBR's Lights & Night Riding forum). The MTBR thread for this light is here.

My Current #'s:

Low: 0.12A
Med: 0.48A
High: 1.26A
Turbo: 2.70A

Modes are L-M-H-Turbo-L-M . . . with off being a long press from any mode. I believe there is a hidden strobe activated with a quick double-click (can't remember for certain).

I don't have any beamshots myself yet, but here are a few pics. I've just finished "modding" mine with LEDDNA 10 degree optics for a tighter beam on a helmet. The stock optics are frosted and I'd guess 15 degree. They've been measured to have significant light loss compared to the LEDDNA optics and others.

Optics swapped with white holders removed:

Stock optics (right) vs. LEDDNA 10º optics (left):

DX Mount (right), stock (left):

Optics holders trimmed to fit (to help reflect more light back out):

I had to trim the back side of the optic holder to get them to seat down far enough to get the faceplate to seal:

Final Light (yes, front o-rings pushed out a little - the LEDDNA optics don't have that nice indent for the o-rings to seat on):

Will have to update with beamshots. Sorry I won't have before & after though. In stock form the optics work great for bar use; a nice wide swath of light maintaining some decent throw.

EDIT - see post#45 below for beamshots.

-Garry

Nice info. Thanks for sharing. Really like the look of the host. Looks quite sturdy (not counting the mount). Sounds like the UI is very close to what you were seeking before that KD driver came out.

Thanks Garry.

How does it compare to the current “good” Yinding?

As it’s night riding season again, I’ve been making good use of my FrankenDale flashlights.

It's pretty much better than the Yinding all around. Better build quality, more mass for heat management, "off" out of the mode cycle, and a bit more output current (Yinding at 2.4A per LED IIRC). Apart from the BT70, Nitefighter is really producing great lights for really good prices. I'd easily pay $35 for just the lighthead.

Hmm . . . It seems I forgot to list my Yinding in this thread. I'll have to add that too soon.

-Garry

I see gearbest is out of stock for the BT21…

A good light?
I was wondering to snap it up, but no reviews had been posted. I guess I should have looked at MTBR
I’m not a modder so I would just use it as is.

Snagged a few beamshots of my BT21 with LEDDNA 10º optics last night. Same location as my other beamshots. I used 2 batteries at about 75% charge in my modded Fenix case (so Turbo may be a hair dimmer than max). Distance to the two trees is approx. 185 feet, approx. 275 feet to the house off to the left of the tree:

Low:


Med:


High:


Turbo:


My wooded setting:

Low:


Med:


High:


Turbo:


For comparison, here are mouseovers with the BT40s on Turbo (mouse out=BT40s, mouse over=BT21 (note: photos takes on different dates):




Might as well throw in some mouseovers with my modded HD-016 (mouse out=HD-016, mouse over=BT21 (note: photos takes on different dates):


-Garry

Modded my Nitefighter BT40S to the new Nichia 219C's. Here are some beamshots with mouseovers.

Mouse Out = Original Stock XP-G2's, Mouse Over = Nichia 219C's:

Wooded setting:

And wooded shots of the Nichia modded with the light mounted below the camera so as to get that darn bright button out of the photo! Low, Medium, High, then Turbo:

The yard shot doesn't show it too well, but in the wooded shot it appears that after the Nichia mod that the light lost just a tad bit of throw and gained a little more flood. The color rendering does in fact look better, even though it wasn't that bad with the original NW XP-G2's. (Look at that first large tree to the right.) I can say that those leaves and foliage look exactly like they do to my eyes in the daylight.

Next up, boosting the driver output higher.

-Garry

Quick comparison of my custom HD-016 (dual XM-L2 T5 5B1 emitters) vs. the Nichia modded BT40S.

(mouse out=HD-016, mouse over=BT40S Nichia Modded):

Hmm . . . I still like that 5B1 tint!

-Garry

Garry… I’m following your post for some time now. Enjoying it! Thanks for your effort! Great seeing the 219Cs in action.

Great info and pics. Thank you for all the hard work this all must have taken.

I initial impression was that you lost a little throw going to the 219C, but I think all the added flood and cooler tint threw me off. If you look at the dark area beyond the visible beam (first picture in Post 46), more items are visible in the 219C shot. Has something changed out in that area to make those objects better reflect light?

No, I don't believe anything has changed. I gave that first mouseover a good closeup look and they appear identical to me as far as what is visible in the distance.

-Garry

^

OK, I pulled up your pictures on a better monitor and I see what you mean. The throw is a little less with the 219C. What was throwing me off was the big dark trailer that was in front of the big structure or fence on the right and the house/building that is more visible on the right. I think that building is showing up more because it is now in the bigger flood of the 219C. On the better screen, I can see some stuff in the dark that I could not see with the 219C. Although the throw is slightly less, the bigger flood seems better for biking so that you can see objects approaching the path better further out.

Hi guys, long time no see.

I got a question on how to feed the ‘Kaidomain’s Gemini Duo / Yinding Clone’ when it’s 4.2V only?

I was thinking about a 2 cells parallel setup, but got problems to find a nice off the shelf battery case, most discussed cases are always 2s2p and therefore deliver to much voltage.

Garry how did you power up this nice budget bike light?
The price at kaidomain is really tempting.

Excellent work. Thanks for sharing. Very impressive. The colour rendition is superb.

I would recommend strongly against the 4.2v version. You get too much voltage drop through the thin wires. (See the thread I did on that light asking for help doing the sense resistor mod. I think it's linked further up in this thread.) I don't even use this light anymore. Buy the NW Yinding at GearBest. Much better light with great thermal path. Or the Nitefighter BT21 is an even better light.

-Garry

Thank you Garry !
I will follow your advice and look closer at the Yinding version at gearbest.

Since the nightride season in german mountain bike forum just started, I will probably get back to you (and everyone else in this part of the forum) with more stupid questions.
Though I’m still not unsatisfied with my Solarforce at the handlebar, I would like to get a bit ‘more’ or ‘better’, you know the old flashaholic virus……. sigh.

So I boosted my BT40S driver up to a calculated 4.0A (2A per emitter) and I think I might have this driver boosted for too much light (is there such a thing?).

Some details: I've replaced the SS34 diode with an SS54 (which is huge in comparison - didn't realize that). I also replaced the stock "2300" FET (datasheet found here) with an "AO3400" ("A09T" chip marking - datasheet here). I happened to have the AO3400's on-hand from my Courui mod. Lastly I added (2) R200's on top of the (2) stock R200's. I had already replaced the power cable with the DX 20 gauge one.

Driver with FET and diode replaced but prior to adding R200's:


Comparison of the SS54 to the SS34:

Fired up my driver-modded BT40S for a bench test. Started out at 3.3A from 2 fully charged protected cells in my modded Fenix 2 cell case. Left her burn-in and no smoke, no hot components either. After 2 minutes the lighthead was starting to get uncomfortable to hold in my hand. Wow it's A LOT of light!

This light will definitely need powered from my homemade 2S3P pack made from those Xiaomi power banks. (Need to finish that yet.)

Here are some beamshots using 4 fully charged unprotected cells in my old Pannova case. Current measured off the case was 3.48A peak dropping to about 3.2A (so Turbo would give more output yet if I can get a pack to provide the full 4A output. (Remember, these beamshots are with Nichia 219C LEDs.)

Boosted Driver:


Stock driver:


Boosted Driver:


Stock Driver:

Wooded Mouseover: Mouse Out = Stock Driver, Mouse Over = Boosted Driver both "Turbo" mode :

Yard Mouseover: Mouse Out = Stock Driver, Mouse Over = Boosted Driver both "Turbo" mode :

And here's how much more output low has now (it pulls about 1.0A on low for +/- 500mA per LED).

Boosted driver's "Low":


Stock Driver's "Low":

Mouseover on the "Low" mode, Out = Stock, Over = "Boosted Driver"

So what do you think? Should I lower output to bring Low-Med-High back down some? And any thoughts on why "Turbo" doesn't pull full calculated current? Even the stock driver was calculated at 2.0A but only pulled about 1.75A.

-Garry