26650 Diving light test

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Werner's picture
Last seen: 2 years 3 weeks ago
Joined: 10/19/2012 - 15:00
Posts: 3679
Location: Germany
26650 Diving light test

Eachbuyer gave me this light.
Its a diving light which runs with a 26650 and has a modeselection ring. It is kind of a “26650 C8” which made it interesting for me. There are some different versions around, which all are a bit different in pill design and overall quality there are also some other reviews of these similiar lights on the forum…
Now over to my findings of this exemplar:
The kit came with a charger, a uk adapter,a 18650 sleeve and a Ultrofite 18650:

Two orings on each side:

The head Diameter is 53mm, the total length is 150mm. tube diameter is 30mm

Ultrofite 4200 mAh tested at around 850mAh:

It says protected but I am not sure of this, I will find out after discharging and before tossing…

I dont like these cheap chargers and I haven’t tested it entirely because of safety reasons, but it works and it has a indicator LED. The slide length is long enough even for 70mm batteries, so this maybe find another life as a charging cradle.

I made a comparison Photo showing it to a X8 and a C8, the size is very comfortable for use…like I said above its a thicker C8…

The light itself has a poor, flaky anodizing in grey. Especially the head has some lighter grey spots and the tailcap edge is rough and has some defects. It came with dirt on the threads and lens. I would rate this as normal for a budget light so no biggie for me.

Light output
In stock form with the ultrofite it makes around 300lm and 1.7A
On a Samsung20R it makes around 400 lm at 3.3A Shocked
Of course this is due to bad thermal design and the huge plastic ring around the LED. I did a short throw test at 2m and I could easily get around 3000-4000 lux so throw is C8 niveau(what a suprise…)
I played around some days with this light and the ultrofite battery inside and showed it to other people and the overall conclusion was that the form and function is good. Of course the lightoutput is poor in our eyes but it works well enough because of the tight hotspot and good throw.
The UI is simple:
the Selector ring has three positions: On OFF Disco
If you now twist from off to the left it starts in High, if you go back to off and after that to on again it switches in med mode….
Its simple but works very good, with 4 different brightnesses
On the right side this has 4 different blinky modes SOS, 1Hz Strobe, 3Hz strobe and 9Hz strobe
No memory so you can always start in high with a quarter twist.
Standby current is low and the light can be locked out via tailcap

Then I made me some thoughts about testing its waterproofness and decided to do a quick test in a waterbowl:

The result after short time(maybe 2 hours) was disapointing, there was water inside the head on the lens:

I opened and dried and investigated the reason:
You can see the dissassembled head here:
bezel, 47mmx2.6mm plastic lens, C8 SMO reflector, and head with large O-ring:

Normal setup which should have let no water inside…right?
No definitive wrong build:

You can clearly see that the Reflector is higher than the oring because the oring is not laying on a plain surface its in a groove and doesnt makes contact/seal to the lens…
Picture of the problem/groove:

I guess if I would fill up the groove with something, maybe a thick wire, glue or whatever, the oring would be thick enough to be higher than the reflector and seal it up…

Pill and driver design
Now over to the Pill. There are versions with a pill and reflector screwed together and making poor contact to the head this one is different.

20mm Star and 20mm driver.

From battery side there is a retaining ring which can be screwed out easily. The driver has two magnetic sensors for the different positions of the selector ring. The driver and LED sit inside what looks like a hollow pill, but I wasn’t able to unscrew it yet.
The driver looks very simple, just some voltagedividers for batterymonitoring, magneticsensors for modes and a controller which drives a FET with PWM.
It could be modded with a tiny to other modeselction but I dont see much better possibilities with these two positions, from off to the left it always starts in high with the option to use a lot o other modes if needed I find this good. The Fet gives a lot of Amps so onresistance is good too…

nice form factor->C8 reflector, 26650 capable
selector ring
8 modes: high, med, low, lower low along with SOS,and 1Hz,3Hz and 9Hz beacon/strobe
works good with the parts provided in the kit
Standby current is low and the light can additionally locked out via tailcap
a classic budget light with lots of small lacks with some serious modding necessary to achieve convoy C8 level->fill out hollow pill, close groove for oring along with the standard mods
I am no fan of the ultrafire ultrofite batterys and cheap chargers
not waterproof diving light is very paradox

Edited by: Werner on 10/27/2014 - 12:37
fellfromtree's picture
Last seen: 6 years 11 months ago
Joined: 07/25/2014 - 15:14
Posts: 470
Location: spelunking

Wait a diving light that’s not waterproof. Maybe it was missing a extra O ring in the head? The magnetic ring is interesting but I don’t like that pill either.

I’m looking for a cheap light with a magnetic ring and good throw to mod for a coyote light. Red and UV basically. If I can squeeze in green and white that would be awesome too. Going to use that 4 color LED Smile At least in my mind it’s all going to work- but you know how that goes

Werner's picture
Last seen: 2 years 3 weeks ago
Joined: 10/19/2012 - 15:00
Posts: 3679
Location: Germany

I could try to add a thick black oring from plumbers accessory on top of the green one if I have the correct size but I don’t think that there is something missing by accident its just a bad design. I also tried the light without the big white LED centering but it didn’t get any better…

Wasnt CK modding some of the selector ring lights, the rooks or so…?

Last seen: 2 hours 3 min ago
Joined: 06/19/2013 - 19:16
Posts: 1296
Location: Seattle, WA

I have 2 of those lights (different sources) and a buddy with another couple. All are made a bit differently, none are great, all have been waterproof to actual scuba depths…..so far. :8)
Without being able to see that particular arrangement of head/bezel O-ring I can say it looks like a ‘normal’ setup. The threads are crude, not lubed, and it needs some TLC to seal right. It takes very little to create a leak underwater. It’s quite possible your particular unit could be made poorly.
As discussed in other threads the magnetic switch uses a low carbon spring and ball bearing that WILL rust out if used in water, much faster in saltwater.
Pill thermal path seems to be quite variable in different models, along with the sealing O-ring arrangements.

For a cheapy I was impressed how well it works even compared to commercial $450 scuba lights. OTOH, I trust those. This light I expect to die every time I use it. The quality just isn’t there. Saltwater and extreme pressure will make a mockery of poor design for sure, sometime.

To Air is Human, to Respire….Divine.

Werner's picture
Last seen: 2 years 3 weeks ago
Joined: 10/19/2012 - 15:00
Posts: 3679
Location: Germany

If you find some time please check how your oring design is made…I guess you don’t have that groove or your reflector is shorter…
This design with oring under lens works better if it’s deeper if I understand that correct so my bowl experiment might look worse than it would be under real circumstances…but on the other side it can’t be watertight if the reflector is the highest point anyway…

What is TLC?

Last seen: 2 hours 3 min ago
Joined: 06/19/2013 - 19:16
Posts: 1296
Location: Seattle, WA

tender loving care.
Actually in Hawaii diving now so it’ll be a week before I can get back to you on that.

If you get a dog hair across the O-ring, or any other inconsistency of sealing it will leak under scuba level pressure. I’ve leaked a number of carefully assembled camera cases :_( that proved to just fine on the next test dive.

To Air is Human, to Respire….Divine.

djozz's picture
Last seen: 5 hours 55 min ago
Joined: 09/07/2012 - 17:04
Posts: 17994
Location: Amsterdam

Thanks for the review, and the responses.

I have that light as well, it is very flimsy made but I can not find a good reason why it would not work as a diving light except that same seal. My o-ring sits a tiny bit higher than yours, but it will still not seal great I guess. If you dedome the emitter and remove/sand-flatter the centering ring, the reflector will sit deeper (but then it may rattle and not press the ledboard down, it is all a bit subtle with this light...).

Last seen: 4 weeks 1 day ago
Joined: 06/30/2012 - 18:12
Posts: 107
Location: Israel

I have a similar light to your.

I did some modifications before diving:

1. I changed the driver into 10*7135 [105c] with a custom firmware [1-mode only], and added a reed switch for the magnetic control.
2. I didn’t find any better way to make a good heat dissipation, so I filled the gap with goot wick copper, and thermal paste – now the Aluminum head is getting HOT in seconds – so it is nice.
3. I added a third o-ring on the taicap to make it more waterproof
4. I added A LOT of silicone paste on the head, and sanded the plastic ring to lower the reflector – now it sits very tight and nice
5. changes the led to XM-L2 4c [ yelow light], as I usually use it for spearfishing in day-time, so a a yellow color is better seen in such conditions

finally, I’m quiet happy with this light – after all those modifications….
I dove with it for 2-3 months already up to 50ft (salt water), it was nice and didn’t leak at all.
About the battery, I like to use it with Trusfire [FLAME] 26650 4000mah or LG 18650D1 4.35V which is better for 7135 drivers.

Hope I could help someone, have a nice diving! Party