Ultrafire DV-S9 diving light?

Diving lights can also be used to pick up divers from the surface if they get caught in a current and drift away from their dive site. Sounds like a good idea to me.

Did a 31 dive vacation (Lembeh, Indonesia) beginning of the month. The DV-S9 worked without a problem going to 90+ feet a few times. The only unexpected issue was the magnet is embedded in the black slider. This was a sandy area (muck diving for weird critters) and the light would often rest on the bottom during during photos. It picked up iron grit. Didn’t affect use in any way. I didn’t even notice it until I got home and was cleaning things up thoroughly. I was able to remove it with small strips of tape and finished with high pressure air.

I did notice some minor fogging in the lens with use. There were a couple micro-drops on the lens. There was no evidence at all of flooding from the front or back. I think it was condensation, probably during assembly. Removed the front lens. The red rig holding the lens in has a silicone O-ring and there is a main O-ring under the lens. It’s been fine on extended dunk tests but has not gotten a dive test since the disassembly.

90’? Yeesh, think my eardrums would pop.

Good to know it holds up to that kind of pressure, though! So it’s definitely safe for me to use whilst changing a tire in the rain, then. :laughing:

You forget to mention a very important point about this particular light you show.
The light you show uses the tail cap as a switch.
So when you’re under water and it’s switched off, there’s a potential difference between the tail cap and the body, and THAT’s what causes electrolyses.
There is no electrolyses when the tail cap is in the “ON” position, because then the parts connect shorting the potential difference between tube and tail.

I’ve been ogling these slider diving lights for some years now, but i have never seen a review that answers the PWM question.
So, this one uses PWM (i guess they all do because it seems to be cheaper), and it’s reasonably high frequency PWM.
Can you try shining it on a black fabric and listen?
I bet it’s audible…

I really like the concept of a slider dimmer, but it’s often implemented quite crappily…
The travel of the slider is often very short too, but maybe that’s no problem.

Thanks for the review, Lightbringer.

That would make it a poor backup light if this is a problem. If it’s screwed down and on there should not be a problem, right? I have not had this particular issue.

Dive vacations are the best!

Some dive lights headed my way, will report after use.

I’m not the one to ask, as unless it’s 120Hz flicker from mains-driven LED nightlights or the like, I have a hard time discerning PWM.

Ironic, as 120Hz flicker from old-timey fluorscent tubes gives me migraines.

Hmm, what would that do?

Pretty much has to be, as falloff over distance is 1/d², and there’s already part of the Al tube between magnet and sensor.

I don’t have much of a problem giving it little shoves brighter/dimmer. This is maybe a cm or so.

No worries. Nice light…

Even screwed-down and off there’s still a solid electrical connection, so no electrolysis. Everything’s controlled by the e-switch (slider), and the whole case is at ground potential.

I bought an “Elfeland triple L6. 2 x 18650 cell Magn sw.
For use on boat NOT diving.

It’s lived on boat ever since. (The tools IN my garage round here go rusty)
and still nice and shiny.
Nice beam comfortable in hand. Cost around $16/17 AUD.
Still for sale at EBAY for 13.09 UK pounds del.

Some of mates use theirs for diving on pots etc. (12 to 18ft)
They reckon it fine for that.

More should have that magnetic. Variable or not, switch.
There’d be a lot less problems there hey.
This one has dual O-Rings right through.

I bought the Ultrafire DV-S9 from https://www.ultrafire.com. I really hate the angry blue led. It’s is also not that bright and there is no way to replace the led.
The lens retainment ring is secured with silicone. Not sure what I will do with the flashlight. I’m in the mood of torture testing it.

Mine wasn’t Angry Blue™. Cool at about the usual 6500K, but not colder.

Maybe you just lost the Tint Lottery…

You are right the led it isn’t angry blue. To me everything over 5000k is angry blue because I like warmer color so much. But color is really subjective and depending on what you are normally exposed to.
Have you ever tried those 3d glasses with red and cyan color filters ? After taking of the glasses you perceive colors differed per eye. It’s a pretty cool effect.

It’s a DIVE light. Water absorbs the warm spectrum at a much high level than the blues. Cooler wave lengths tend to penetrate better in water.

Mmm, I could see The Void when I wear ’em.

Angry Blue by definition starts at 5,793.34 Kelvin and continues until Murder Blue which starts at 5,793.35 Kelvin.

Most people murdered while using a light are above the Angry Blue number, and most people beaten are between the Angry Blue and Murder Blue ranges.

(This is according tho the latest FBI statistics.)

Just a comment:

I also tried the Ultrafire DV-S9 when it was on sale in Gearbest quite some time ago. A friend also wanted to get one but it wasn’t on stock in Gearbest anymore so I ordered one for him from ultrafire.com too.

What I noticed: the LED of the earlier DV-S9 from GB looks like an XM-L2 (I can’t verify if it’s genuine or not, but it looks similar to the genuine XM-L2 on the Convoy S2+). But the LED from ultrafire.com DV-S9 doesn’t look like a genuine XM-L2. (genuine XM-L2, dots are in alternate pattern; the “non-genuine” XM-L2 LED is in straight pattern).

Regarding lower brightness — I’ve noticed that when the magnetic slider is on the max position, it still doesn’t reach highest brightness (if I use my “shine light thru portable fan” method, there will be some PWM noticeable). However, if I place a magnet on the top of the slider’s max position, then the DV-S9 light will become noticeably brighter - and using the “shine light thru small portable fan” method, there is No PWM when on max output — meaning it has reached its max brightness).

The same (place magnet on DV-S9 slider) is actually true for the DV-S9 from GB and DV-S9 from ultrafire.com. The GB DV-S9 seems to be just slightly brighter on max than the ultrafire.com DV-S9 on max (probably due to use of the XM-L2 clone LED)…

An advantage is that with lower brightness (magnetic slider not really reaching max brightness), is it draws less current, and consequently will have longer runtime.

That’s something new to me (“cooler wave lengths penetrate better in water”).

I’m curious then: Sofirn’s SD02A diving flashlight uses a warm 3000K tint (I notice most other budget flashlights labeled as “diving” light often just use the default cool-white, with some seem to be closer to “angry blue”) — so is there any advantage for warm tint on water? or it’s not really a good choice done by Sofirn?

Depends on the dive location, and the diver visual goal. The red spectrum disappears first underwater. That’s why water is blue, It’s the only color that comes ‘back out’.
If the water is clear, and it’s important for you to SEE the reds, then a warm light may be the ticket. At 100 feet pretty much everything looks pretty gray without light.
OTOH, if you are in cold green water, with poor visibility (like I am), then penetration and signalling might be a more important consideration. The underwater landscape is not as pretty anyway so fussing about minor color shift is not such a big deal.

Photography, either still or video, adds additional complexity to this decision.

Huh… interesting! Never even though to test “external turbo” with another magnet. :laughing:

Didn’t even compare the ones I got to compare LEDs.

I must be very complacent.