I just received a DV-S9 from FT - under $18 with BLF code, and i’m impressed.
Very nice 26650 light with magnetic switch for the price. Although it’s not a top performer it seems, i especially like the slider smooth operation…. I lubed the tail cap and o-rings while loading a 26650.
Not sure when/if i will have a chance to use it underwater. I got it as a backup to a (still unused) Solarstorm DX4. :person_facepalming:
PS: thanks to the above comments about the red ring preventing the switch to fall off. Mine was loose and i wasn’t sure what this ring was about nor did i noticed it would actually screw in. I would probably have lost the slider at some point. :+1:
I don’t know how to test this but I believe the flashlight has a rather high parasitic drain. I left a battery in there unused for several weeks (< 1 month), and the battery was drained to below 2V when I tried to use the flashlight. As this isn’t a flashlight I would use once every week, I don’t leave battery in there anymore till I want to use it.
Even when “off”, the Hall-effect circuit for the slider draws something like 10mA. I mentioned it somewhere in this thread, so I think that’s how much it was. Not at all unusual or unreasonable. But yeah, I always gave the beastie a quarter-turn lockout when not in use.
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.
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.
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.
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.
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.
