Ultrafire DV-S9 diving light?

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Boro
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flydiver wrote:
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.

Dive vacations are the best!

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

Lightbringer
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Jerommel wrote:
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.

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.

Jerommel wrote:
Can you try shining it on a black fabric and listen? I bet it’s audible…
Hmm, what would that do?

Jerommel wrote:
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.

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.

Jerommel wrote:
Thanks for the review, Lightbringer.
No worries. Nice light…

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Lightbringer
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flydiver wrote:
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.

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Macka17
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Location: Queensland Australia

I bought an “Elfeland triple L6. 2 × 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.

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