[Review] Wurkkos DL40 - 4x LH351D Dive Light

11 posts / 0 new
Last post
gchart
gchart's picture
Offline
Last seen: 1 hour 48 min ago
Joined: 03/19/2016 - 11:57
Posts: 2228
Location: Central IL
[Review] Wurkkos DL40 - 4x LH351D Dive Light

The Wurkkos DL40 is a new Dive Light. I’ll be up-front about this (as I was with Wurkkos, who kindly provided this light for review) – I’m not a diver, nor do I currently have access to a deep body of water. That said, I feel like the DL40 is a nice light even above the water.

What I like:

  • This thing is bright! Especially for the first few minutes.
  • Great LEDs: 4 of the 5000K, 90CRI LH351D – lots of lumens and high CRI
  • Solidly built – double o-rings on each end of the tube, nice threads. Has a nice heft to it.
  • Full kit: 2× 5000mAh batteries, charger, lanyard, etc
  • Low standby drain: 47uA
  • Even after the ramp down, it maintains ~2000 lumens
  • Ran for 3 hours before dropping off
  • Nicely focused beam (which can have an interesting flower shape up-close)
  • Reportedly has temperature regulation (“ATR”) – I’m still verifying this. From Wurkkos: “Advanced Temperature Regulation (ATR) technology, avoid the light overheating when the the driver temperature reaches 50℃”

What could be better:

  • If you need a low mode, this really isn’t your light. I have a feeling that most divers probably don’t need a proper moonlight mode though.
  • Upon receipt, the tailcap was not attached to the light and the battery separating disk had gotten lodged in the tail spring. While trying to remove disk, the spring popped out. After a bit of work, I was able to get it wedged back in.
  • One battery seems stronger than the other. When I initially charged them, one had a higher voltage. After using the flashlight a bit and then going to top off, one battery again had a higher charge. And after the runtime test, I checked the voltage (after they rested a while) and one was at 3.08v while the other was at 3.33v.
  • Bezel appears to be glued (which is probably good if you actually dive with this thing)

Brightness Levels: measured (spec):

  • Level 1: 407 lm (300 lm)
  • Level 2: 1180 lm (820 lm)
  • Level 3: 2859 lm (2000 lm)
  • Level 4: 7223 lm (5000 lm)
  • Note: my lumen tube is not calibrated and may report slightly high

Note: this reflector appears to be near-identical to the Q8, but perhaps a bit deeper

Left to right: Wurkkos DL40, WK30, and FC11… all very nice lights

Double o-rings and anodized at both ends of the tube

About 2 feet from the ceiling, the flower shape is visible

Backed up to 3-4 feet from the ceiling, beam smooths out

Approximate Lumens vs Runtime with Temperature – first 5 minute (no cooling)

Approximate Lumens vs Runtime with Temperature – full run (no cooling)

Note: I plan on submerging the light for a while in a bucket of water and measuring lumens periodically (to verify that ATR is indeed working properly and that the ramp-down wasn’t timed)

Edited by: gchart on 04/09/2020 - 00:31
gchart
gchart's picture
Offline
Last seen: 1 hour 48 min ago
Joined: 03/19/2016 - 11:57
Posts: 2228
Location: Central IL

The submerged runtime test looks reasonable. I decided that instead of using a bucket, I would put it in a gallon ziplock bag of water. That way I could still automate the measurements and set intervals.

So, it still ramped down, but it did so at 10 minutes instead of 1 minute. The water was still around 28°C so I’m guessing maybe it had a 10 minute timer in addition to temperature regulation? Or perhaps the driver isn’t shedding heat to the body optimally? I’m not 100% sure what to make of it. Either way, 10 minutes of ~5000 lumens doesn’t seem too bad.

SKV89
Offline
Last seen: 2 hours 57 min ago
Joined: 12/10/2017 - 12:46
Posts: 3832
Location: US

Thanks for the review. But I think theres something not right with the lumen measurements. 4xLh351D 90CRI would not be able to achieve anywhere near 7000+ lumens.

gchart
gchart's picture
Offline
Last seen: 1 hour 48 min ago
Joined: 03/19/2016 - 11:57
Posts: 2228
Location: Central IL

I don’t doubt that these numbers are a little elevated, my lumen tube has not been calibrated. And I’ve never really attempted to measure a light this bright. Perhaps an amp draw reading might help figure out what Turbo is doing.

gchart
gchart's picture
Offline
Last seen: 1 hour 48 min ago
Joined: 03/19/2016 - 11:57
Posts: 2228
Location: Central IL

Update: I just checked the amps on turbo using fresh batteries and a clamp meter. I got ~8.75 amps at ~8.4 volts (I didn’t measure voltage, but they were fresh off the charger). So that’s 73.5 watts of power. If each LED got 1/4 of that, 18.375 watts per LED.

Strangely, I can’t find much in terms of output tests of the 90-CRI version of the LH351D. In Texas_Ace’s test of the 70-CRI version, that would translate into approx. 1800 lumens per LED for a total of 7200. Of course, being the 90-CRI version, output will be lower.

Well, I just found maukka’s output test buried in a thread. He notes that he suspected his reflow might not have been the best as his output tapered off unexpected early. Nonetheless, his test showed ~1300 lumens at that wattage. So that’s a total of 5200 lumens at worst-case scenario.

gchart
gchart's picture
Offline
Last seen: 1 hour 48 min ago
Joined: 03/19/2016 - 11:57
Posts: 2228
Location: Central IL

Wurkkos requested if I could do a little video of the DL40. It’s cold and wet – so it’s short indeed! And perhaps a bit rushed & unrehearsed. That’s real life, folks.

Yes, I said “Sss…Wurkkos” – I started out saying Sofirn. Oops!

Boro
Offline
Last seen: 1 hour 57 min ago
Joined: 02/03/2012 - 15:52
Posts: 652
gchart wrote:
[reserved for bucket / water-cooled output test]

Looking forward to your test; this light has promise.

Temperature regulation, tint and beam pattern would work well diving.

gchart
gchart's picture
Offline
Last seen: 1 hour 48 min ago
Joined: 03/19/2016 - 11:57
Posts: 2228
Location: Central IL

Thanks for the reminder! I just ran the test and added it to the second post.

prototype3a
Offline
Last seen: 1 week 5 days ago
Joined: 12/19/2018 - 20:06
Posts: 270
Location: Christiansburg, VA

I guess this is a 2× 26650 light?

gchart
gchart's picture
Offline
Last seen: 1 hour 48 min ago
Joined: 03/19/2016 - 11:57
Posts: 2228
Location: Central IL

Shoot, I guess I didn’t mention that. Yup, 2× 26650. Also comes with sleeves for 18650 compatibility.

MacLee
Offline
Last seen: 13 hours 6 min ago
Joined: 05/28/2019 - 05:14
Posts: 54

+1