Feedback on DIY 10,000 lumen dive video lights

[Michael A]

Hello,

Please excuse that this is my first post, I’ve been lurking for several months now. I got into diving a couple years ago and have been enjoying taking video with a GoPro and some small lights. I’ve been wanting to upgrade my rig and as an engineer decided that a fun project would be to build a set of my own video lights!

My initial prototype design is pretty much complete and I wanted to get feedback from the diving community. I’d be really interested in reading comments on what features divers like and don’t like about the lights. What additional features would you like to see? Would this be something that you would want? How do you think they compare to what’s already out there? What lights do you currently use? How do you like them? I’d be happy to answer any detailed questions that you may have.

There are three light head options, 10,000 lumen white, 7,500 lumen white and 14W blue. I wanted to keep the size on the smaller side so that the overall rig remains manageable. The lights are driven with a closed loop constant current control system so that the brightness and lumen rating remains the same throughout the dive at any setting. A lot of the cheaper ones without this circuitry will dim quickly as you use them and only meet the stated lumen rating for the first couple minutes. I’ve put together a detailed spec listed of expected performance of my design below as well.

I’m building a set of 6-10 of these first prototype version for myself and some dive-buddies currently. I’d be up for refining the design based on usage experience and feedback and doing a small production run. I already have a list of things I’d like to include in the Rev02 version. I’d expect to be able to offer it for around $700ea depending on the scale of the run.

Dive Safe!

-Michael

Prototype Dive Light Specifications

Expected Depth Rating: 45m/150ft
Battery: 4x26650 Li-ion pack, 4S 4500mAH
Dimensions: L=116mm x W-90mm x H=110mm
Construction: Anodized Aluminum covers, Acrylic Body, 316 Stainless Steel hardware
Interface: Single Magnetic Hall Effect Slide Switch
Mounting: ¼-20” Bolt hole for 1” Ball adapter
Settings: 25%, 50%, 75%, 100% (firmware customizable programmable levels)
Control circuitry: Closed loop constant current circuitry
Protection: Thermal protection shutoff, Battery low voltage shutoff


Lighting Head Options:

7,500 Lumen white LED output
Device: 1x CREE CXA2540 COB LED
Beam Width: 115°
Expected Run Time:
100%: 1.0 hour
75%: 1.6 hour
50%: 2.7 hour
25% 6.1 hour
Color Temperature: 5000K

10,000 Lumen white LED output
Device: 1x CREE CXA3070 COB LED
Beam Width: 115°
Expected Run Time:
100%: 45 minutes
75%: 70 minutes
50%: 1.8 hours
25%: 3.6 hours
Color Temperature: 5000K


14 Watt Blue LED output
Device: 9x CREE XT-E
Beam Width: 140°
Expected Run Time:
100%: 1.5 hours
75%: 2.5 hours
50%: 4 hours
25%: 9 hours
Wavelength: 455nm



Possible changes/additional features for Rev02:
Battery level indicator, 4-level
Finer incremental adjustment (1% increments)
Better user interface button/switch/slide
Anodized Aluminum Body or Polycarbonate Body
Modify body to accommodate 6s, 4500mAh battery pack in same form factor
Double length for 4s2p or 6s2p battery setup
More protection for the front lens piece

 

[tbone1004]

I would look at using 18650's vs 26650's to get a bit better space efficiency as well as ability to use some standard off the shelf packs. Go to a 5s pack using the 3.4ah cells and you'll get roughly the same wh out of the pack, but be a bit smaller form factor wise

 

[Michael A]

I would look at using 18650's vs 26650's to get a bit better space efficiency as well as ability to use some standard off the shelf packs. Go to a 5s pack using the 3.4ah cells and you'll get roughly the same wh out of the pack, but be a bit smaller form factor wise

That's a good point, I was originally using 26650's as that's what my current lights use. It looks like i'd be able to squeeze in 8 of them in my current casing which is driven by an off-the-shelf part. Likely would put them in a 4s2p formation to stay only in boost and not need to buck. Should be able to get legit 3Ah ones so it would increase the overall capacity by 33%! Would need to charge as a pack with sense leads though to make sure the two halves stay balanced. What's nice about just having 4s is you can take the cells out and charge them individually and put them back together but 33% is really significant amount of time especially for max power hitting the 1 hour sweet spot.

 

[3D diver]

Run time is too short. I need 2-2.5 hours for the diving I do.

 

[Michael A]

Run time is too short. I need 2-2.5 hours for the diving I do.

Good to know, thanks for the input! Is this because you are doing one long 2-2.5 hour dive? or don't want to deal with swapping out batteries between dives? Based on my own experience rec diving I wanted to keep them smaller to make them easier to mange while diving. But it's definitely a hassle to have to swap batteries when your'e dripping wet between dives. I have considered doubling the battery pack that could actually get to the 2-hour range utilizing 18650's from above but would want to understand the use cases.

 

[tursiops]

At the beam widths you are talking about, this is a video light, not a diving light. So, it is not needed for the entire duration of a 2+h dive. In fact, it really only needs to be a bit longer than the record-duration of your memory card. A dive light doesn't need to be that bright (unless e.g. cave-diving) and 10 degree beams are desirable.

 

[tbone1004]

a lot of us will use our video lights to record the entirety of a cave dive though, but it would be rare circumstances indeed where we could actually leave a 10k lumen light on for the duration of the dive. They usually get kicked down most of the time due to backscatter and/or size of the passage. I don't believe there is any light on the market that can do 10k lumen for much more than an hour on continuous burn. The battery packs get excessively large and expensive if you need that. That said, a 4s2p pack should go for about 40 minutes on high and if he has something like a 50% output setting, that should get you to the 2.5 hour mark

 

[3D diver]

My dives can run up to 90 minutes, so 2+ hours provides a good safety margin. For night dives add another half an hour, or more, for the surface swim.

I'm not saying I wouldn't take advantage of lower power settings, but wouldn't take lights with me I couldn't count on to last the whole dive + surface swims. I have enough task loading dealing with my cameras.

 

[Michael A]

My dives can run up to 90 minutes, so 2+ hours provides a good safety margin. For night dives add another half an hour, or more, for the surface swim.

I'm not saying I wouldn't take advantage of lower power settings, but wouldn't take lights with me I couldn't count on to last the whole dive + surface swims. I have enough task loading dealing with my cameras.

Thanks for the perspective! I definitely understand not wanting to have to worry about battery management for any of your gear. The confidence that they will last throughout your dive no matter how you end up using them on that dive is important. I really only have experience recreational diving and so had thought 1 hour would be a good sweet spot. The perspective of tech and cave divers is enlightening. Once I have a set built I'll be sure to run duration tests at the various settings and update with real performance.

 

[tbone1004]

there is not currently a video light on the market that is capable of those burn times with that much light output. If you are able to get 110l/w out of those lights it would be very impressive and more efficient than anything on the market today, but without a seriously big battery pack in there you aren't going to get that much output for that long in a reasonable size. Certainly not keeping it neutrally buoyant.

also, make sure you have a temperature cutoff sensor in there that will knock it down to low. These things produce an insane amount of heat when they're putting out that much light and if you have guys doing stupid sh!t like half hour surface swims with them on high, you need them to protect themselves from overheating.