Cost, obsolescence, and how much 'better' can lights get ?

[Diving Dubai]

My experience and involvement with LED lighting is with TV and Video lights. Obviously our challenges are different, we don't need them to go underwater, but we do need very accurate and consistent colour rendition - a camera will soon highlight if one light has a slight difference in colour temperature. We're now hitting as standard CRI greater than 96% where as 10 years ago 90% was just a dream
.
Obviously not all LED arrays are the same, or have similar quality, and dive light manufacturers aren't really at the cutting edge.

Ignoring the quality of LED, the main improvements are efficiency. Throwing more power at them is a waste of time, and actually reduces efficiency if you can't get rid of that heat, and they produce a lot of heat. Careful design of the lense and collimators not only shape but material is also of huge importance. I was amazed early on how much of an improvement we could get, without putting in more power or changing the arrays (in the region of 20% brightness output)

And yes as Tbone rightly points out, decent electronics to keep everything stable

I've put a couple of well known highly though of dive lights on our test bench for the giggles and they're pretty disappointing (in relation to what we'd expect to achieve with the same) So if the manufacturers improve their designs there's plenty more that can unlock.

Yes we did create a prototype for our own amusement and it was stunning, although it was more for our own engineering fun than a serious product - the markets too small and it's not our core business.

 

[kelemvor]

My experience and involvement with LED lighting is with TV and Video lights. Obviously our challenges are different, we don't need them to go underwater, but we do need very accurate and consistent colour rendition - a camera will soon highlight if one light has a slight difference in colour temperature. We're now hitting as standard CRI greater than 96% where as 10 years ago 90% was just a dream
.
Obviously not all LED arrays are the same, or have similar quality, and dive light manufacturers aren't really at the cutting edge.

Ignoring the quality of LED, the main improvements are efficiency. Throwing more power at them is a waste of time, and actually reduces efficiency if you can't get rid of that heat, and they produce a lot of heat. Careful design of the lense and collimators not only shape but material is also of huge importance. I was amazed early on how much of an improvement we could get, without putting in more power or changing the arrays (in the region of 20% brightness output)

And yes as Tbone rightly points out, decent electronics to keep everything stable

I've put a couple of well known highly though of dive lights on our test bench for the giggles and they're pretty disappointing (in relation to what we'd expect to achieve with the same) So if the manufacturers improve their designs there's plenty more that can unlock.

Yes we did create a prototype for our own amusement and it was stunning, although it was more for our own engineering fun than a serious product - the markets too small and it's not our core business.

Color is a great point. I am in the process of upgrading the LEDs in my home to high CRI bulbs. Expensive just to get to 95% considering I've got 48 standard bulbs in my house (not counting strip lights or converted florescent fixtures). When I started the upgrade I was just after flicker elimination.. but reading about it leads you down the CRI rabbit hole pretty quickly. There's a Chinese company that makes all kinds of 99% chips but they are out of my price range for sure. Things sure look nicer and kind of "feel" better with good lighting.

 

[tbone1004]

Color is a great point. I am in the process of upgrading the LEDs in my home to high CRI bulbs. Expensive just to get to 95% considering I've got 48 standard bulbs in my house (not counting strip lights or converted florescent fixtures). When I started the upgrade I was just after flicker elimination.. but reading about it leads you down the CRI rabbit hole pretty quickly. There's a Chinese company that makes all kinds of 99% chips but they are out of my price range for sure. Things sure look nicer and kind of "feel" better with good lighting.

have you or @Diving Dubai seen this article that @Bobby did?

https://uwlightdude.com/high-cri-best-of-both-worlds/

 

[O-ring]

Subscribed.. still diving an 18/9.

 

[stuartv]

The thing that doesn't seem like it has really been brought out in this thread is what lights maintain their output level over the discharge of the entire canister.

From what I know, the UWLD is the only one mentioned that does.

I gave a long, hard look at the DR EX35. But, it maintains constant output for only 1 hour and then starts gradually tapering down. That took it off my list.

I have not purchased yet, but the UWLD LD-40 is going to get my money. Constant light output, a bright and tight beam, and the modularity that will let me use the same can to run a light, a heated shirt, or both, with no muss and no fuss.

In fact, I will probably buy the battery can and heat controller before I get around to buying the light head. I already have the heated shirt.

 

[broncobowsher]

Stuart, I'm with you. That was my research as well. That EX35 looks like a deal. And if I was doing single tank recreational dives the limited hour of peak output would probably do me just fine. But the more I looked at my profiles, and even day to day logistics, I just didn't accept it.

After a LOT of research and even spending some time talking to Bobby, buy once, cry once. LD40 should be here by the end of the week. Enough reserve capacity in the battery I can do some heated underware in the future on the same battery. This is about as future proofed as I can foresee.

I did read up a little on the laser headlight technology. Really short, a laser blasts a Phosphorus substance and that glows, much like a flourscent bulb doesn't shine from the plasma arc inside but from the Phosphorous layer inside the glass that makes the light. So far it is only high beams in the cars. I don't think they have it down good enough to get a good beam pattern for low beam. Thus not going to make a good beam pattern for a dive light. at least for now. In a decade or two it will probably be the next hot ticket. By then it might be time for a new light.

 

[wetb4igetinthewater]

Technological improves always become more gradual over time. How much more efficient can LED and the circuitry driving them become? I've seen a number of just over 300 lumens per watt as possible, but most are in the 200 lumens per watt range. I'm not in the business, so I can't speak to this authoritatively. I'd leave that to @tbone1004 or @Bobby.

At this point in time, when I get into cave diving, my choice will be an UWLD offering.

 

[Addison Snyder]

The thing that doesn't seem like it has really been brought out in this thread is what lights maintain their output level over the discharge of the entire canister.

From what I know, the UWLD is the only one mentioned that does.

source

So confirming my assumptions, the voltage-lumen relationship (making a bad-ish assumption that amperage is directly linked to light output) has a pretty strong curve. So if you have a light that claims to keep a constant lumen output throughout the battery's charge, then one or more of the following should be true:

A) the light isn't using the batteries full capacity (stops operating to avoid the bottom of the amperage curve)
B) the light isn't using the full advantage of the upper end of the amperage curve (limiting the brightness and artificially flattening the top of the curve)
C) oscillating (highly doubt, but a possibility I guess)

In short, unless long-ish video and maintaining constant brightness is your number one goal with the light, you're gonna have some compromises in brightness/duration. That explains why the EX35 doesn't maintain perfect brightness over time. The maker of the light thought, "ok, he's got perfect brightness but the voltage is running low, now we can turn it off on him or compromise that perfection - I'm guessing he wants the latter in a cave". I haven't looked at the UWLD one much, and am curious about that claim and how he does it.

NOTE: It's been a long time since I knew much about electronic circuitry and stuffs, might easily be on top of Mount Stupid here. Let me know if I'm wrong here.

 

[tbone1004]

@Addison Snyder
If pack voltage is considerably higher than the voltage required by the LED and a buck driver is used to maintain a constant voltage output across the voltage swing of the battery pack, then constant output can be maintained. If however pack voltage is being fed directly, then as voltage sags as a function of battery capacity, then so will output.

 

[stuartv]

In short, unless long-ish video and maintaining constant brightness is your number one goal with the light, you're gonna have some compromises in brightness/duration. That explains why the EX35 doesn't maintain perfect brightness over time. The maker of the light thought, "ok, he's got perfect brightness but the voltage is running low, now we can turn it off on him or compromise that perfection - I'm guessing he wants the latter in a cave". I haven't looked at the UWLD one much, and am curious about that claim and how he does it.

NOTE: It's been a long time since I knew much about electronic circuitry and stuffs, might easily be on top of Mount Stupid here. Let me know if I'm wrong here.

The EX35 maintains constant output (on High) for 1 hour, then starts tapering down over the next 5 hours (IIRC) until it gets to 10% of battery capacity.

My thought is, if (say) 50% brightness is okay at Hour 3, then why isn't it okay during Hour 1? In which case, why do I need a light that bright? Why not just spend less and get a light that is half as bright as the EX35 (on High)?

If I have decided that I feel a need to have a 4000 lumen light, then (to ME) it only makes sense to buy a light that can provide 4000 lumens at any time during my dive. Not only during the first hour.

For what even an EX35 costs ('cause it still ain't cheap!), I am definitely in the "buy once, cry once" camp on this. And the fact that after I cry once, I can buy just a heat controller and use the same battery canister to also run my heated undies just makes the initial crying that much more tolerable.