Dive Rite EX35 - Awesome?

[stuartv]

I love the DR lights from the past few years, ever since the LX20, they have been making extremely good lights at a really good price. That's not to say UWLD or LM are bad at all, I really think you can't go wrong with any of the lights from the cave country manufacturers.

The EX35 is a hell of a light. I like the sexy head design with the red fins and the black outer casing, and the physical switch which is a little more affirmative than a piezo. It's not fair to state that it "tapes to 1% over 5 hours," better to say "Tapers to 20% over 6 hours then remains an emergency light source for an additional 16 hours."

Assuming the UWLD are truly a consistent 3500 lumens over the burn time, you have the option of
-1.5 hours for $1,545
-3.3 hours for $1,745
-5 hours for $1,945

The EX35 starts at 4300 lumens, 22% more than the UWLD, and stays above 3,500 lumens until hour 3, making it essentially the same as an UWLD with a Short battery, but at $1,200 instead of $1,745, so not only it is 31% cheaper but it continues to function for an additional 3 hours after the UWLD would have shut off.

I think most of us have an older light body which could be repurposed for suit heating, which is beyond most of us as well, so I don't think the stacking caps should be high on your list of must haves. I'm sure you'll be happy with both lights, but the EX35 will not disappoint. Don't read into the "tapers down," all LED's have some degree of tapering as they heat up and limit the current, and I've never been in a situation where I noticed the EX35 tapering down to a point where it doesn't feel like the brightest MF'er in the room. That said, I love my HP50 but for dives over an hour, the EX35 has significant gains on burn time and my original HP50 batteries are slowing down a bit, so if you have the money for an EX35 I would not second guess or waste a moment, order it!

The EX35 is down to 3500 after 2 hours and dropping steadily from there.

If that works for you, fine. I’m not knocking it. I’m simply stating what the specs are, and that it’s not how I feel like I should invest my money. The OP should have the facts and make their own decision about their budget and what works for them.

 

[taimen]

Considering buying one. Any reasons not to or to buy a different can light?

It doesn't have a groove for tying a bungee loop into the back end of the lighthead. This may or may not be important for you if you prefer tail clipping your light.

 

[Caveeagle]

The EX35 starts at 4300 lumens, 22% more than the UWLD, and stays above 3,500 lumens until hour 3, making it essentially the same as an UWLD with a Short battery, but at $1,200 instead of $1,745, so not only it is 31% cheaper but it continues to function for an additional 3 hours after the UWLD would have shut off.

Probably my only criticism of the EX35, is that I wish it stepped from 100% down to 75%, then 50... that way I could start off my Dive better matched to some of my buddies who are closer to that 3k lumen range.

Would have to look back at my dive logs to see what my longest pre-deco Dive has been, but I really can’t recall any time where I was disappointed with the light output.

All these LED drivers will curve down with voltage drops.. so the only real way to have a totally flat curve, is to govern the top end output at the higher voltage levels..

 

[tbone1004]

Not all LED drivers. UWLD uses high voltage packs so they buck the voltage down to what the LED's want. This is what allows them to have a truly flat output throughout the burn. Pretty much everyone else is using 3s packs at 11.1v. UWLD uses 5s packs at 18.5v and the boards buck down. Doesn't matter to most people, but a few companies have light outputs that are truly flat

 

[Caveeagle]

UWLD uses 5s packs at 18.5v and the boards buck down. Doesn't matter to most people, but a few companies have light outputs that are truly flat

My EX35 battery case says:
“Contains three 14.8v, 50wh Li ion batteries”

 

[stuartv]

If anybody cares, the engineer from Dive Rite had sent me these 2 graphs showing voltage and current output over time.

 

[stuartv]

Hmmm... those may not be very readable. If anybody wants them via email, just PM me an address.

 

[tbone1004]

My EX35 battery case says:
“Contains three 14.8v, 50wh Li ion batteries”

so they have a 4s which makes sense, but based on the output curve that @stuartv posted and the amount that they are overdriving that LED, they are likely direct driving it on high

 

[Caveeagle]

Hmmm... those may not be very readable. If anybody wants them via email, just PM me an address.

Umm. That first chart is very blurry,and it looks like the x axis scale is set to exaggerate the visual swing of the voltage drop compared to the other graph.

@tbone1004 , I seriously doubt they would intentionally overdrive the chip past a safe level, but I will ask Jefferson, or Daniel next time I see them. ...just out of curiosity

 

[stuartv]

Umm. That first chart is very blurry,and it looks like the x axis scale is set to exaggerate the visual swing of the voltage drop compared to the other graph.

@tbone1004 , I seriously doubt they would intentionally overdrive the chip past a safe level, but I will ask Jefferson, or Daniel next time I see them. ...just out of curiosity

Those are the charts that Jefferson sent me. I didn't modify them in any way.

The Voltage chart goes out to 1300 minutes. It looks to me like the Current chart also goes out to 1300 minutes (even though the current appears to drop to 0 at about 370 minutes - which makes sense to me, since they are saying it has 6 hours of burn when set to 100% output.

I have emailed with someone (I can't remember for sure if it was Jefferson) at Dive Rite in the past about the HP50 light. That light uses an XHP50 LED emitter, which is spec'ed by Cree for a max of 2600 lumens. Dive Rite claims the HP50 light puts out 3500 lumens.

In my emails with Dive Rite, I was told that, essentially, yes they overdrive the LED quite a bit past the manufacturer's specs, but it is okay because it is being used in water and they have really good engineering that keeps the LED and electronics cool enough that being overdriven so much is not a problem.

So, whether the way they are overdriving the LED in the HP50 or the EX35 is "a safe level" or not is not something I could begin to have an opinion on. But, it seems clear that they are overdriving both by a substantial amount.

That and the fact that they only warranty their light heads for 1 year and their battery packs for 90 days, and they have yet to answer my question about what it would cost to have a light head rebuilt or replaced if it burns out on day 366 or what it would cost to replace a bad battery pack on day 91 makes me additionally reluctant to buy one. Additionally meaning beyond the fact that they do not have constant light output.

UWLD warrants their lights for 3 years and their battery packs for 1 year. That sounds like a manufacturer who has a lot more confidence in their products. 3 years seems like a much more reasonable expectation to have for an LED light that costs as much as these lights do.