Where do you find burn time for Big Blue lights (in spotlight mode)?

[dylanfromwinnipeg]

I'm considering buying the Big Blue VTL13500-MAX but the website only lists the burn times for what I assume is video mode. I need to know what the burn time is when in spotlight mode, and I can't find this listed anywhere.

They list lumens for levels 1-3 (which I assume is video mode), followed by another set of lumens also called levels 1-3 (which I assume is spotlight mode). But the burn times only lists one set of burn times, which I'm assuming is for video mode. WHERE ARE THE BURN TIMES FOR SPOTLIGHT MODE?!

I did email Big Blue about it, but I'm struggling to believe the response they gave me is accurate. The email thread went like this:

Me: What is the burn time of the VTL13500P-MAX when on spotlight mode, max brightness? The website lists burn times for level 1-3, but it doesn't say if that is on flood mode or spot mode (I'm assuming flood mode).

BBlue: For VTL13500P Max, the burn time for spot light in max brightness is around 4.5hrs.

Me: Oh that’s surprising (and dissapointing). It lists the burn time for level 1 (flood mode I’m assuming) as 12 hours. And that’s 3375 lumens. Max spot mode is only 2900 lumens. I was expecting burn time to be 12+ hours???

But I got no more responses to my follow-up question.

 

[grantctobin]

Big Blue’s lumens are made up, as is. You can estimate efficiency given the drivers and batteries that they are using, but you’ll probably be disappointed. I’m sure someone will come along that owns said light and will give you reasonable estimate.

 

[stuartv]

It's a new light. Probably nobody here has one yet.

I have its predecessory, the VTL9000P Max. The spot light output is the same (2900 lumens, claimed). The 9000 has 4 x 18650 batteries. The new 13500 has 4 x 21700 batteries.

That is (4 x 3500=) 14 Ah of battery and (4 x 5000=) 20 Ah of battery.

So, the 13500 should go roughly 50% longer than the 9000, comparing the spot lights on High.

But, I cannot tell you how long the burn time is on the 9000 spot, either. I haven't run mine long enough in one day to really tell.

I can tell you that BB told me my 9000 would put out 9000 lumens on High for 3 hours (constant). That was utterly false. I put it in a tub and took pictures. After 1 hour is was noticeably dimmer. After 2 hours, VERY much dimmer. At around 3 hours, it was barely on.

So, I don't trust BB for accurate info on burn times or on lumen output.

My VTL9000P Max is nice, for some types of recreational use. I took it to Truk last month and used it on dives when I didn't take my big camera rig. It was handy a few times to see something I wanted to shoot with my GoPro and be able to switch the light to the flood beam while recording 30 seconds to a minute of video and then back to spot mode.

As far as getting 12 hours of 2900 lumens, I don't even think my UWLD lights that have 160 Wh of battery will do that. 4 x 21700 batteries is CERTAINLY not.

You can look up the power consumption of the LEDs that BB uses and estimate how long a 20 Ah battery pack will last. Remember to factor in that BB lights are not constant output, so the consumption will probably average half of the max consumption rate.

Long story short, I really like 21700 batteries over 18650s. Maybe it's time to sell my VTL9000P and buy a 13500. Maybe...

I got a DGX 1000-6 last week. I'm going to try and shoot some video this weekend in the water to compare that to the beams from the DGX 700 and the spot beam from my BB. It will be interesting to see if the BB is any brighter at all than the DGX 1000-6.

 

[halocline]

I wouldn’t assume the same lumens/burn time relationship in flood and spot mode. I don’t know enough about how these things are measured to make that connection.

But, I do have some years experience with big blue primary lights, not video, I think the ones I have are the TL4500 and one size smaller. The bigger one has 4x18650 and the smaller one has a single larger battery. I’ve run burn time tests on them and basically, what I’ve found is that on the highest settings, they slightly exceed the spec, but on the 2nd setting, which is supposed to be half the lumens and double the burn time, they’re well under. The other side of the coin is that the light is not much dimmer on the second setting. I’ve talked with big blue about it; they’ve been very friendly and sent me new batteries and replaced a charger, but I came to realize that those published specs for the burn times/lumens are not accurate. I still use the lights, I like them quite a bit, and they’re not expensive. I just do my own burn tests and plan accordingly.

 

[stuartv]

I did burn tests with my BigBlue VTL9000P Max shortly after I got it.

BigBlue support emailed me that:

If you turn on the flood beam on the highest beam (9000 lumens) it will stay on 9000 lumens for 3 hours. Near the end of the battery’s life, the lumens will diminish slightly.

That was completely false. I put it in a bucket of water and took pictures with my fancy camera in full Manual mode, so exposure settings were always the same.

It clearly got dimmer as it went AND, at the 2.5 hour mark, the LED ring around the power button was flashing red and the output was very dim. That was in the Spot beam mode, on High.

Same test in flood mode on High, after 1 hour, it was quite noticeably dimmer. I didn't run it any further in that test as the point was to verify the claim above that it would do 9000 lumens continuously for 3 hours. It clearly wouldn't even do it for 1 hour...

 

[stuartv]

Regardless, for many purposes, that type of light and performance is more than adequate.

For that reason and the ~50% more battery capacity, I ordered a VTL13500P Max today to replace my VTL9000P Max. 50% more burn time in the 2900 lumen spot mode should be useful at times.

I will post some kind of report after I receive it and have a chance to use it.

 

[stuartv]

Me: What is the burn time of the VTL13500P-MAX when on spotlight mode, max brightness? The website lists burn times for level 1-3, but it doesn't say if that is on flood mode or spot mode (I'm assuming flood mode).

BBlue: For VTL13500P Max, the burn time for spot light in max brightness is around 4.5hrs.

Me: Oh that’s surprising (and dissapointing). It lists the burn time for level 1 (flood mode I’m assuming) as 12 hours. And that’s 3375 lumens. Max spot mode is only 2900 lumens. I was expecting burn time to be 12+ hours???

Also, you probably shouldn't be too surprised by that. And it may be more or less accurate - if you understand that burning on Spot High for 4.5 hours means that there is still some glow coming from the LEDs at the 4.5 hour mark, but it may not actually be a useful/useable amount of light.

The 9000 on Spot High will go for roughly 3 hours (to still just barely on). The 13500 has roughly 50% more battery capacity, so 50% more burn time is a very reasonable expectation.

The reason the Wide beam can do 3375 for much longer is the difference in power efficiency of the LEDs involved.

The Wide beam at 3375 is running a whole bunch of LEDs at a very low current. They are very power efficient like that.

The Spot beam at 2900 is running only 3 LEDs to put out a comparable amount of light. Each LED has a LOT more current going through it than in the Wide mode scenario. Those LEDs with higher current use disproportionately more power. 3 times the current, to get 3 times the light (per LED) is way more than 3 times the power.

Why don't they use more LEDs with less current to get longer burn times for the Spot mode, too? Optics. They can't get 11 LEDs to focus down to a tight, spot beam the way they can with 3 LEDs.

Anyway... if you haven't bought anything yet, and you're interested in a deal on a VTL9000P Max, I'll have one in very good shape for sale, soon. We are a Big Blue dealer at the shop where I teach, so I believe I can sell it as a demo unit, still with a receipt and BB warranty. If you're interested in that, send me a private message. Or just keep an eye on the Classifieds here. Once I get the 13500, I'll post a for sale ad there for the 9000.

 

[dylanfromwinnipeg]

It clearly got dimmer as it went AND, at the 2.5 hour mark, the LED ring around the power button was flashing red and the output was very dim. That was in the Spot beam mode, on High.

Same test in flood mode on High, after 1 hour, it was quite noticeably dimmer. I didn't run it any further in that test as the point was to verify the claim above that it would do 9000 lumens continuously for 3 hours. It clearly wouldn't even do it for 1 hour...

So the VTL9000 on spot mode only gets 2.5 hours before flashing red?! That shocking! My VTL3800 gets 4 hours before flashing red. I would have expected the 9000 to be significantly longer burn time than my 3800.

 

[stuartv]

So the VTL9000 on spot mode only gets 2.5 hours before flashing red?! That shocking! My VTL3800 gets 4 hours before flashing red. I would have expected the 9000 to be significantly longer burn time than my 3800.

The 9000 is 2900 lumens in Spot High.
The 3800 is only 1200 lumens in Spot High.

The 9000 has 14Ah of battery.
The 3800 has 6.5Ah of battery.

I would totally expect the 3800 to last longer putting out so much less light.

If you switch the 9000 to Spot Medium, I think it is then 1450 lumens. It's still more light than the 3800 on Spot High and I suspect it will also significantly outlast the 3800 on burntime like that, too.

 

[dylanfromwinnipeg]

@stuartv definitely update us on the burn time of your new light. I don't dive during the summers so I have some time before I have to decide on which light I want.

The bigblue website also lists 2 different battery sizes for the new light, just above the price they say it's 21700x4, but lower down in the specs table they say 18650x4. I hope your right that it's 21700's.