This is purely anecdotal, but I find that with my SFT25R D3AA I use one step lower output than I do with my 519A one.
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Not with a buck/boost, the forward voltage of the LED changes both the thermal throttling behavior and the power at the same current.
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This is kind part of my question. As an example because I don’t have the figures right here, but say the OTF lumens on high of a 519A is 400, and the OTF of the SFT25R is 800 lumens, will we see increased runtimes for the brighter LED to produce the same amount of lumens as the lesser one because it’s running at half the max output?
SFT OTF is 2040 (33% more than the 519a)
519a OTF is 1540
beam focus
SFT beam diameter is maybe 50% smaller than 519a, so it could take 50% less lumens to achieve equal Lux on target
those two factors total 83%…
the mode spacing output difference between Level 5 and Level 6 is 103% (data from 1lumen review)
so it makes sense that w the SFT we could use Level 5 to match the intensity of the 519a on Level 6.
Level 5 uses 0.61A, Level 6 uses 1.31A, an increase in power consumption of 114%
so, in every way, Yes the SFT battery will have longer runtime…
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I love this forum 
Thank you Jonathon.
Had I the spare, I’d grab the SFT for throw and runtime, and at least 3 of the lowest candela to use with diffusers in flicker candle mode.
The FF NOV-Mu in 1800K flavour is sweet in lantern mode.
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Quick question because one of you will know and it’ll save me searching. 
What is the best high capacity battery to run the fairly unfussy Emisar on? I turned up a thread where the Vapcell F12 is mentioned. I put a Wurkkos one in earlier, it flashed 3.9V so I thought that would do for a 20 min dog walk, and I was in the dark before I got home. I’m going to have to keep the battery for the overfussy TS10, but definitely got a surprise as the voltage rapidly stepped down on just under highest ramp on the D3AA. Probably about 3/4 brightness at a guess.
Vapcell best still?
I have the gold 1000 Vapcell and just got in the Vapcell F15 to try when given the opportunity. Without measuring equipment the evidence will be anecdotal but I feel the runtime charts lean toward generosity on the higher outputs of the stepped mode 5-7. However, this for me, isn’t uncommon for a lot of lights.
Thanks. I hadn’t seen the F15, but have a couple of the old gold Vapcell 1000mAh button tops. I’m pretty sure they do better than the Wurkkos branded ones, but like you, it’s a hunch without measuring equipment. I certainly want my D3AA running longer than it did tonight, I have AAA Skilhunts to cover looking in a cupboard or shining in the back of the car, the 14500 format needs more longevity than a fresh NiMH.
Does seem suprising, but, it sounds like the throw you need, calls for too high output, from such a floody optic…
there may be some gains in runtime if you switch to the 10507 optic, for a less floody beam, and thereby manage to run the light a bit lower, so it lasts longer
I also use Vapcel, F12 Flat top, or sometimes the Wurkkos TS10 battery. Im interested in the F15…
Does your dog run free, or on leash?
Hi Jon, I do have the throwy optic in this one. I’d have changed the battery, or taken the Sofirn headlamp if I’d had more time, but wanted to catch some pictures of the moon rising as I’d peeked out the window and realised it was a blood red spectacle and I had to be quick.
Ended up walking further than I thought. I’m gonna grab a couple of the higher capacity Vappers. Claimed mAh on the Wurkkos is 900, even if the 1500 of the F15 is way out, there’s going to be significant gain.
Dog, off lead apart from roads. But she’s not one that needs to be kept an eye on.
Happy Dog!
I asked because you seem to be using near maximum output, so I suspected the need was for the light to reach farther than with a dog on leash…
since you already use the throwy optic, other than bringing a spare battery, you may want a light with more throw… I dont consider a D3AA a suitable tool for off leash dog walking… if it is not producing a long enough beam on Level 5 of 7…
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Very happy dog.
Best torch for anything is the one you have in your pocket when you need it, and it let me down badly. I had zero need for throw, just enough light to shine on the path and I had no prep time at all or I’d have grabbed a Sofirn headlight because I was changing lenses on a phone camera.
This wasn’t a great place for a light to begin a rapid step down. Torch options aside, I’m really just after a better battery, though I might grab another D3AA with the SFT-25R. Whether it’s the one in my pocket when I get a call to dive out the door immediately is another matter.
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Thanks for the photos! Cute doggie
Leaving the house with a spare battery would solve any runtime issues.
The benefit of the D3AA regulated output is that it stays constant… the downside is when the battery approaches empty, the output drops like a rock, with no gradual dimming warning…
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Yup 
Thank, Mimi is a cool little dog, totally obedient, characterful, and my best friend. 
Just looking at Vapcell F15 on Vapcell Dennis AliExpress store. For two, it’s £24, or $31! I’ll have to have a hunt around, or settle for a couple of the 1250mAh golden ones.
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Some places are even more expensive. Convoy has the best price and a discount for multiples. But I couldn’t add them to my cart. So maybe he doesn’t have stock.
Yes. I would like to get a few for testing and use in my various 14500 powered lights. But not at the current price. Hopefully production will catch up to demand so that these become more affordable/practical! I have several H10 and F12 cells to keep the lights running for now. So no huge rush for me to get the F15 cells.
Just grabbed the last 2 from Ecolux. We’re lucky to have these guys, they even tag Mooch. Look how many 14500’s they stock! £5.19, around $7.50.
Didn’t order a throwy optic as I have one in the grey/copper 519A 4500K that can go back to stock Carclo.
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I just ran the 850mAh Wurkkos battery on high and timed it at around 1hr 5 mins until it cut out. Not really a fair comparison but worth noting I couldn’t squeeze 4.2V into it, it didn’t go above 4.1VHaven’t done the Vapcell 1000mAh yet, but the F15 is still giving me usable light at 2hrs 30min. This completely solves my problem.
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2hr 44mins from on and ramped to high on the factory settings at room temp. That’s really very good for a 14500 in any light, I’m impressed.
I can see why mucking about double clicking turbo and running the light high while I fiddled about with the phone the other night led to the Wurkkos battery giving out.
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Very impressive! Thank you for sharing your findings. You said ramped to high, what level was this compared to?