Boost drivers lose efficiency the more difference there is between input and output voltages.
If the output voltage remains constant and the input voltage drops, the amount of current it can deliver decreases significantly, so it steps down to a lower mode.
I assume you’re talking about the large steep drops in output.
If you’re talking about the slightly inclined output line which isn’t perfectly horizontal, that’s because of heat.
I know this is the case in theory, but I don’t know to what extent this is the case in practice. The M43 (3S4P) is able to produce max output with cells as low as 3.5V, and the Imalent DN70, although with a 6V emitter, can produce flat turbo output until cell is depleted as well. Imalent DN70 - Review / Vorstellung / Test + Passaround | Taschenlampen Forum
Of course neither these two lights have a boost voltage of 12V, but if the latter turns out to be a hurdle, then I’d preferred something like a 2S2P setup for the Nichia leds, and instead of XHP35 use XP-L in 2S2P. Why complicate it with a 12V XHP35?
I understand there is a qualitative complexity with increasing boost voltage, but I don’t see this should result in a quantitative behaviour that output cannot remain flat.
The bundled battery is not a true high drain one, and ~10A should be the maximum load it can sustain.
EC65 will report a warning (triple flashes for every 5 seconds) when the battery voltage is too low. The lower the battery voltage, the higher the input current is needed for the boost driver to maintain a constant output. And the higher the input current, the more battery voltage sag. That means if the driver keeps the constant output until the low voltage warning, the battery voltage sag will be far too high. And then even though the warning is given on Turbo, there is still much energy remaining unused in the battery.
Yeah, the ones I have are 38 and 41mOhm (DC IR). So they’re a bit worse than a VTC5A (30mOhm), on the same level as a decent sample of a 30Q (mine vary a lot, from 30 to 60mOhm).
I’m intrigued by this light. 21700 support, a nice looking quad, and Acebeam. I only own one other Acebeam (UC15), but was impressed with its quality, output and UI.
However, for $122 I don’t think I want to buy a light that goes poof after just 30 seconds on turbo.
The Meteor M43 does boost to almost 12V! It drives four 3S-LED strings in parallel from a 3.7V battery at 90W. It’s very likely then it can boost to 12V.
The difference between it and the Acebeam is that the Meteor driver is much larger and thus has less heat problems. Also, it wasn’t designed by Acebeam. They go a little bit too close to the absolute limits of the driver components. I actually discussed this with somebody last year who took a look at one of their for drivers (the max current rating of the diodes of his driver was too low).
So mine is coming in the mail tomorrow. Being in 100 degree Texas, I’m wondering if it’s a quick death. I’ve been wanting this one since it popped up on the radar. 82 grams might be just too lightweight for the lights output. I see possible driver improvements and total potting.
They assured me that this problem has been fixed in the new one I received.
To avoid the unexpected quick death again, this time I’m planning to finish all the other tests of my interest first, and after that, I’ll do the accumulated turbo measurement again to see if the driver can sustain it.
One thing is bothering me, though. If we go back to the stock battery, it seems to run for about 16 seconds before ramping down. Is this due to voltage sag?
How many times can you use that 16 second turbo before the battery can’t do it anymore? Once? Twice?
It makes me wonder if they should even classify this as a 4000 lumen light.
I hasn’t tested the new EC65 yet, but for the old one, as you can see in the accumulated turbo curve, it’s less than 20 seconds, only one time. And that’s why I was torturing it with a more high drain LISHEN battery.