Hello!
Im trying to make a very small light. What is the absolute smallest that has LVP? I was looking at hank’s kc1, but it doesnt have lvp.
I do not need fancy, not even any emitter requirements because I’ll look for what led to use afterwords. If its a multi mode that would be great, but even one mode is fine (twisty)
Thanks!
The smallest “smart” driver I know of that’s available for sale: the MTNElectronics 10mm FET driver
The LVP depends on the specific firmware being used, so make sure to read the description.
If using a small single cell like a 10440 or maybe a 14500, it should be fine to use with a single Nichia 519a
Im planning on using a 10180 lmfao
But now that i think about it, could that be an issue? Or can i just choose any driver? Im thinking if i settle on this driver, should i get it with a max level of like 50%, 25%, something like that?
I’d go with the max level of 100% just because of how limited the 10180 can be
fair enough. my reasoning was that its already an older cell (someone gave it to me after their light died), and getting batteries is already a pita in canada, so i may as well help it out a bit.
But actually i could just get the guppy firmware. Do you know the difference between Revision 1 and 2 of that fw?
Almost all LED flashlights have a sort of defacto low voltage protection inherently built in because most white LEDs won’t turn on in the low 2V’s. So it’s kind of a built in low voltage cutoff.
Its lower than most people would prefer to go and it’s nice to have a real cutoff that’s higher than that of course. But it’s really just the incandescent flashlights that you have to worry about draining a battery to below 2V. Or parasitic drain.
Btw I have some spare 10180’s i can send you if you want. I’m in Canada.
A LiIon cell that was discharged <2.4-2.5V is imo not safe to use anymore.
True, i could just go off of brightness. However like you said, a firm cutoff is ideal, esp because its not good to discharge under 2.5v
Also thanks for the offer! I’ll pm you
You shouldn’t be discharging a li-ion cell below 2.5v, that is most manufacturer’s “do not recharge” voltage.
Proper LVP is especially important for a cell with a capacity as low as a 10180 (only a measly 80mAh)
I don’t use mtnelectronics drivers myself, as the international shipping cost to my country is too much. So I don’t really know guppy firmware, I just end up using biscotti for my mechanical-switch lights
Fair enough. Its also a bit steep for me (17$ usd!), however at least its not on a 2$ peice of glass that they were gonna charge me before
No its not. You know that. Comeon. What are we doing here lol
There is a reason the low-voltage protection of most lights is at around 2.7v, most manufacturers specify an end-discharge voltage of 2.7-3.0v, some go down to 2.5v (most notably Molicel) but not below that. Certainly not the low-2v (2.0-2.3v) you suggest where a white LED no longer lights up at.
Can you possibly drain a cell to <2.5v and get away with it? Maybe
But I’ve had cells substantially increase in the rate of self-discharge after doing that (turns out some lights have high parasitic drain), but it’s just not worth it for the tiny last bit of extra energy left below 2.8v for most cells.
I try to stop discharging at 3.0 or 2.7v depending on the load, and that is easy to overshoot with a 10180 light (it’s like 5 minutes of high in a GT Nano)
Edited: Seems like 2.5v end-discharge is fine with modern cells. Though I wouldn’t really trust a random-brand 10180
Read datasheets. All modern lithium can be discharged down to 2.5V.
After doing some reading, I stand corrected, my information was outdated.
I would still recommend LVP for such a small cell though, it is very easy to overshoot 2.5v