Light requiring the most amps?

markr6

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I don't know much about this stuff, so I trying to determine which 18650s to use for certain lights I wondered: which flashlight (production or commonly modded) right now requires the most current? I'm guessing some vn models?

Does a tailcap measurement tell the whole story? I measured some of my lights and they seem to max out around 3.5A. So with some 18650 cells rated up to 20A or 30A, are there any lights actually requiring this much?
 

TEEJ

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Mostly you are talking about highly loaded single celled creatures such as Vinh's stuff...around here at least.

:D

Direct drive lights, and with drives that, if the circuit makes them brighter with more amps...will be brighter if the cells CAN provide more amps.

For an example I use a lot - I have an XT11 that said it could take one 18650 or two CR123.

I measured the output, and, it ran longer on the 18650, but, was brighter with the two CR123's.

I then tried two RCR123/16340, and it was brighter still.

I then tried two IMR 18650 to also up the amps in addition to the voltages, and, it was even brighter than the RCR's, and so forth.


So, it is dependent upon the circuitry...but, if more amp = brighter, the higher amp cells make the light brighter.


Of course, its like flooring your car...more amps at the same or more volts, will use up the mAh in the cells faster too. The mAh on the label is NOT for its capability at 3.5 amps...its typically for one amp or less, etc.

If the light NEEDS a certain minimum amp draw to maintain its maximum brightness, the mAh for THAT amp draw capability starts to become relevant too.


IE: If a light needs 3.5 amps to be at maximum brightness, a cell that maxes at 5 amps might not be able to maintain that 3.5 amps as long as a cell than maxes at 30 amps...

So you also look at how LONG it can provide those 3.5 amps....and that's not listed typically. You look at HJK's reviews of cells for example to get that off his charts, etc.


So, none of the mass produced stuff that REQUIRES higher draw cells don't tell you...but that's a short list. As "requires" is different from "will be brighter with".

If you know the drive type, it will tell you if more amps are better...but as far as "requiring", none of them typically list that unless it is.


I just use light measuring equipment to measure the differences, and, optimize from there.

:D
 
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markr6

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Thanks! So comparing the NCR18650B I usually buy and a high drain like the Samsung 25R, I wonder if I should rethink my strategy and always go with the Samsung since I always recharge around 3.6v. Am I correct saying both cells will last just as long, in the same light, up until ~3.2v?

ncr_25r.png
 

TEEJ

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Yup

:)

Note that the blue and black lines are higher (v) than the reddish lines up to about that point too.
 

markr6

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Yup

:)

Note that the blue and black lines are higher (v) than the reddish lines up to about that point too.

Thanks. I've been around long enough I should know this, but it never really sank in.

I guess I fell for the bigger numbers (3400mAh). There's really only one application where total capacity is a factor for me - when I'm backpacking with no spare cells or way to recharge. Even then, I often don't go below 3.4v or so. Knowing that, I guess my best cell would be something like the Samsung 25R.
 

markr6

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I know I started off topic in my own thread, but I've just been over thinking this for a while!

I made an overlay of these four cells at 5A from HKJ's reviews. I don't really see a reason NOT to get the Samsung 25R. The extra capacity with the two larger cells under 3.2v is probably something I would never take advantage of personally.

18650comp.png
 

WarRaven

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I'm looking at this as, I might gain 50-100 lumens on turbo and most definitely lose from 15-30-60 minutes run time on high.(dep on capacity of high amp cell)

That is dropping from a 3400B to a 3200/3100/2600/2200 etc cap cell for the higher amps, it give higher lumens for a bit and cost in runtime on the levels normally used where high draw is not needed.
Also heat would be amped up a bit more on turbo usage, effecting normal high pattern possibly enough to make it throttle further.

Trade offs IMO, I'll stay high capacity but appreciate where some just want high potential instead.
 

TEEJ

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If the light is run on lower out put, or just doesn't draw the higher amp flows...the higher mAh cells will give longer run time...but, if its a high draw light, the lower mAh but high amp capacity cells will give longer run time at max output than the higher mAh cells.

It seems counter intuitive that a 2500 mAh might last longer on high than a 3400 mAh cell, but if the 2500 mAh is 30 amp capacity, and the 3400 mAh cell is 4 amp capacity...that can definitely be the case.

Again, if you are at moonlight mode and not at a high draw, the 3400 mAh cell still runs longer...and doesn't lose that advantage until the amp load is high enough for it to not keep up.

As there are now 3500 mAh high amp capacity cells, it does simply that dilemma a bit.

:D
 
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