sk68 lasts how many minutes with "real" 800mah 14500 battery?

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bionictony
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sk68 lasts how many minutes with "real" 800mah 14500 battery?

about how long will a sk68 last with good quality 800mah 14500 battery? sorry, i don’t know how to read those battery review charts.

i ordered this before i knew better. i got those 2500mah 14500 batteries. my own basic testing is that it lasts about 16 minutes on high before fading. this is just 1 battery out of the 4 pack that i ordered.

Angler
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I think there are many clones and versions of the SK68, each of them with different leds and drivers. This means the power consumed by an “SK68” varies based on these differences. This being said, it is impossible to tell you how long it will run on 800mah without knowing the power consumption of your specific unit. Also, power consumed may even vary depending on which battery you use, higher quality batteries delivering higher current and therefore depleting more quickly.

It does sound like the cells you have are less than 800mah. Your light will VERY likely be brighter AND produce usable light for longer with a legit 800mah cell. Curious what brand are the cells your purchased?-

bionictony
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they are GTF 2500mah 14500 from aliexpress. i guess since you cant tell me how long, is 15 minutes of full light acceptable from any given flashlight with 3.7 cell battery?

keltex78
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Measure the tail-cap current of your light with a freshly charged cell to see what kind of current level your drive is pushing. You can use that info to estimate (very roughly) what kind of runtime you could expect.

http://www.digikey.com/en/resources/conversion-calculators/conversion-ca...


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Don wrote:
It sounds like the XM LEDs won’t really be suitable for flashlight use. Pity…

antiparanoico
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bionictony wrote:
… 2500mah 14500 …

That’s a typo, the manufacturer meant 250mAh.

If anything can go wrong, it will.
Matter will be damaged in direct proportion to its value.

Angler
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bionictony wrote:
i guess since you cant tell me how long, is 15 minutes of full light acceptable from any given flashlight with 3.7 cell battery?

It’s not quite that simple. For some high-amp lights on small mah cells, yes, 15 minutes is acceptable. To estimate runtime, one needs to know how many amps the lights draws, and how many mah the cell contains. Then some sort of prediction can be made. To give an estimation with two unknown variables is not possible.

It sounds like you want to know if 15 minutes is acceptable for “your” light. With no supporting information I would say no. And I think the entire forum would suggest you buy a better cell for this light. Not only will it run longer, but it will likely be brighter also. These cells you have are extremely questionable and probably dangerous (think explosion).

sedstar
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heck, i have a light that runs 120ma on LOW mode, and a big 26650 in it… i turn it on at DARK, and turn it off at morning… by morning? it was still 3.7v, having started out at 4.2 ish…

by contrast? theres some light rockets the guys here have made that probably would not last more than a couple minutes, lol

also, lithium batteries capacity (assuming the manufacturer doesnt LIE in the first place, lol) isnt a straight line on a graph. By that, i mean this…

lets say you have a .5amp light…. thats the draw on the battery. You have a 2000ma battery capacity. Simplified wisdom says 500ma (half amp) draw out of a 2000ma capacity battery will yield 4 hours…

also, a 100ma small light? on the same battery? should by this reasoning give 20 hours…

its not linear like that. The battery acts like a higher capacity battery at lower draws, and as if it had less capacity at higher draw.

also theres the matter of capacity vs high rate…a battery rated for 30amp short high draws, will likely have less capacity than if it had been designed and rated for only 5 or 10amp short high draws…

reccomendation and reputation are everything… which the lads here hand out freely, of course.

With enough black coffee and cigarettes? all things are possible…

I am currently still shipping… REAL GENUINE CREE xp-g emitters, the classic… brace yourself? as low as 20 cents apiece!! Check out the SALES THREAD, everyone is happy… then PM me

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CRX
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You should probably be getting 30-40 minutes in high mode from a good cell such as the sanyo 14500P in the average sk68.

hank
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I’ve never been able to let any SK68 just sit turned on — like when I tried to use one to light up work in a crawlspace.
They just get too hot fairly fast, in my experience.

dchomak
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antiparanoico wrote:
bionictony wrote:
… 2500mah 14500 …

That’s a typo, the manufacturer meant 250mAh.

And that’s being optimistic!
The first cells I got were less than 200mAh.

djozz
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I did a runtime test on a sk68 clone with XP-E led a few years ago, as a control for a mod, it lasted about 25 minutes on a Efest IMR 750mAh battery. Here’s the graph from that post:

Barkuti
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antiparanoico wrote:
bionictony wrote:
… 2500mah 14500 …

That’s a typo, the manufacturer meant 250mAh.

ROFL! Big Smile

Not so recently, a friend of mine showed me a set of BTY 2500/3000 mAh μAh Ni-MH AA’s. When I asked him why did he believed these were good after prompting him to compare their wheight against an old known brand-name set, he told me he thought the new ones were made “from light alloy”.

Cheers

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djozz wrote:
I did a runtime test on a sk68 clone with XP-E led a few years ago, as a control for a mod, it lasted about 25 minutes on a Efest IMR 750mAh battery. …

It’d be interesting to know what kind of tailcap/driving current was pushing that driver.

UltraFire SK68 LED Flashlight w/ Focus Zoom discussion at FT. That one seems nice, a user reports 1100mAh of tailcap current.
Not a single mention about the thermal path on these units. :-/

Cheers

bionictony
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this thread has been a good read. i’ll toss the cells as soon as i get some sanyo 14500 batteries in. i store all my unused radio control lipos in a ammo box just in case.

do these 14500 batteries just swell up or just catch fire if discharged too low?

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sedstar wrote:
heck, i have a light that runs 120ma on LOW mode, and a big 26650 in it… i turn it on at DARK, and turn it off at morning… by morning? it was still 3.7v, having started out at 4.2 ish… …

Underwhelming, to say the least. 3’7V no load voltage is probably at about 35% SoC so, even assuming that you run the light for 12 hours at 120mAh tailcap promedium current, that 26650 of yours seems to be a dog… Facepalm

Cheers Party

djozz
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Barkuti wrote:
djozz wrote:
I did a runtime test on a sk68 clone with XP-E led a few years ago, as a control for a mod, it lasted about 25 minutes on a Efest IMR 750mAh battery. …

It’d be interesting to know what kind of tailcap/driving current was pushing that driver.

UltraFire SK68 LED Flashlight w/ Focus Zoom discussion at FT. That one seems nice, a user reports 1100mAh of tailcap current.
Not a single mention about the thermal path on these units. :-/

Cheers


1100mA sounds about correct, I have seen 1.5A for a sk68 clone as well. And with its thin aluminium board, no thermal paste and hollow pill it performs remarkably well, see the graph above.

There’s a gap between what we think how good the thermal should be here at BLF, and what limited heat-path a flashlight without any problem gets away with.

Barkuti
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bionictony wrote:
… do these 14500 batteries just swell up or just catch fire if discharged too low?

Don’t think so but, deliberately keeping them over-discharged for sufficiently long courses of time may inflict permanent damage to the cells.

Lithium-ion Safety Concerns @BU
Interesting article.

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Barkuti
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By the way, what kind of baseplate are these usually equipped with? 16mm round?

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CRX
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16mm MCPCB i think, but it’s been a while since i opened one up.

Hammerman
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a 14500 is 14MM in diameter and 50 mm long and circlular O

a 14 50 O

A boost driver in the sk68 means you shouldn’t be running 14500’s in it on high till it’s depleted anyway . certainly not without a meter or without protected cells

snakebite
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add an o to the name and subtract a 0 from the capacity.
one i tested came to 317mah.and comments here lead me to believe that one is better than most.
i have seen sk68 style lights built with nice buck-boost drivers all the way to direct drive li ion only cheapies.
measure current at the tailcap as mentioned earlier.

bionictony wrote:
they are GTF 2500mah 14500 from aliexpress. i guess since you cant tell me how long, is 15 minutes of full light acceptable from any given flashlight with 3.7 cell battery?
Barkuti
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snakebite wrote:
add an o to the name…

I was just thinking about that yesterday while LMAOing!

snakebite wrote:
… and subtract a 0 from the capacity. …

I’d say “detach a 0”… ROFL!

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Angler
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bionictony wrote:
do these 14500 batteries just swell up or just catch fire if discharged too low?

The cell could go into thermal runaway, venting violently, possibly catching fire.
Also, the greatest risk is when you go to recharge it after discharging.

With these shady cells, we have seen things such as the canister actually containing a small lipo inside instead of the li-ion roll that should be in there.

sedstar
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QUOTE “sounds like your 26650 is a dog…”
ENDQUOTE

hey, thats fair. Whatever… but.. .WAIT a minute… that wasnt my good 26650… my mistake…

PS – actually, i “misremembered”… ACTUALLY the “3.7 volts no load the next morning?” was actually one of my 4x “sh!tfire” 18650s i have? I dont actually expect those things to have any capacity… heck, if they give up 8 or 10 hours on “lo mode, 120ma” thats all i expect out of sh!tfire 18650 batteries, lol…

=======================================================================

i just bought a “DeWorld” dual channel charger on clearance at RatShack a ways back… this was before i ever ordered from china before, and didnt ever yet use MTN before… so…

shrugs

dual channel charger made me happy, came with 2xAA-sized Lithium, so at least i had SOMEthing to run both my 68s i had acquired… one AA lith didnt work, but… on clearance i couldnt complain as the other was good…

clearance being clearance, i picked up 2×26650 “DeWorld” at the same time… price was right, and, others had bought them and said they were decent.

the sh!tfire batteries? i dont even remember where all 4 of them even CAME from… i think my first 2 came from a “yard sale”, they charged up, so, i toss them in the pile… the other 2? i got a cheap charger basically for free when i bought a cheap zoomie light, so, now i have 4 sh!tfire 18650 batteries…

i just use them for “wimpy lights”.
==================================================================================

but, thanks for bringing it up, actually… coupe of guys did capacity tests on the 26650 radio shack “DeWorld” batteries, and said they were cool… i use them in any of my three 1504s from the group buy we had… they seem to run good in them.

since you made me think about it? i’ll have to run my 26650 cheapie zoomie on “lo mode” charged up, and then see what the no load voltage is like 8 or 10 hours later, lol… i bet its pretty good…

my basic plan, was that since people on HERE has said the “radio shack 26650s” on clearance tested good? the idea was my cheap china zoomie i sorta like? has a pretty low “lo mode”… i figured i could go all WEEKEND fishing or camping on one of my 26650’s, let alone having a second one charged up for the trip…

============================================================================

heck, THESE days? i now know if i ever want a “real battery” here in the USA? i just order a “kong” or whatever from MTN and i am good to go…

With enough black coffee and cigarettes? all things are possible…

I am currently still shipping… REAL GENUINE CREE xp-g emitters, the classic… brace yourself? as low as 20 cents apiece!! Check out the SALES THREAD, everyone is happy… then PM me

SALES THREAD:
http://budgetlightforum.com/node/52528

if you are into reloading? this is my site… I inherited the remains of what was once arguably the best reloading site on the internet… its the “BLF” of reloading sites…

http://reloadbench.freeforums.net/

if you think night vision would be cool? It IS… this site i am a member of, and its basically the “BLF” of home made scratch-built digital night vision. They are at the leading forefront of advanced DIY for digital night vision, and thats gun mounted or handheld… builds rival and exceed commercial offerings…

http://nightvisionforumuk.com/

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Hello! Smile

Mmm, just saw this unusual CREE Q5 1200Lm Zoomable LED Flashlight Adjust Focus Torch Lamp Light 3Mode 14500 bla bla bla SK68 clone.

In the specs it is said it only works with 14500 li-ions. Heck, I may give it a try, though honestly, I don't really need it. It is only because I have a couple of unused TF Flame IMR14500s.

What is the size of the driver board on these? 17mm?

 

Cheers Party

Barkuti
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Mini LED Flashlight 3W 2000LM Aluminum Zoomable For Cree Torch Waterproof mount Flashlight Linterna Lampe Torche

Well, mainly looking for a decent cheap 3-mode driver host since I’m planning on swapping its stock emitter.

Cheers Party

Barkuti
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Cheers 

P.S.: overpriced bullsheesh.

jerm03
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Just try it if you have the battery. I suspect about 1 hr on high.
Jerry

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Found that on an SK68's pill a friend just gifted me. Tailcap current looks to be close to 1'25A on a li-ion cell. Looks good to me. I may add an R330 over the R120, should boost the driving current to 1'7+A… 

 

Cheers Party