14500 battery from Fasttech-which one for SK68 clone

I have two sk68’s, one from T-Mart, one from a reputable Ebay seller. Both lights shut down very quickly (about 10 minutes ) using fully charged 14500 Protected Flames. Both cells charge up to 4.18v. I haven’t taken the lights apart to check for thermal paste, but I’m guessing there isn’t any. I wonder if this is a case were thermal paste under the star would increase the runtime?

Dunno. Some of the 68 clones specificaly state to not use 14500’s.

Thermal paste is cheap enought to try, but I really don’t know for sure about your shutdowns. Just a guess…Could be overloading the drivers.

Well then, the 14500 LiFePO4’s may be worth consideration.

Yeah flames are great in mine, anyone tried IMR? Any extra output?

My SK68 came from the ebay site which had been linked for this thread below, (the original post was edited and the link was removed when the price changed).

It seemed unanimous that the 14500 worked fine in it.

Trustfire Flames versus Nitecore, I was hoping to get a few more comments to push the balance to one or the other.

What about the 900mah versus 750 of the Nitecore?

LiFePos are brighter and simpler to use, cheaper as well… and are readily available locally…Home Depot has them.

Fasttech has 4 of those ranging from $2.14 to $4.71, any preference?

Since they are 3.2 volts and the Li lon are 3.6/3/7, why are the LifePos brighter, and are they safe to use in this light?

I have Trustfire, KeepPower, and Nightcore 14500's. Without a doubt, the Nitecore's I got from Fasttech are the best. They are the only one's I have the meet or exceed their mAh rating. The keepPower are inconsistent diameter wise. 2 out of the 4 I bought from KumberBear will not fit my Xeno E03 because they're too fat. The Trustfire's suck. They don't come anywhere near their rating BTW. I have 8 Trustfire's I got from Manifont and they all blow

They are safer to use than Li-Co

For a single 18650 application, they will not be brighter unless your light can handle up to 7.2v at the upper end. If it does then you could use a couple of 123A LiFe cells which might make it brighter. LiFePO4 make my Spark SD52 run much brighter.

I got the Sanyo 14500 cells with the tabs. OK capacity, not great, and a lot of drop out (indicates high internal resistance) with a 1A load. I would not recommend them based on the ones I got. I also found this discharge graph from the FT discussion on that item. Closely matches what I got as well. ;(
I have TF Flames from DX that have better capacity and less dropout. I’m thinking of getting one or two of the Nitecore ones, pricey but sounds like a winner.

The light in question is a SK68 clone from ebay, and the original question was about which 14500 to use in it.

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Nitecore seems to be getting some convincing praise.

All these batteries should be good for what, 5-7 years of light usage?

I’d say five years anyway, with maybe 20-30% capacity loss at the end. It does depend a little on usage, but a lot more on storage.
Store at a cool temperature (i.e. below 30C) with a resting voltage of 3.80V. Fully charged or at higher temps, they will degrade much faster.

PyTech - Sean :slight_smile:

Sounds like those batteries are dying very quickly, my TF flame 14500 batteries get at least 20-30 min on hi. You should start out with 2 fully charged batteries and as soon as the first one cuts out put the other charged battery in it to see if it’s a heat issue or battery issue, cuz the light is supposed to shut off when it drops to a certain voltage. Maybe you just got bad cells

OK, just completed a discharge test, 582mAh. Here’s the graph:

Not terrible, I guess. Drops to 3.7V rather quick. I do not have a curve from another cell to compare, but I guess in an SK68 they would be bright for a little while. I still think there are better cells for a little more money.
Edit: Forgot to mention, for those who didn’t click on the product link; these are unprotected cells.

I didn’t write that comment very clearly, but I intended to say that the LiFePo is brighter than a AA.

I feel better using LiFePos in AA lights over Li-Ions because of the lesser voltage. I can substitute one LiFePo for 2-AA in an equitable swap, and the single AA lights I use them in don’t have an issue with the additional voltage. I do appreciate the brighter beam on the singles, those lights are marginal on AAs, and I am not trying to hotrod my AA lights, I just need them to work reliably when I need light to see.

I would not want to play around with any of my good lights either, like the Fenix lights, but my SK68 is not a primary light for me, and everyone says it is safe to use the 14500, it’s only value to me really is for goofing off with, and showing it to people and to keep by the thermostat or something, so the brightness is the real reason that I bought it.

Here’s a graph that compares the Sanyo UR14500L2 to the TrustFire Flame 14500 Protected (from DX). I had two TF cells, and I removed the protection PCB from one. The graph speaks for itself.

Sanyo capacities tested around 560 and 600 mAh.
TrustFire capacities were around 750mAh for both cells. The protection circuitry has a minor affect (about 50mV at the most) on the voltage during discharge.
For $1 more, the Trustfire cells easily outperform the Sanyos. I will reiterate that my TF cells were from DX. There is a chance that the Fasttech ones could produce different results.

Happy to see your graphs, Relic. I was going to recommend the trustfires as well as I've never had a lick of trouble from any except for the counterfeit pair I got from BIC a year ago. The ones from fasttech are great and genuine. I hate it when people bad mouth all xxxxfire cells. The genuine Trustfires are great in every size they make. It's the Ultrafire celks that are crap. This process they are better than the Sanyo 14500s.