VTC5 aren't made any more right? only one very short run and they were pulled?, so all of them will probably be fakes.
I recently rec’d an email from Efest with this info on a new high current battery:
“18650 2100mAH Pulse current: 38A Capacity: 2100mAh Price 5.1USD/pc. Delivery : 05/Feb”
Price is FOB China, so it doesn’t include shipping.
I asked for a link to a product page, but it is so new they don’t have it up yet. I’ll post it once they get it to me.
this french vaping site quotes Dampfakkus recent tests.They show difinitively that the 2.1Ah 30A Efest is in fact , a Sony VTC4 and the 2.5Ah 35A Efest is the LG HE2.The Efest Sony is correctly specced , but they criticise Efest , in English , for exaggerating the max continious current on the Efest LG.
you know you want the 25R
The ‘sony’ image in the OP is watermarked with ‘mainifire’.
That is the name of the aliexpress store
VTC5 so many fake, not advice you buy it
In most cases, I’ve found the Purple Efest 35A to match or beat the Sony VT C5. The LG HE-2 has different characteristics in the same light when compared to the 35A. I have no true idea whether they’re the same cell or not but in the lights I’ve tested them in they do not appear to function the same. I have some 6 HE-2’s and a couple dozen 35A’s. Also 6 VT C5 and 4 VT C4. I’ve seen cases where one of these would best the others, only to fall behind in another light. So there are things at play that create variances.
I have found the Samsung 25R to be good, but in no case up to par with the 3 mentioned above. It’s a minimal thing though. With the 8 or 10 25R’s that I have though they don’t quite make the power the other top cells make. This is well over 5A, into the top 6A range per cell. Even up into 7A.
I have ~80 flashlights, each loaded and ready to go with appropriate cells. I also have back-ups in a battery box. With over 120 cells actively charged and ready to go at any time, I tend to like the Purple Efest 35A for most lights, most situations.
Of course, that’s just me.
Edit: Want to test your favorite? Build a Quad XP-L in parallel taking one cell. The one I did the other day pulled 15A from the Sony C5.
Edit II: I just pulled wrappers off an LG HE-2 and a Button top Purple Efest 35A. While they are very similar, there are also differences. The HE-2 has identification stamps on it, the Efest has none. The thermal protection valve on top of each cell is different. The metal case appears different in how it was formed or the metal used. Of course, the button top is just a tab spot welded onto the Efest cell, and off center to boot. So, there you have it. Coffee is definitely better than tea.
That’s interesting to hear that the 25r isn’t up to par with other offerings from LG and efest.
I have held off buying HE2’s since I’ve heard a few members being unsatisfied with their performance, but I have never seen any evidence to substantiate this.
Next time I buy a few more high drain cells they will be HE2’s, they are also very reasonably priced compared to efest and even the 25r.
On Sunday , I ordered a pair of 25Rs from Fasttech.Oh well , I’m sure they will be fine for my 3 or 4 amp lights.
Curious that Dampfakkus were so adamant that the E-fest 2.5Ah was an HE2 and yet you have physical differences as well as performance differences.Just yesterday , HKJ posted a test of an Aosibo 2.6Ah IMR that is FAR too close to a VTC5 for a Chinese cell , but not as close as a KeepPower IMR 2.6Ah , which is , of course , a VTC5 rewrap.That’s 2 cells snapping at the heels of the latest , envelope pushing , Japanese and Korean cells.
Something smells fishy but I’m not sure what :~
Is it just me, or is it not obvious that the Efest is an IMR chemistry while the LG is an ICR?
On a side note and of topic, is the HE4 as good as the HE2?
Thanks you for all your insight and testing of these high drains. The ones that I have used are the Sony VTC4. I sold a light and gave him both of them……stupid me!
The ones I am using now are Efest IMR 2500’s 20A/35A and K’Power IMR 2500’s 20A/35A. I just did simple run time tests in the same light and got basically identical numbers. HKJ’s Comparator does show that the voltage sag is slightly MORE w/ Efest.
I am NOT sure if this verifies that[voltage sag differential].I do not have the knowledge that a lot of you guys have! Anyway, I did notice with my 5 minute incremental run time test that when I checked the resting voltages, the voltage ranged from .06v to .10v higher with the Keeppower compared to the Efest.Those were 5 minute increments up to 35 minutes when battery was near depletion!
The HE2 data sheet defines it as a lithium nickel manganese cobalt oxide chemistry , with graphite and SiO overtones 
I think that qualifies as hybrid.The 2 photos of the 2.1Ah efest clearly show that it , at least , is a VTC4 rewrap.
I have not seen a photo of a 2.5Ah purple E-fest doing a striptease.I assumed , given their adamance that E-fest were exaggerating the specs of their rewrapped HE2 , that they had done a similar de-wrap.Maybe they “assumed” a bit as well - not very vorsprung durch technik.Still a lot of loose ends……
This month some VTC4s became available from some reputable sources, but I haven't seen or heard of any VTC5s from a reputable source since last summer.
The HE2 is a great cell that is often overlooked, probably because LG doesn't have the mainstream name recognition of Samsung, Sony, or Panasonic.
I just got 4 cells in from Richard, 2 of each of the LG HE-2 and Efest 35A. So, tonight I put em on a charger together and set out to see how they acted in my Eagle Eye X6 BLF Special Edition Triple XP-L V4 3D.
I ran em each in the lightbox with the 12Ga lead running a loop for the clamp meter, taking simultaneous amperage and lumens readings. I stopped at the 30 second Turbo step down.
Efest 35A started at 12.24A for 3761 lumens
LG HE-2 started at 13.11A for 3723 lumens
Efest 35A stepped down at 11.52A making 3288 lumens
LG HE-2 stepped down at 12.07A making 3371 lumens
Here we see that odd phenomenon where one cell pulls less amperage but makes more output. The LG seemed to be doing better at the step down. Same cell? It would not seem to be the case. Different behavior, different amperages, different outputs.
Beats me, but it is what it is.
FWIW, I’ve noticed that the output is lower running the amperage test at the same time. Putting the light fully together and then sticking it in the lightbox yields higher output numbers.
Edit: Correction, LG cell started at 3723 not 3602 as stated. Dang memory, can’t even see a number and remember it long enough to write it down! (which is why I video’d it 
)
Also interested to see HE2 vs HE4 before i commit to buying. Quick search shows that RMM got some HE4s on monday, currently untested, maybe he will be able to shed some light on this? (Is that pun banned from this forum btw? )
Thread is here
As for VTC5s, searching on a well known auction website in the UK shows three listings, one from a company who specialise in mainly batteries and chargers and seem to provide actual charge values from their own testing (tho only quote manufacturer currents), they show the vtc5 as no longer available. The other two have seller names like phonecases4uonline or similar, they seem to have stock. Naturally, im suspicious…
Think based on this thread i will invest in some HE2s or HE4s to try out, see if they are as good as these ultrafirtles i have lol, the seller i mentioned above describe the HE2 as better than the VTC4 in their opinion so worth a look.
Corin.
Thanks Dale.
I have both those cells,sort of! I have the Efest IMR 2500mAh and also the K’power IMR 2500mAh which HKJ identified in his review as an LG-HE2.
They are both great batteries and are so close in output it would be impossible to visually tell the difference.
I do not have the skills and equipment you have!
FWIW I did run time tests w/ both batteries in the same light. The M25C2vn .Tail standing w/ no fan 64F.
I did 5 minute increments starting AFTER 10 minutes w/ 5 min. rest.
Effest: 10 min-3.81V—
15 min-3.68V—
20 min-3.61V—
25 min-3.56V—
30 min-3.49V
K’Power 10 min-3.89V—
15 min- 3.78V—
20 min-3.68V—
25 min- 3.61V—
30 min-3.56V
I know in HKJ’S battery comparator is shows the Efest w/ slightly more of a voltage sag. Maybe the sevearl hundredths difference in voltage above is a by product of that??
I change the battery ~ the 15 To 20 min. mark because I like FULL POWER!
Remember those output curves at different currents for all the emitters. The ones in the emitter review threads where people put an emitter on copper and tested it at different currents with a bench power supply.
They always rise steeply, then level off, then dip. They all have a “sweet spot” where output peaks. Upping the current beyond this sweet spot actually reduces lumens.
What you could be seeing at 13 amps is the far side of those output curves…. something we’re not used to experiencing in our flashlights. Also, because your emitter probably isn’t mounted on a giant chunk of fan cooled copper, you could be seeing an earlier reduction in output due to increased thermal sag.
I would be suspicious of any VTC5s you see on the market. All of the reputable suppliers I've talked to have not been able to source any since last summer. VTC4s have become available a few times since then, but they were at what I felt were very inflated prices because the 25R/HE2s were available, just as good or better, fresher stock, and cheaper.
I need to sit down and do some back-to-back tests with the HE4. From what I've seen it may be a small upgrade from the HE2, but I don't think it is anything earth shattering.