Test/review of Samsung INR21700-40T 4000mAh (Cyan)

Yes, you are on the right track, but more precisely? (because your answer is a very good clue to find the right answer to my question)

Not sure what do you mean. One cell is 2 years older than the other. Which suggest that one is an older model than the other.
Designation 40S suggests lower discharge rate than 40T. Which may be due to internal improvements. Or may be due to other factors.

My guess is that 40S is just older and technically worse cell.
But maybe you meant something else?

Well, because you’re really close to the right answer, and if I keep telling you that it’s not exactly that, there’s a risk of both going around the answer for a very long time moment, so I give you the right answer.

The 40S is the starting denomination of the 40T, because during its design and as you said before its chemistry and its internal settings were slightly different, which after multiple tests on the part of Samsung SDI engineers was resulted in a significant improvement in its discharge capacity and internal resistance, which pushed them in the end renamed the INR21700-40S to INR21700-40T, so to sum up the 40S is the pre-release of the 40T.

P.S .: Thanks to the Vapcell Technical Manager for enlightening me on this subject.

Thanks for the response. I just checked and the price for the VTC6A is $16.99. I guess I missed the sale price… I guess I’ll wait for the prices to go down a little but I ordered one of the sofirn 21700 lights and need a cell for it. I guess I can use a 20700 or 18650 with a sleeve for now.

Sofirns battery is only $5.50 extra so it’s worth getting.

Another inexpensive 21700 is the Liitokala lii-40A. It’s based on the Lishen which is proven to be a good high drain cell.

Thanks I’ll look at those cells too.

It’s depending on how the cell is used, in which flashlight. I did try several 21700 cells (LG M50, Samsung 50E, 48G, 40T, 30T, Sony VTC6A, LiShen LR2170SA, LR2170SF) on two versions of ACEBEAM EC65 (XHP35 HI and Nichia).

With sufficient cooling, I activated the Turbo again and again, until the cell voltage was too low to sustain that brightness level. And the results are:

For both EC65, the 40T was slightly better than VTC6A. And the AC 1khz IR was also smaller on a 40T.
For a XHP35 HI EC65 (high demanding), 40T provided the longest Turbo.
For a Nichia EC65 (not that high demanding), LR2170SF provided the longest Turbo. This is surprising but yet reasonable, since the characteristics of this cell are between 40T and 50E.

Since some of these cells are not that easy to find, and I cannot assure you that my samples are consistent with what you can buy, you’d better take these results as reference only.

Is there any information if the 40T cell is being sold by other brands as a "rewrap"? I'm looking for a (European) source to get some of them. Concerning the Samsung 40T, NKON needs a couple of weeks until stock gets replenished and akkuteile.de is out of stock and wants a fortune for this battery.

Check out the Vapcell INR 21700 4000mAh 30A with gold wrapper. This is supposed to be a 40T, buy it looks like NKON is out of stock of that as well.

They do have the Ijoy 3750mah. That’s a good cell.

Sony 21700 VTC6A
vs
Samsung 21700 40T

The batteries have the same discharge performance.

If you call “difference” the 0.05 volts, then you are looking for a pin in the straw

With a FET driver will an unprotected cell at 20a - 50a rating just fry a single XHP70? I am trying to understand all the underlying factors here. I want to get a decent stock of 21700 batteries and be able to use them in all my various lights utilizing that size going forward. Do I have to be careful with this? I like using turbo mode some but am worried about frying emitters I might not be able to easily replace. Higher capacity with lower discharge rate seems the safest route overall, but what is the disadvantage of using hi current cells. I rarely run a light until drained. For backpacking runtime is most important at mid light levels. For around the home or shop, topping off a light on a charger isn’t an issue.

Does your VTC6A have a small square QR code at the bottom? Mooch said the ones without the QR code performs slightly worst


It’s like with any battery/emitter combo with a FET driver, each combination of parts has to be matched. You can adjust the output by changing batteries, adjusting emitter wireally diameter and length, etc… You basically can add or subtract resistance to control the output.

Are you refering to a xhp70 or 70.2? Are you using 2 batteries so at 6v?

The disadvantage of high current cells is the lower capacity.

I agree with JasonWW. For me the VTC6 is not better than the 30Q. And when you consider actual OEM cell prices, Murata/Sony can lick my bird. Sony is not shy of providing peak temperature cut-off discharge ratings even sacrificing cycle life. Like VTC4's being rated 30A, but they're not 30A continuous. Of course this makes their figures bigger, though this does not make their products necessarily better.

Source: Bench Test Results: Which lasts longer? VTC6, 30Q, or HG2? @ E-CigaretteForum

^:)

70.2 - Single cell there so probably a boost driver. Sorry. FET drivers on 3 volt LEDs like XPL-HI. Can a high drain unprotected battery be used in both scenarios?

Boost drivers have regulated outputs, so you want the lowest resistance possible. Such as bypassed springs and high drain cells. Depending on the load the boost driver puts on the battery, you can sometimes have too much of a good thing and loose run time.

If you look at this review you can see a light that draws 15 amps. A high drain 30T allows for many full power turbo runs, but capacity is small. A high capacity 5100mah cell only allowed one full power turbo runs, but had much longer running time at lower levels.

Here is more data on the same high powered boost driver light with different 21700 batteries.

What I said earlier still applies to FET drivers. You have to take it on a case by case basis. You would need to be more specific about which lights.

JasonWW - Thank you! Needed to know if I should be sourcing multiple types of 21700. The answer is yes. I will read those threads after work. Appreciate it.

You can mainly read post #1 in each about the batteries.

So far there seems to be 3 main types of 21700. The high drain like the 30T, the high capacity like the 50E and the middle like the 40T.

Someone like DB Custom has tried the 30T with all kinds of emitters with FET drivers. He’s a good person to ask if a specific emitter is going to handle a high drain cell.

Love them (Vaping and flashlights)

Bought two (subpar) Samsung 40T from imrbatteries.com:

Samsung 40T battery #1:
Charge test (Opus BT-C100): 3511 mAh discharged at 0.5A
Internal resistance (Opus BT-C100): 106
Charge at 1.0A (Xtar VC4): 3566 mAh

Samsung 40T battery #2:
Charge test (Opus BT-C100): 3691 mAh discharged at 0.5A
Internal resistance (Opus BT-C100): 88
Charge at 1.0A (Xtar VC4): 3883 mAh

Also bought two (subpar) Samsung 50E in the same order:

Samsung 50E battery #1:
Charge test (Opus BT-C100): 4472 mAh discharged at 0.5A
Internal resistance (Opus BT-C100): 96
Charge at 1.0A (Xtar VC4): 4698 mAh

Samsung 50E battery #2:
Charge test (Opus BT-C100): 4427 mAh discharged at 0.5A
Internal resistance (Opus BT-C100): 93
Charge at 1.0A (Xtar VC4): 4650 mAh

I’ve emailed them the test results but have not heard back. Suffice to say, I won’t be buying from them again.