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

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.

Let IMR know right away so they can check their stock. If counterfeits came in, I’m sure they don’t want any more to be sold, etc…


I totally agree with you

A manufacturer, MANUFACTURING something to have some performance.
This is determined by some limits set by a manufacturer.
If I exceed these limits, then we are not talking about yield that exactly matches the construction.
We are talking about off-limits.

If it is possible or not to operate outside the boundaries of a construction, it is something else.

- My car can reach 200klm / h - 6300rpm.
On the downhill will reach the … 300klm / h - 10000rpm.
But at some point the engine from high pressure …. will break …… -

This means that an engine has some tolerances.

If Mooch or any Mooch states that such a construction has such a performance, it simply tells his opinion.

My opinion is different about why something was being fabricated and what performance this construction took.

Personally, I will read Henrik’s opinion, because Henrik’s temperatures are the same or very close to manufacturers’ statements.

The differences between batteries today are small.
If I get from a battery 3.5 Volts, and from another battery 3.45 - 3.48 Volts, I think I will want to fool myself because I like the …… brand.

I think it’s right to compare the overall performance of a battery, resulting in …
as an overall combinational image
Not just based on how many Amps it was able to perform on a discharge.

Clear only my opinion ……

I purchased 5 LR2170SF at 18650batterystore.com after reading Mooch’s review saying it is the best high capacity 21700 to date outperforming the LG M50 and Samsung 50E and 50E2

Here are my capacity measurements:

Cell 1: 4,782 mah
Cell 2: 4,714 mah
Cell 3: 4,698 mah
Cell 4: 4,524 and 4,566 mah (measured twice)
Cell 5: 4,834 and 4,870 mah (measured twice)

They are only being sold for a super bargain $5.99 right now. I also tested them in the Fireflies E07 and the LR2170SF outputs higher than the Samsung 50E and LG M50. Get them before they sell out or price increase!

With which “charger/discharger/analyzer” did you perform the Lishen LR2170SF cell test capacity measurements? SkyRC MC3000?

Maybe he used a constant current load?

I’m not sure, I have a strange presentiment, let him answer thank you, if I’m right I explain why I asked my question this way and you’ll understand quickly …

Same thing for me :slight_smile:

Xtar Dragon VP4 Plus

Ok thanks for your quick answer, why else did you do this measure of capacity twice on certain cells in particular? And did you change the test slot during the second capacity measurement of these cells? If no, what slot number of XTAR VP4 Dragon did you use? N1, N2, N3 or N4?

I measured those two twice because the numbers seem either too low or too high so I wanted to confirm it. I can’t remember whether I remeasured them on different slots or which slots I used. But I don’t think the slots matter because from my testing, most of my other cells were very consistent.

However, there is a fairly common problem that is revealed with the wear and regular use of XTAR VP4 Dragon (I am at the 3rd replacement of my VP4 Dragon, although I also have a SkyRC MC3000 (which also is subject to this type of problem with wear and time unfortunately, it is not specific to XTAR) and ZKETech EBC-A40L (much more reliable have no problems, but for a device that costs a little more than 180 usd I think it’s normal)), so the recurring concerns are the even-numbered slots, ie the slots 2 and 4 which with the time of use and the wear, end up having a reading wrong measures, which give either too low or too high results, which therefore push us to often re-perform the various tests by bail, but gives again erroneous results too inferior or too high, the only solution being to operate the Charger/Analyzer warranty if it is still running or buying a new one (I know something :cry: …).

I was going through the chart supplied by the OP and noticed a strong correlation between discharge rates and storage capacity. Probably the same thing for recharging lifetimes.

Interesting to me because I have some second hand li-ions that top out somewhere in the 1800mah. I’m in the market for new cells, but can’t make up my mind if I should buy the highest amperage batteries or more higher mah. Then the question, do I care if the lifetime is measured in a few hundred cycles.

Obviously, there I’d too much temptation to max out the light output.

Given history……after much thought and consternation…I will buy the cheapest.

Once again, a thanks to the OP for his great work for testing all these batteries.

I swapped the Cell 4, which was tested at 4,524 in Slot 1 into Slot 4 and it measured 4,520 mah. Slot 4 is where I measured Cell5 at 4,834mah. Therefore this rules out the potential problem you suggested.

You don’t want to generalize too much as far as discharge rates in relation to capacity. You also have to factor in age. Batteries designed many years ago, like 8 or 10, are not comparable to newer batteries. The older cells had less capacity as well as less discharge capability. Like the 2012 Panny B 3400mah with a 5A continous discharge rate and the 2016 Panny GA 3500mah with a 10A continuous discharge rate. Both cells are almost identical in capacity, but the GA is a newer design/chemical mix with much less voltage sag.

As far as charge rates, they can vary a lot. Usually a high drain battery can charge at a higher rate than a high capacity battery, but not always. You really have to look at each batteries datasheet to see what charge rates are recommended/safe.

Keep in mind that 200 cycles (low), if charged once a week, equals 3 years. It’s not like the battery is dead or useless after 3 years though, it just typically has a reduction in capacity of maybe 20%. So I really wouldn’t worry too much about the cycle life. We may have a whole new batch of high capacity, high discharge batteries come out in the next few years that we’re going to want to upgrade to.

I just tested two Vapcell 40T (gold wrapper) and got 4,101mah and 4,156mah, which is an improvement from the older Vapcell 40T (gold wrapper also), which measured 4,038mah. I’m thinking the current batch uses the production 40T, whereas the older batch uses the preproduction 40T.

40T or 50E better for Convoy S21A?

If you mean a stock S21A with “SST-40 6A” driver, the 50E is better suited. With slightly more drain the 40T starts having an edge, and only in high mode. 40T mostly makes sense for a heavily modified flashlights with high current drains.