Yes, indeed, most people do have power banks.
But some of us also have a lot of Li-ion cells and we like to go the extra mile.
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I am waiting for a IR tester to arrive in a few days and I will do some resistance comparisons.
I will also test the power bank function to know for sure if it works: what voltage and current.
I hope everything will go well… 
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I did a short test with my Vapcell S4 Plus V3.0 in the power-bank mode, with 4 brand new Molicel P28B 18650 batteries (only one storage charge at 50% - 3.7V since i got them) !
So i decided to check them out how they are after a few months in storage !
When i put them in the charger they were pretty good ( some of them was at 47% and some others all most 50%) after the “charger reading” in a few minutes the charger started beeping that i had completed battery at 50%, so im good so far… !
Then i plug them on the phone when it was 30%, and after the short test (almost 1 hour) the batteries are down to 30% and the phone up to 70%, so i stop it because i didn’t want to “force” the batteries below then that !
So im pretty good with that, no problem, no smell, no heat, no nothing, everything is working perfectly ! Im pretty pleased with it !
Dennis, could you please confirm whether S4+ supports also 20v, which would be required for the “conversion head” to work for providing 60w? I don’t want to find out by trying.
Vapcell s4+ V3 and YR1035+ resistance tests:
Cell used: Wurkkos 21700 5000mAh
For Vapcell charger I measured several times (3-4) in each slot and set the lowest value.
For YR1035+ I only made 4 measurements.
Vapcell s4+ V3 (DC) Internal resistance measurements:
Slot #1 23 mΩ (lowest)
Slot #2 21 mΩ (lowest)
Slot #3 21 mΩ (lowest)
Slot #4 22 mΩ (lowest)
YR1035+ (AC) Internal resistance measurements:
Test #1 12.98 mΩ
Test #2 12.98 mΩ
Test #3 12.90 mΩ
Test #4 12.95 mΩ
What I observed:
- The measurements are more consistent if:
- Contacts are cleaned with Isopropyl alcohol 99%.
- Cell is twisted few times inside the charger.
- Bigger cells have better repeatability on tests (probably better spring tension and larger area of contact).
The repeatability issue lies in the charger zinc-nickel plated contacts.
At milliohm level, these kinds of contacts show their weaknesses.
Maybe some gold-plated contacts… 
The power bank function of Vapcell S4+ V3:
I only charged my phone. No heat, no error, just charging.
From what I’ve read on the forums, it seems that the unfortunate cases happen mostly while charging power banks.
It seems like a bad USB handshake between certain models of power banks and the charger.
Voltage: 5.07V
Current: 1.38A
I hope they release a v4 with better algorithm for IR and better power bank function.
Until then, I’m happy with the charger for my needs.
Happy New Year!
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Vapcell measures DC IR, Yaorea measures AC IR.
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Yes, the YR1035+ uses 1kHz AC.
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Do you know how Vapcell executes the DC IR measurement? There are a lot of ways to test it and a lot of factors could be of influence.
Below is a bit of an older topic, but as far as I can tell still relevant, but there is a lot of information (and interesting discussion) on how certain things could be of influence. (And therefore getting consistent and repeatable results.)
From this post onward is the most useful/interesting information:
No, I don’t. Thanks for the link, interesting info.
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After reading all the above, I am still confused. Well, here’s the summary below.
看了半天也没个答案，我来总结一下大家的疑惑：
1、S4+V3官图配的那个TYPE-C转接头看起来就是个PD诱骗器，用来诱骗PD充电器输出特定档位电压，问题就是只能诱骗不能转换，PD头支持哪些输出档位的电压电流就只能用其中一个；
2、S4+要求的输入电源规格是DC12V/5A，问题就在于什么样的PD充电头满足这个要求，PD3.0规范只有12V/3A、20V/3A，PD3.1走PPS模式可能会达到12V/5A；
3、希望技术确认的问题：（1）PD充电头规格要求，是不是满足PD3.1规范的65W及以上就可以，走PPS输出12V5A？（2）PD2DC转换头就是那个诱骗器的要求好像还需要一根带E-Marker芯片才能跑到5A及以上？
4、如果这个路径没有问题，建议是提供一个PD电源线可选项，整一根PD2DC转接线，就别单独整个诱骗器IC，感觉很不靠谱。
I’ve posed this question myself a couple of times now, but have seen no response, so my current working assumption is that this design defect likely has not been corrected. I would not assume otherwise. A ~-50% error is not ‘inaccurate’, it’s invalid (and IMO completely unacceptable); and yes, you can do much better in a 4-slot ‘analyzing charger’. This is not just about ‘consistency / repeatability’, which is a different subject; it’s about gross inaccuracy by design.
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From what I’ve heard, DC IR is different from AC IR. ("ACIR has a different value than DCIR)
By what method are the cells specifications obtained?
DC or AC?
We need to know this to measure them correctly.
If the specifications give a DC value and we measure AC, we will have a problem…
Does the algorithm of DCIR take account of conversion/difference between the AC and DC? What is the standard measurement for LI-Ion cells?
Someone with more expertise in the field can shed more light on this.
Here is a decent discussion on the topic of AC versus DC IR:
So is this one:
From what I know, the manufacturers us AC IR for their testing. But I find that using DC IR, while not being directly comparable, has value in judging cell health over time, regardless of the raw values. As long as the device you are using has good repeatability of measurements. Something that many of the popular chargers are not real good at. The stand alone AC IR meters ae better at this.
Not really a problem, as long as one understands that, while the readings are correlated, they are not the same. But both can be used to help assess cell State Of Health.
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From what I’ve heard, DC IR is different from AC IR. ("ACIR has a different value than DCIR)
Yes, it is far different, and as a practical matter, the two (simple DC resistance and complex impedance (so-called ‘ACIR’) have almost nothing in common in terms of the electrical properties being measured or the way those measurements are used. They are however both expressed in ‘Ohms’, and that, understandably, confuses many.
They are both valid electrical properties and are both useful measurements. From the cell manufacturer’s perspective, both are important depending on the application environment. If the application environment involves primarily pure DC signals (such as a flashlight), only simple resistance (DC measurement) is directly relevant. In other applications where significant AC signals (or DC signals which have a significant AC component, such as pulsating / varying DC) exist [think motors, motor drives, EVs, etc.] , the complex impedance becomes very important (and that is measured using an AC test signal from an impedance meter.)
In the flashlight environment, all the calculations I do require use of the cell’s ‘simple resistance’, or ‘DCIR’. Calculations of the voltage drop which occurs across a flashlight cell, and thus its impact in terms of voltage delivered to the load (the so-called ‘light engine’), or current flow in the circuit (which is relevant to voltage drops across other sources of resistance in the circuit such as connections, battery springs, etc.), must be made using the simple DC resistance (DCIR) of the cell. This also applies to calculations of power loss / heat dissipation resulting from those voltage drops. These things also affect effective capacity / ‘run time’ provided by the cell in that environment.
Does the algorithm of DCIR take account of conversion/difference between the AC and DC?
As far as I’m aware of / know, there exists no formula / equation for direct mathematical conversion or correlation between DCIR (simple resistance) and ACIR (complex impedance), so the correct specification / measurement must be used for calculations depending on the electrical environment the cells are used in
All of that aside for a moment, the documentation I’ve seen for the ‘Vapcell S4+ V3’ charger (which I downloaded from the link on this page https://www.vapcelltech.com/h-pd-194.html states this:
“The charger can measure the internal resistance (DC IR) of the battery intelligently, and automatically distribute the appropriate charging current or discharge current according to the internal resistance of the battery.”
I don’t believe the stated “DCIR” measurements provided by this charger are valid, as tested by HKJ, and apparently he did not either. I do not know if this defect has been corrected in the currently shipping units of this charger, but if not, hopefully it will be going forward. I also don’t believe this charger uses an AC test signal (nominally 2kHz), which would be required to measure cell impedance (which would not be “DCIR” anyway, as the manufacturer states the device measures). Measurement of impedance requires use of such an externally-applied AC test signal, which I don’t believe this product is capable of, and if so there should be no confusion about what is actually being measured. Chargers in this category generally use the output of the cell itself to perform this measurement, which obviously is DC.
A bit of a sweeping statement.
The two measurements indeed measure the same parameter, but using different methods. While the raw numbers cannot be directly compared, as I said they are definitely correlated. As an example, if either reading changes significantly over time it will indicate changes in the cells state of health (SOH).
Manufacturers use ACIR for screening cells because it does not depend on the cells state of charge (SOC), it is fast and accurate. If you want to check your cells for IR and want to use the data sheet numbers for the comparison, you need to use ACIR at 1Khz for it to be meaningful.
That being said, I have used DCIR for lots of years to track my cells SOH. It is a valid tool (and probably the best tool most have available to them) if you can find a device that gives you accurate and repeatable data. You just need to understand that the results depend heavily on the cells charge level and temperature.
I have been adding ACIR data to my spreadsheets over time. The numbers do correlate. Meaning if I am reading what are low IR readings using DCIR, they will also have low ACIR.
Anyway, check those links that I provided above for more insight.
Thought this might be good place to add a post. Looking at the Vapcell S4 Plus V3 for mostly charging Eneloop/ITSON AA and AAA cells. For those who have experience, how is the charger performing regards maximising capacity and also termination voltage. I noted some results seem to be in the 1.4x volt range upon completion. I use a SkyRC mostly but curious to potentially try a Vapcell unit.
The S4+ is a very good NiMH-charger, IMHO better than the Skyrc NiMH-only-chargers.
You will find chargers which put maybe 50-100mAh (depending on capacity) more in the cells but overall I would waive this, cooler and longer lasting cells are better for my working method.
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The S4+ v2 I have doesn’t do my AAA Nimh any favors. The lowest charge current is 250 mA which is too high and causes them to heat up during charging (not excessovely so, but still). The ideal current is 80-90 mA. Otherwise it charges to 1.45 to 1.51 volts when it terminates, but doesn’t trickle charge after that.
“What is the recommended charge current for Eneloops?
The recommended charge rate depends on the model and size. Have a look at all the product sheets on the overview page. There you will see the fast charge current. It`s better not to charge at a very low current because it is more difficult for the charger to recognize if a battery is full. My recommendations for manual chargers; (charge rate: 0.3C-1C). This is also the recommended charge rate by Maha / Powerex.
AA std= between 700mA and 2000mA
AA PRO= between 700mA and 2500mA
AA lite= between 300mA and 1000mA
AAA std= between 250 and 750mA
AAA PRO= between 300 and 1000mA
AAA lite= between 200 and 500mA
An Eneloop technician actually recommended charging with .5C – 1C. But if the charger is good enough, the lower charge current (about 1000mAh or lower ). Scroll down to understand what C means.”
Source: How to charge Eneloops? The Ultimate 2025 guide | Eneloop101.com
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Thanks @Johnny_Bravo and @Sirstinky for the replies. I agree on the less is more in some cases for charging capacity, the S4+ is still tempting me at this point, even if just to test and experiment with!
I have no issues charging my Eneloop AAA at 500mA to be honest, in fact I believe my MC3000 defaults to that, might even be 750mA, they don’t get hot at all, normally staying below 30-32 degrees. Of course it depends on the charger, how it manages the charge and temperature. From my understanding and as @Northman commented above, charging at below 250mA could risk a poor termination of charge.