Test/review of Charger Xtar VC2S

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HKJ
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Test/review of Charger Xtar VC2S

Charger Xtar VC2S
DSC_2769
DSC_2770 DSC_2771
Xtar makes many chargers, this is a usb powered dual channel charger with display. The charger can charge with up to 2A for a channel, the current will depend on the internal resistance in the batteries. It can also work as a power bank.
DSC_2763 DSC_2764 DSC_2765 DSC_2766
I got the charger in cardboard box with the specifications printed on it.
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n the box was the charger, a usb cable and a instruction sheet in many languages.
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The charger is usb powered from a micro usb connector and it has a power bank output.
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The user interface is a display, two leds and one button to select what the display shows or turn on the usb output.
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When powered on the display will show all segments, the needle will start from zero and increase, I took the photo before the last needle was displayed.
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Charging one battery, the red/green leds always make it easy to see if the charger is finished.
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One press on the the button and the display shows the actual charge current.
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After next press it shows the internal resistance in the batteries.
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When used as a power bank the display shows the usb voltage and current.
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The specifications are on the back of the charger, but you need light from the right angle to read it and maybe a magnifying glass.
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The charger can handle both button top and flat top batteries.
The slider moves smoothly and can hand cells from 30mm to 70.5mm long.
DSC_2776
The power bank function only uses one battery and the slot is marked.
supportedBatteryTypes
supportedBatterySizes DSC_3173 DSC_3174 DSC_3175
DSC_3224 DSC_3225 DSC_3176 DSC_3177 DSC_3178 DSC_3179 DSC_3180
The charger can handle 71 mm long batteries, including flat top cells.
The current for 10440 is on the high side even with the automatic regulation at minimum.
Measurements charger


  • Charger will use about 145mA from usb with display at full brightness and 32mA with display at low brightness.
  • When charging the last digit in the capacity displays will flash.
  • The charger will assume NiMH from 0V to 1.7V
  • From 1.8V the charger will assume LiIon
  • When charge is finished the charger will charge with 0.5mA for LiIon.
  • Charger will restart if voltage drops to 3.9 volt.
  • Charge will restart charging after power loss, or battery insertion.
  • When not connected to power it will drain about 1mA from a LiIon battery and 0.2mA from a NiMH battery.
  • Voltage dial will update after the charging is done.
  • Voltage dial is not very precise.
  • Charge current steps down if usb voltage drops too much and may step up if usb voltage recovers (Like when one slot is finished).
  • mAh display flashes “Full” when the corresponding battery is full.

Charging 4.2V LiIon
Xtar%20VC2S%20%28SA18650-33%29%20%231
This is a nice CC/CV charge curve with a termination around 100mA. The mAh display is rather optimistic.
Display shows 3437mAh 42mOhm
Xtar%20VC2S%20%28SA18650-33%29%20%232
Here the voltage is slightly higher and the termination is around 140mA
Display shows 3107mAh 47mOhm
Xtar%20VC2S%20%28SA18650-26%29%20%231
The 2600mAh battery looks similar
Display shows 2730mAh 50mOhm (Discharge test shows 2481mAh was charged into battery)
Xtar%20VC2S%20%28PA18650-31%29%20%231
This battery is older and has higher internal resistance, the charger reduces charge current.
Display shows 3214mAh 179mOhm
Xtar%20VC2S%20%28BE18650-26%29%20%231
It is the same with this battery.
Display shows 2515mAh 149mOhm
Xtar%20VC2S%20%28AP18650-26%29%20%231
This is a new 2600mAh high current battery and it is charged at 2A.
Display shows 2902mAh 50mOhm
Xtar%20VC2S%20%28SA20700-30%29%20%231
This larger cell is also charged at 2A
Display shows 3164mAh 20mOhm
Xtar%20VC2S%20%28KP14500-08%29%20%231
A 14500 cells is charged at low current.
Display shows 889mAh 146mOhm
Xtar%20VC2S%20%28AW18350-IMR%29%20%231
The same for my worn down 18350 cell.
Display shows 204mAh 146mOhm
Xtar%20VC2S%20%282xSA18650-33%29
With two batteries in the charger the current is reduced to 1A for each cell.
Display shows 3489mAh 63mOhm and 3112mAh 41mOhm
Xtar%20VC2S%200.5ohm%20%282xSA18650-33%29
Adding 0.5ohm in series with the power supply forced the charger to reduce the current, but the measurement circuit is affect by this resistor, the cell is not 4000mA or 5mOhm.
Display shows 4074mAh 5mOhm and 3456mAh 5mOhm
Temp6056
M1: 34.6°C, M2: 35.0°C, M3: 36.1°C, HS1: 44.1°C
Temp6057
M1: 37.5°C, HS1: 41.9°C
PoweronLiIon
The charger pulses the charger current when starting a charge, this is used to analyse the internal resistance.
Charging NiMH
Xtar%20VC2S%20%28eneloop%29%20%231
My eneloop has been used a lot and the internal resistance is a bit high, this means the charger uses a low charge current. It looks like the termination is on voltage and a bit before the cell is full.
Display shows 1851mAh 103mOhm
Xtar%20VC2S%20%28eneloop%29%20%232
The second channel is the same.
Display shows 1538mAh 125mOhm
Xtar%20VC2S%20%28eneloopPro%29%20%231
The eneloop pro is also the same.
Display shows 2403mAh 82mOhm
Xtar%20VC2S%20%28leise25%29%20%231
The Leise battery needs slightly lower voltage to be full and termination works much better here (A small temperature increase can be seen on the black line).
Display shows 2438mAh 67mOhm
Xtar%20VC2S%20%28eneloopAAA%29%20%231
The AAA cell also stops a bit before it is full.
Display shows 700mAh 202mOhm
Xtar%20VC2S%20full%20%28eneloop%29%20%231
Due to the voltage termination the charger is fast at detecting a full cell, it happens when it switches to full charge current.
Display shows 13mAh 81mOhm
Xtar%20VC2S%20%282xeneloop%29
The charger can handle two cells simultaneous.
Display shows 1719mAh 76mOhm and 1506mAh 73mOhm
Temp6070
M1: 29.6°C, M2: 30.1°C, HS1: 35.8°C
Temp6071
HS1: 36.4°C
PoweronNiMH
This looks similar to LiIon, but the charge current is very low.
PoweronNiMH2
Using a longer timescale it can be seen that the charger switches to full charge current after about 4 minutes.
ChargingNiMH
As usual the charge current is turned off at regular intervals to check charge voltage when charging NiMH.
Internal resistance
RILiIon
I wonder about the difference between the two channels, they are not calibrated the same when checking LiIon.
The actual measurement circuit is very consistent, but will give a too low value.
RINiMH
With the NiMH both channels gives similar value. Again the measurement circuit is very consistent, but actual value is too low.
USB output (Power bank)

  • USB voltmeter looks precise
  • When not connected to power it will drain about 1mA from a LiIon battery
  • Usual usb output will turn on automatic, and it can be forced with the switch.
  • Usb output is coded as USB charger (DCP)
  • Usb output will turn off after 40 seconds with less than 220mAh load.

USBmeter
When using the usb output the current is shown, it is not a super precise meter, but gives an good idea about the current draw.
Xtar%20VC2S%20load%20sweep
The power bank function is rated for 1A and can deliver about 1.4A with a full battery.
Xtar%20VC2S%20usb%20power%20load%20sweep
The usb output can also deliver current directly from the usb input, but there is no current limit (I stopped manually at 2.5A).
Xtar%20VC2S%20usb%20power%20%2B%20charge%20load%20sweep
Here I charge a battery at the same time and was drawing about 3.3A from the usb supply.
Efficiency will be low, because some of the energy is used to charge the battery, not for usb output.
Xtar%20VC2S%20usb%20out%2010ohm
Running the power bank with a 0.5A load it can maintain the output for about 3½ hours.
Xtar%20VC2S%20usb%20out%205ohm
At 1A the output is maintained about 2 hours, again with full voltage until the battery is empty.
The jump in efficiency at the start is when the display reduces background light.
10ohm
Noises is 47mV rms and 339mVpp
5ohm
Noises is 45mV rms and 360mVpp
Conclusion
The charger is good at charging LiIon, with NiMH it uses voltage termination without top-off charge and that means the batteries is charged slightly below full capacity.
The automatic current selection means that charge current is kept down at a fairly safe level.
This charger has a calibration problem on slot #1 for the mAh measurement, it shows way to much.
The usb output works fine and the display is nice, using only one cell means the output current is a bit on the low side.
I will rate it as fairly good.
Notes
The charger was supplied by XTAR for a review.
Here is an explanation on how I did the above charge curves: How do I test a charger

My website with reviews of many chargers and batteries (More than 1000): https://lygte-info.dk/

contactcr
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The voltage dial being not very precise is an understatement. It’s nearly useless. Otherwise, I really like this charger for its USB input, 2A x1 output, simple/bright display. Hopefully they can make a VC4S which is more refined and if it could support QC2/3/USB-C input that would be an ideal charger in my opinion.

TheIntruder
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Darn. I had high hopes for this one.

Unfortunately, it seems that while XTAR has given users what they want in terms of more informative displays, there seem to be bugs involved. I don’t completely trust the voltmeter on my TC2/ET1 either, which is disappointing since that was an important feature for me. The voltage/current/resistance algorithms in the newest chargers seem to be buggy.

If XTAR can product a charger with the good fundamentals it’s been known for, along with some measure of manual control/override, it would be quite attractive.

d_t_a
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The above mentions that only the left bay is used for the power bank function.

I checked out an Xtar VC2S and noticed that in my unit, I can use either the left slot or the right slot to power up the USB-out (powerbank function). Either my unit has a problem or something changed between revisions of the VC2S?

Using either left or right slot activates the USB-out powerbank function of the VC2S. (I wonder if both slots are used, is the load balanced for both batteries?)

If both slots are loaded with lithium-ion battery, I’m not sure but maybe it still only uses 1 slot for the powerbank function (whichever was placed first? or the left-slot?)

contactcr wrote:
The voltage dial being not very precise is an understatement. It’s nearly useless. Otherwise, I really like this charger for its USB input, 2A x1 output, simple/bright display. Hopefully they can make a VC4S which is more refined and if it could support QC2/3/USB-C input that would be an ideal charger in my opinion.

Xtar FB page has been announcing the VC4S which seems to have the features of the VC2S (IR testing, real-time charge current display) and the TC2 (capacity testing), and I think also QC2/3 input to power 4 bays. However, I haven’t seen definitive specs of it yet. Hoping to see it soon.

HKJ
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d_t_a wrote:
The above mentions that only the left bay is used for the power bank function.

I checked out an Xtar VC2S and noticed that in my unit, I can use either the left slot or the right slot to power up the USB-out (powerbank function). Either my unit has a problem or something changed between revisions of the VC2S?

I suppose something has change, I would not expect this text to be present in yours:

My website with reviews of many chargers and batteries (More than 1000): https://lygte-info.dk/

d_t_a
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HKJ wrote:
d_t_a wrote:
The above mentions that only the left bay is used for the power bank function.

I checked out an Xtar VC2S and noticed that in my unit, I can use either the left slot or the right slot to power up the USB-out (powerbank function). Either my unit has a problem or something changed between revisions of the VC2S?

I suppose something has change, I would not expect this text to be present in yours:
!https://lygte-info.dk/pic/Xtar/ChargerVC2S/DSC_2776.jpg!

The text is present on the left slot but not on the right slot. But powerbank function works with either slot of the VC2S.

d_t_a
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I notice something about this charger.

I tested a very old (very high resistance) Eneloop NiMh battery on the VC2S. Initially it will detect as NiMh and charge it as such, but within several seconds later, the display will switch to Li-Ion. It only occurs on my very old Eneloop and another very old high-resistance NiMh battery though.

Mishanchik
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My version of VC2S has an inscription on the left slot. At installation of 2 cells at first the battery in the left compartment is discharged, then in the right. Actually, if you read the manual for VC2S, which no one reads:
“Both slots can be used for charging devices. But it will discharge the battery in left slot preferentially by default.”

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As a result of using several months,* I can call this charger an AAA Ni-Mh killer*. If you take a new AAA LADDA 900mAh, then the charger shows a low internal resistance of 40mOhm and sets a charge current of 2A for one inserted cell. I have about 10 new AAA LADDA from IKEA, and all of them set a charging current of 2A. There is only one way out – to put 2 cells on charge at the same time, then a current of 1A is applied to each, which is also a lot.

Madeeon
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Mishanchik wrote:
As a result of using several months,* I can call this charger an AAA Ni-Mh killer*. If you take a new AAA LADDA 900mAh, then the charger shows a low internal resistance of 40mOhm and sets a charge current of 2A for one inserted cell. I have about 10 new AAA LADDA from IKEA, and all of them set a charging current of 2A. There is only one way out – to put 2 cells on charge at the same time, then a current of 1A is applied to each, which is also a lot.

Hi, have you tried with Panasonic Eneloops? I’m looking some 2 bay charger, to mainly use with NiMh and i liked this.

marcolopes
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Mishanchik wrote:
As a result of using several months,* I can call this charger an AAA Ni-Mh killer*. If you take a new AAA LADDA 900mAh, then the charger shows a low internal resistance of 40mOhm and sets a charge current of 2A for one inserted cell. I have about 10 new AAA LADDA from IKEA, and all of them set a charging current of 2A. There is only one way out – to put 2 cells on charge at the same time, then a current of 1A is applied to each, which is also a lot.

I was watching this review and confirmed exactly the same… https://youtu.be/wPF9LoOvYY0?t=415

What the hell was XTAR thinking? This is supposed to the the next step over the VC version!!! Instead it’s a let down :\