Test/review of Vapcell U2

HKJ

Flashaholic
Joined
Mar 26, 2008
Messages
9,715
Location
Copenhagen, Denmark
[size=+3]Vapcell U2[/size]

DSC_1555.jpg


DSC_1556.jpg
DSC_1557.jpg


This is a universal charger from Vapcell, it can charger all battery sizes and the common chemistries. There is also a power bank output.




The charger arrived in a white cardboard box with specifications including a list of supported batteries.

DSC_1552.jpg


The box included the charger, a usb cable and a instruction sheet.

DSC_1559.jpg


The charger is USB powered and has a power bank function.



The user interface contains 2 buttons and a couple of leds.
The buttons can be used to select chemistry and current when putting batteries in the charger, but is locked during charge.
MODE: Select between 3.6V/3.2V, 4.2V/3.6 and 4.35V/3.8V charge voltage for LiIon.
CURRENT: Select between 0.5A, 1A and 2A for LiIon.
During charge a press on the MODE button will show the current chemistry.




The back has the usual specifications, in a easy readable color.

DSC_1562.jpg
DSC_1563.jpg


The connection are the common slider style that can handle from 33.5mm to 77mm, this handles all normal sizes of LiIon and NiMH cells, protected or not. Specified battery length is 34 to 75mm.

supportedBatteryTypes.png


supportedBatterySizes.png
DSC_1589.jpg
DSC_1590.jpg
DSC_1591.jpg


DSC_1592.jpg
DSC_1593.jpg
DSC_1594.jpg
DSC_1595.jpg
DSC_1596.jpg
DSC_1597.jpg
DSC_1598.jpg


The charge current is on the high side for 10440 cells.



[size=+2]Measurements charger[/size]

[index=16]


  • When not powered it will discharge a LiIon battery with about 1mA on USB channel and 0.03mA on the other.
  • When powered the charge will charge with about 0.5mA when finished.
  • With a shorted battery (i.e. 0V) the charger will report error by flashing the leds.
  • Between 0.1V and 1.7V the battery is assumed to be NiMH.
  • Above 2.0V the battery is assumed to be LiIon.
  • 2A current can only be used on one slot.
  • NiMH is always 0.5A charge current.
  • Charger will not restart if battery voltage drops.
  • Charger will restart if a nearly full battery in inserted or power cycled.
  • USB output only works on slot #2 (It is clearly marked).
  • Power consumption when idle is 33mA from USB.


[size=+1]Charging LiIon 4.2V[/size]

Vapcell%20U2%201A%20%28SA18650-33%29%20%231.png


The charger uses a nice CC/CV charge profile for LiIon with a termination current around 110mA.

Vapcell%20U2%201A%20%28SA18650-33%29%20%232.png


The second slot is similar.

Vapcell%20U2%201A%20%28SA18650-26%29%20%231.png

Vapcell%20U2%201A%20%28PA18650-31%29%20%231.png

Vapcell%20U2%201A%20%28BE18650-26%29%20%231.png


The 3 other batteries are also handled in a similar way.

Vapcell%20U2%200.5A%20%28SA18650-33%29%20%231.png


Using the low charge rate works fine.

Vapcell%20U2%200.5A%20%28KP14500-08%29%20%231.png


But with this cell there is a bump in the current (I did this two times and got a bump each time). The termination current is similar.

Vapcell%20U2%202A%20%28SA18650-33%29%20%231.png

Vapcell%20U2%202A%20%28SA20700-30%29%20%231.png


Charging a high current cell at 2A goes fairly fast.

Vapcell%20U2%201A%20%282xSA18650-33%29.png


Charging two LiIon cells at 1A works fine.

Vapcell%20U2%201A%200%2C5ohm%20%282xSA18650-33%29.png


Using a 0.5ohm resistor in series with the power supply to simulate a weak power supply or long cable slow down the charging. It also took some time before the charger settled on a slower charge rate. The end result is fine.

Temp7458.png


M1: 35.9°C, M2: 36.2°C, M3: 45.8°C, HS1: 51.7°C

Temp7459.png


M1: 48.6°C, M2: 42.9°C, HS1: 51.8°C

PoweronLiIon.png


The charger needs about 7 seconds to turn on, partly because it waits for user input.

Unpowered%20voltage%20sweep%20%231.png

Unpowered%20voltage%20sweep%20%232.png


The charge only slot do not load the battery when the charger is unpowered, but the USB output will draw some power to maintain the 5V output.

Charge%20Solar%20NiMH.png


The charger can work with a unstable supply, but it had some problems controlling the current when the voltage increased again and the charger restarts.



[size=+1]Charging LiIon 4.35[/size]

Vapcell%20U2%201A%20%28LG18650-30%29%20%231.png


The 4.35V charge curve is similar to the 4.2V charge curve, except for the higher voltage, it uses 4.4V instead of 4.35V, this is at the limit of the allowable range.



[size=+1]Charging LiFePO4 at 3.6V[/size]

Vapcell%20U2%201A%20%2818650-LiFePO4%29%20%231.png


Vapcell%20U2%200.5A%20%28SO14500-LiFePO4%29%20%231.png


This charger works fine, but uses 3.7V (This is acceptable).



[size=+1]Charging NiMH[/size]

Vapcell%20U2%200.5A%20%28eneloop%29%20%231.png


The NiMH charging uses the usually pulsing and the termination looks to be -dv/dt or 0dv/dt.

Vapcell%20U2%200.5A%20%28eneloopPro%29%20%231.png

Vapcell%20U2%200.5A%20%28fujitsu%29%20%231.png

Vapcell%20U2%200.5A%20%28leise25%29%20%231.png


With the high capacity cells it looks more like voltage termination on two of them.

Vapcell%20U2%200.5A%20%28eneloopAAA%29%20%231.png


The AAA cells is definitely a -dv/dt termination, but something is wrong with my cell, the capacity is too low or it was not empty when I started (This is not a charger problem, the termination is perfect).

Vapcell%20U2%200.5A%20full%20%28eneloop%29%20%231.png


The charger is, as expected, a bit slow to termination on a full cell.

Vapcell%20U2%200.5A%20%282xeneloop%29.png


Two cell is handled as fast as one cell.

Temp7464.png


M1: 38.5°C, M2: 39.8°C, M3: 44.5°C, HS1: 48.6°C

Temp7465.png


M1: 38.2°C, M2: 37.6°C, HS1: 42.9°C

PoweronNiMH.png


The charger uses the same start time for NiMH, but the user cannot change chemistry or current.

ChargeNiMH.png


As usually the charger is pulsing the charge current.

Charge%20Solar%20NiMH.png


NiMH also works with unstable supply and again the charger has a bit trouble with the current control during startup.



[size=+1]USB out[/size]

  • When not powered it will discharge a LiIon battery with about 1mA.
  • USB output do not turn off when unloaded.
  • USB output is coded as DCP.
  • USB output turns off when charger is powered.


Vapcell%20U2%20load%20sweep.png


The USB output can deliver about 1A, before it will reduce the voltage, overload protection kicks first in at about 1.5A

Vapcell%20U2%20usb%20out%2010ohm.png


At 0.5A the output is stable until the charger turns current off due to empty battery. This happens at around 3V.

Vapcell%20U2%20usb%20out%205ohm.png


The boost converter is a bit on the weak side for a 1A output and cannot maintain output voltage with 1A current load when the battery voltage drops.

10ohm.png


The noise is 6mV rms and 55mVpp with a 10ohm load.

5ohm.png


The noise is 11mV rms and 90mVpp with a 5ohm load, but values are very low.



[size=+2]Conclusion[/size]

The charger is a fairly simple model, but it can handle a wide variety of battery types and sizes and mostly it looks good. The 4.35V charge is slightly on the high side and during my test the second charge channel (USB output channel) died, maybe because I was a bit hard on the USB output (USB output did not die).
The power bank function is a bit weak, it has trouble maintaining 5V during the full time when drawing 1A

As a final rating I will call it fairly good.



[size=+3]Notes[/size]

The charger was supplied by a Vapcell for review.

Here is an explanation on how I did the above charge curves: How do I test a charger
 

Latest posts

Top