Charger Xtar VP4 Plus Dragon

DSC_6680
DSC_6682 DSC_6681

Xtar has many good LiIon chargers, this is the new top of line model. It can charge 4 round cell, a 3S battery pack and a smartphone, it can also measure capacity, or work as a power bank and it has a cell resistance and voltage meter.

DSC_3538 DSC_3539 DSC_3540 DSC_3541

It comes in a cardboard box (I got the charger without a box and the pictures is supplied by Xtar).

DSC_7268 DSC_7269

In the box is a bag that contains the charger and accessories, there is also an elastic strip to hold batteries.

DSC_7270

The contents of the bag is the charger, a power supply, the resistance (IR)/voltage probes, car charger, instruction sheet, welcome note and warranty card.

DSC_6678

The probes are four terminal and uses a usb connector. The 4 terminal connection means that it will automatic compensate for any wire resistance and connection resistance at the charger, but it cannot compensate for connection resistance at the battery with the supplied probes.

DSC_7224

The probes are spring loaded and has a rough surface to get better connection.

DSC_6684

The charger has a DC connector for power input, two usb connectors, one for the IR probes and one for power output. There is also a JST-XH connector to charge a 3S LiIon battery pack. Because the charger is "only" charging at 1A this function do not need the main connection to the battery pack.

DSC_6685

The charger has a large screen, four leds and 3 buttons:
Current/Refresh button: A short press will change current setting, a long press will start a refresh cycle.
Display: A short press will change between displayed slots (With 1 or 2 batteries the display will always show the correct slots), a long press will set the display to lowest brightness, a double click will return to main screen.
Record/Test: A short press will recall test data (The result of test runs is automatically saved), a long press will start a test cycle, a double click will turn sound on/off.
When showing recorded data the buttons has functions to step between records and delete records.
When display brightness is reduced the first keypress will restore it to full brightness.
The leds uses colors to show the functions:
Blue: Discharge, this is valid for both refresh/test and power bank function.
Red: Battery charging
Green: Battery full or slot empty
Off: Battery empty in power bank or power bank not turned on.

DSC_7131

Here is the full display captured during power on.

DSC_7134

Normal charging at 1A.

DSC_7135

Discharge during refresh mode, the blocks are animated to show that the charger is discharging.

DSC_7132 DSC_7133

When volt/ohm mode is enabled and the probes connected to a battery the display will change between ohm and volt.

DSC_7138

The 3S charging do not have much display space, only one icon, flashing while charging and steady when done.

DSC_6686 DSC_6687 DSC_6689

The charger uses the typical construction with a slider, this time with a very long connection at the plus pole making it possible to handle D and 32650 cells. The slots can handle from 30.5mm to 72.8mm.

supportedBatteryTypes

supportedBatterySizes
DSC_7086 DSC_7087 DSC_7088 DSC_7089

DSC_7090 DSC_7091 DSC_7092 DSC_7093

DSC_7094 DSC_7095 DSC_7096 DSC_7097


The charger can handle 70 mm long batteries, inclusive flat top cells.



Measurements


Lion charging

The LiIon charging can charge 4 cells with 0.5A or 1A and two cells with 2A.

Xtar%20VP4plus%201A%20%28PA18650-31%29%20%231

This is a good CC/CV charge curve with termination current around 80mA
Display shows 2916mAh

Xtar%20VP4plus%201A%20%28PA18650-31%29%20%232
Xtar%20VP4plus%201A%20%28PA18650-31%29%20%233
Xtar%20VP4plus%201A%20%28PA18650-31%29%20%234

The other slots are also fine. On #3 the charger starts reducing current a bit earlier for some reason.
Display shows: 2766mAh, 2860mAh, 2900mAh

Xtar%20VP4plus%201A%20%28SA18650-26%29%20%231
Xtar%20VP4plus%201A%20%28PA18650-34%29%20%231

The 2600 and 3400mAh cells are handled fine.
Display shows: 2599mAh and 3232mAh

Xtar%20VP4plus%201A%20%28BE18650-26%29%20%231

The old 2600mAh cell is mostly charged in CV mode (As expected), the charger handles it fine.
Display shows: 2253mAh

Xtar%20VP4plus%201A%20%28SA18650-33%29%20%231

I did get time for a single run with my new test cell, it works as expected.
Display shows: 3384mAh

Xtar%20VP4plus%200.5A%20%28PA18650-31%29%20%231

Charging with lower current will reduce the termination current to about 40mA (Good).

Xtar%20VP4plus%200.5A%20%28KP14500-08%29%20%231
Xtar%20VP4plus%200.5A%20%28AW18350-IMR%29%20%231

This works very well with the small cells.
Display shows: 717mAh and 488mAh

Xtar%20VP4plus%202A%20%282xAWT18650-30%29

The charger can charge two batteries at 2A, this is for larger cells and high current cells. The termination current is increased to about 120mA.

Xtar%20VP4plus%201A%20%284xPA18650-31%29

At 1A it is possible to charge four cells.
Display shows: 2918mAh, 2899mAh, 2917mAh, 2931mAh

Xtar%20VP4plus%201A%2012V%20%284xPA18650-31%29

Using my own 12V supply I can see it uses a bit below 2A when charging.

Temp3732

M1: 33,1°C, M2: 34,4°C, M3: 34,5°C, M4: 32,2°C, M5: 36,2°C, M6: 36,6°C, HS1: 49,2°C

Temp3733

M1: 33,5°C, M2: 35,1°C, M3: 35,2°C, M4: 33,4°C, M5: 42,1°C, M6: 36,0°C, HS1: 44,5°C

PowerOnLiIon

The charger needs about 8 seconds to initialize, before it will charge.

CurrentChangeLiIon

It is possible to change current at any time during a charger.



LiIon Refresh

The refresh function will discharge and charge a cell, the display will show both discharged and charged capacity.
The discharge current is either 0.25A or 0.5A, depending on selected charge current.

Xtar%20VP4plus%20refresh%201A%20%28PA18650-31%29%20%231

With 1A charge current the discharge current is 0.5A and the cell is discharged down to about 2.6V, this is fine for most modern cells. After the discharge there is a 5 minute rest, before the cell is charged again.
Display shows: dis:2916mAh, charge:2925mAh

Xtar%20VP4plus%20refresh%201A%20%28PA18650-31%29%20%232
Xtar%20VP4plus%20refresh%201A%20%28PA18650-31%29%20%233
Xtar%20VP4plus%20refresh%201A%20%28PA18650-31%29%20%234

The other 3 slots looks the same.
Display shows: dis: 2783mAh, 2840mAh, 2851mAh, charge: 2804mAh, 2872mAh, 2843mAh

Xtar%20VP4plus%20refresh%200.5A%20%28PA18650-31%29%20%231

With 0.5A charge current the discharge current is 0.25A.
Display shows: dis:2897mAh, charge:2946mAh

Xtar%20VP4plus%20refresh%202A%20%28PA18650-31%29%20%231

At 2A charge current the discharge current is 0.5A, i.e. the same as 1A discharge current.
Display shows: dis:2927mAh, charge:2942mAh

Xtar%20VP4plus%20refresh%201A%20%284xPA18650-31%29

It is possible to refresh four cells at a time.
Display shows: dis:2819mAh, 2962mAh, 2930mAh, 3051mAh, charge: 2929mAh, 2953mAh, 2974mAh, 2983mAh

Temp3754

M1: 38,3°C, M2: 40,5°C, M3: 39,6°C, M4: 36,0°C, M5: 46,7°C, M6: 44,8°C, HS1: 59,5°C
Discharging LiIon the charger needs to get rid of some heat. It handles it fine without a fan, the cells stays at an acceptable temperature.

DischargeLiIon

The discharge is done with constant current, not pwm (nice).



LiIon Test

The test mode will charge, discharge and charge again. Used discharge current is the same as in refresh mode.

Xtar%20VP4plus%20test%201A%20%28PA18650-31%29%20%231

Charging first means the full capacity is measured during discharge.
Display shows: dis:2873mAh, charge: 2885mAh



NiMH charging

Xtar%20VP4plus%201A%20%28eneloop%29%20%231

The charger starts with a low charge current (0.1A), before it switches to the selected current. On this charge curve it uses a voltage termination followed by a two hour top-off charge of around 50mA
Display shows: 1622mAh

Xtar%20VP4plus%201A%20%28eneloop%29%20%232
Xtar%20VP4plus%201A%20%28eneloop%29%20%233

With these two cells it uses a -dv/dt termination, but they still gets the top-off charge.

Xtar%20VP4plus%201A%20%28eneloop%29%20%234

And here is another voltage termination.

Xtar%20VP4plus%201A%20%28eneloopXX%29%20%231
Xtar%20VP4plus%201A%20%28eneloopPro%29%20%231
Xtar%20VP4plus%201A%20%28powerex%29%20%231

The 3 high capacity cells are handled fine. Termination is a bit slow on the worn down eneloopXX, but that is acceptable.
Display shows: 2597mAh, 2433mAh and 2449mAh

Xtar%20VP4plus%200.5A%20%28eneloop%29%20%231

It do also terminate at 0.5A on a AA cell.
Display shows: 1831mAh

Xtar%20VP4plus%200.5A%20%28eneloopAAA%29%20%231

No problems with the AAA cell. The top-off is still two hours, but with lower current (nice).
Display shows: 620mAh

Xtar%20VP4plus%202A%20%28eneloop%29%20%231

The 2A charge is also started at low current and looks fine.
Display shows: 1666mAh

Xtar%20VP4plus%201A%20full%20%28eneloop%29%20%231

Due to the first 10 minutes at low current it takes about 13 minutes to detect the full cell. This time on voltage, it will use longer time if it needs to use -dv/dt detection.
Display shows: 53mAh

Xtar%20VP4plus%201A%20%284xeneloop%29

Four cells at once.
Display shows: 1813mAh, 1719mAh, 1856mAh and 1793mAh

Xtar%20VP4plus%201A%2012V%20%284xeneloop%29

Using my own 12V power supply I can see the current drain is about 1A.

Temp3743

M1: 38,2°C, M2: 40,1°C, M3: 38,5°C, M4: 37,9°C, M5: 37,3°C, HS1: 48,6°C

PowerOnNiMH

The charger needs between 6 and 7 seconds to initialize a NiMH charge. The low current charge will last for 10minutes, before the charger switches to selected current.

CurrentChangeNiMH

It is possible to change current at any time. As usual with NiMH chargers the current is turned off for voltage checking.

TopOff0.5A

Top-off charge is done with pulses at the selected current. The top-off current will be about 6% of the selected charge current.

TopOff2A

Here is the 2A top-off pulses.



NiMH Refresh

Refresh mode will discharge and then charge the cell. Discharge current will depend on selected charge current.
0.5A charge means 0.25A discharge, 1A and 2A charge means 0.5A discharge.

Xtar%20VP4plus%20refresh%201A%20%28eneloop%29%20%231

The charger insist on doing the 10minutes low current charge, before starting on the discharge. The discharge is down to about 0.85 volt. After the discharge there is a 5 minute pause, before the battery is charged.
Display shows: dis:1921mAh, charge 1702mAh

Xtar%20VP4plus%20refresh%201A%20%28eneloop%29%20%232
Xtar%20VP4plus%20refresh%201A%20%28eneloop%29%20%233
Xtar%20VP4plus%20refresh%201A%20%28eneloop%29%20%234

Display shows: dis:1889mAh, 1846mAh, 1880mAH, 1877mAh, charge 1926mAh, 1692mAh, 1876mAh, 1665mAh

Xtar%20VP4plus%20refresh%200.5A%20%28eneloop%29%20%231

With 0.5A charge current the discharge current is 0.25A.
Display shows: dis:1931mAh, charge: 1926mAh

Xtar%20VP4plus%20refresh%202A%20%28eneloop%29%20%231

At 2A the discharge is 0.5A
Display shows: dis:1889mAh, charge: 1692mAh

Xtar%20VP4plus%20refresh%201A%20%284xeneloop%29

The charger can discharge four cells at once.
Display shows: dis:1904mAh, 1866mAh, 1919mAh, 1898mAh, charge: 1877mAh, 1863mAh, 1907mAh, 1891mAh

Temp3752

M1: 32,9°C, M2: 34,3°C, M3: 34,1°C, M4: 32,0°C, M5: 35,1°C, M6: 34,7°C, HS1: 43,4°C
The charger stays cool when discharging NiMH batteries.

DischargeNiMH

The discharge current at different charge settings.



NiMH test

The test will charge, discharge and charge again.

Xtar%20VP4plus%20test%201A%20%28eneloop%29%20%231

The charger do not use a top-off charge before discharging when terminated on voltage, this may give a slightly low capacity for some cells.
Display shows: dis:1868, charge: 1701




3S battery pack

The charger can also do a balancing charge on 3S battery packs with a JST-XH connector.
The charger do not use the main leads to the battery pack, only the balancing connector, this is acceptable due to the fairly low charge current (For a RC pack).

Xtar%20VP4plus%201A%20%283xSA18650-33%29%203S

The charger uses a 1A charge current and will do a CC/CV charge. It looks like there is a slight voltage difference between the charged cells (This test was done with new unused cells).

Xtar%20VP4plus%201A%201%20full%20%283xPA18650-31%29%203S

Here the battery pack contained 1 full cell and two empty cells. The charger balances them fine.

Charge3S

During charge the current is pulsed, probably to allow measuring without have trouble with wire resistance.



Internal resistance and voltage measurement

To start IR measurement the probes must be shorted, to leave IR mode double click the display button, the charger will also leave IR mode after about 10 minutes.
Due to the way the measurements are done the charger can only measure batteries, not resistors.

RILiIon

The above values is with LiIon cells, the result is a little bit on the low side, but very consistent.

RINiMH

With NiMH the results are a better, but due to the 150mOhm maximum I could not do the last row.

RImeasurement

The RI is measured with a short 1A current pulse

RIfrequency

A new measurement is done each 2.5 seconds.

The voltmeter function works from 0.66V to 4.49V and is within 0.01V

The probes must not be used on the batteries in the charger!



USB output

Xtar%20VP4plus%20%28PA18650-31%29%20load%20sweep

With a single 18650 battery I could draw about 2.2A before output voltage starts to drop. Output is switched off at 2.7A.

Xtar%20VP4plus%20%284xPA18650-31%29%20load%20sweep

With four batteries the output can be maintained up to 2.7A.

Xtar%20VP4plus%20%28ext.%20power%29%20load%20sweep

With external power it can also deliver 2.7A.

Xtar%20VP4plus%20usb%20out%2010ohm%20%284xPA18650-31%29

With four batteries it can maintain 0.5A output for about 11 hours.

Xtar%20VP4plus%20usb%20out%2010ohm%20%28PA18650-31%29

Using only one battery the time is down to 2½ hour.

Xtar%20VP4plus%20usb%20out%205ohm%20%284xPA18650-31%29

At 1A the output can be maintained for 6 hour.

Xtar%20VP4plus%20usb%20out%202.5ohm%20%284xPA18650-31%29

And at 2A it will maintain output for 3 hours.

Xtar%20VP4plus%20usb%20out%202.5ohm%20%28PA18650-31%29

With one battery it will maintain output, but not for very long.

Xtar%20VP4plus%20load%20test

With mains power and 2.5A out it did run for one hour.
The IR photos below are taken about 45 minutes into the one hour run.

Temp3746

M1: 39,8°C, M2: 37,2°C, M3: 45,5°C, HS1: 51,7°C

Temp3748

M1: 45,3°C, M2: 56,5°C, HS1: 92,9°C

Temp3749

M1: 51,4°C, HS1: 63,9°C


10ohm

As a power bank the usb output has very low noise, at 0.5A it is 8mV rms and 58mVpp.

5ohm

At 1A it is 13mV rms and 78mVpp.

2.5ohm

At 2A it is 27mV rms and 133mVpp

10ohmMains

The noise is also very low when mains powered. At 0.5A it is 25mV rms and 119mVpp.

5ohmMains

At 1A it is 23mV rms and 104mVpp.

2.5ohmMains

At 1A it is 20mV rms and 131mVpp.



Testing the transformer with 2830 volt and 4242 volt between mains and low volt side, did not show any safety problems.



Conclusion

This charger has many functions with a fairly simple user interface: It is a very good charger, but for some people it is probably for simplified.



Notes

The charger was supplied by Xtar for review.

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