XTAR VX4 Charger Review
XTAR VX4 Charger⌗
- Specifications
- Introduction
- Charger in use
- Battery compatibility
- Dimensions
- User interface
- Tests
- Power supply
- Conclusion
- Product page
Specifications⌗
| Brand/model | XTAR VX4 |
|---|---|
| Channels | 4 |
| Input | USB-C PD 20W (12V/1.67A) |
| Cut-Off Current | ⩽150mA |
| Operating Temperature | -10 to 40℃ |
| Review date | August 2024 |
| Battery Type | Constant Charge Current | Cut-Off Voltage |
|---|---|---|
| 3.6V Li-ion | 3Ax1 / 2Ax2 / 1Ax4 / 0.5Ax4 / 0.25Ax4 | 4.2±0.05V |
| 1.5V Li-ion | 0.5Ax4 | N/A |
| 3.2V LiFePO4 | 3Ax1 / 2Ax2 / 1Ax4 / 0.5Ax4 / 0.25Ax4 | 3.65±0.05V |
| 1.2V Ni-MH | 0.5Ax4 | 1.45±0.1V |
Introduction⌗
The XTAR VX4 is a four channel charger with charging and grading modes. It supports 3.6V Li-ion, 1.5V Li-ion, 1.2V Ni-MH and 3.2V LiFePO4. USB-C PD (12V/1.67A) input is recommended.
The VX4 is a bigger and better version of the XTAR MX4.
Some of the improvements include: a large display, a grading mode, and the ability to select the maximum charging current for 3.6V Li-ion and 3.2V LiFePO4 cells (0.25A, 0.5A, 1A, 2A, 3A).
I posted an interactive review of the XTAR VX4 on BLF.
XTAR kindly sent this charger for review. I have not been paid for this review nor have I held back my opinions of this charger.
Packaging⌗
The XTAR VX4 SET comes in a white and blue box with XTAR branding.
The following is included in the box:
- XTAR VX4
- XTAR USB-C PD 20W Power Supply
- USB-C to USB-C cable
- User manual
I received a digital copy of the user manual with this early sample. I later received an 18th anniversary edition of the VX4 with a printed user manual.
Charger in use⌗
The XTAR VX4 has three buttons, four channels to charge or grade four cells at a time, and a big display.
The sliders move relatively smoothly when inserting batteries. The springs feel tight.
The positive and negative terminals have notches to allow flat top and slightly recessed cells to be used.
There are ventilation holes on the bottom of the charger.
Four plastic feet on the bottom help with ventilation.
Battery compatibility⌗
The following cells are supported:
| Battery Type | Sizes |
|---|---|
| 1.2V Ni-MH | AAA, AA, A, SC, C, D |
| 1.5V Li-ion | AAA, AA |
| 3.6V Li-ion, 3.2V LiFePO4 | 10440, 14500, 14650, 16340, 17335, 17500, 17670, 18350, 18490, 18500, 18650, 18700, 20700, 21700, 22650, 25500, 26650, 32650 |
I was able to charge an 18350 with a recessed top, a flat top 10440, a button top 16340 and a flat top 26800.
The two outer channels are slightly wider compared to the two inner channels. This prevents four 26800 cells from fitting side-by-side.
Dimensions and weight⌗
Dimensions⌗
I took the following measurements using a digital caliper.
| Measurement | Unit (mm) |
|---|---|
| Charger height | 42.73 |
| Charger width | 128.78 |
| Charger length | 172.06 |
| Shortest cell length | 30.4 |
| Longest cell length | 80 |
Weight⌗
I took the following measurements using a digital scale.
| Weight | Unit (g) |
|---|---|
| XTAR VX4 | 315 |
User interface⌗
I highly recommend reading the user manual for a more details about the user interface.
The XTAR VX4 has three buttons and a display.
Buttons:
- C/V
- MODE
- mWh/mAh
When power is connected and each channel is empty, the C/V button can be clicked to change between:
- Standard Charging Mode (Ni-MH/Li-ion)
- LiFePO4 Charging Mode
The MODE button can be pressed and held to change between Grade and Charge modes.
The MODE button can be clicked to show more information (e.g. charging current, capacity).
The mWh/mAh button can be clicked to switch between displaying the capacity in mWh and mAh during the discharge stage while grading 1.5V Li-ion cells.
The mWh/mAh button can be pressed and held to turn the backlight for the display off.
A discharge current of 300mA is applied when grading a cell. The display will show 0300mA.
A - (minus) symbol is does not appear next to the current (e.g. 0300mA) to indicate that a discharge current of 300mA is being applied. Instead, a battery icon indicates whether a cell is being charged or discharged by gradually filling up or by becoming empty.
5V/430mA is supplied when charging a 1.5V Li-ion cell.
Tests⌗
Room temperature: 12 C
I have measured the voltage, current and temperature of various 1.5V Li-ion, 1.2V Ni-MH and 3.6V Li-ion cells while using the Grade and Charge modes of the XTAR VX4.
The voltage was measured with a Zoyi ZT-300AB Digital Multimeter.
The temperature was measured with a Type K thermocouple.
The current was calculated by measuring the voltage across a shunt with another Zoyi ZT-300AB Digital Multimeter.
I have not calibrated my equipment so the accuracy could be slightly off.
The shunt that I used may have caused the internal resistance measured by the XTAR VX4 to be higher than normal. This could result in the XTAR VX4 reducing the charging current (e.g. if I select 3000mA, the VX4 might reduce the charging current to 500mA if the internal resistance appears to be high).
| Mode | Chemistry | Cell | Top | Link |
|---|---|---|---|---|
| Grade | 1.5V Li-ion | XTAR AA 1.5V Li-ion 2500mAh | Button | Results |
| Grade | 1.5V Li-ion | XTAR AA 1.5V Li-ion 2500mAh | Button | Results |
| Grade | 3.6V Li-ion | XTAR 16340 3.6V Li-ion 850mAh | Button | Results |
| Grade | 3.6V Li-ion | XTAR 18650 3.6V Li-ion 4000mAh | Button | Results |
| Grade | 3.6V Li-ion | XTAR 18650 3.6V Li-ion 4000mAh | Button | Results |
| Grade | 3.6V Li-ion | Sanyo NCR18650GA Li-ion 3500mAh | Flat | Results |
| Grade | 3.6V Li-ion | NEXTORCH 16340 3.6V Li-ion 800mAh | Button | Results |
| Grade | 3.6V Li-ion | TrustFire 16340 3.7V Li-ion 650mAh | Button | Results |
| Grade | 3.6V Li-ion | XTAR 16340 3.6V Li-ion 850mAh | Button | Results |
| Grade | 3.6V Li-ion | XTAR 16340 3.6V Li-ion 850mAh | Button | Results |
| Grade | 3.6V Li-ion | XTAR 26650 3.6V Li-ion 6000mAh | Flat | Results |
| Grade | 1.2V Ni-MH | LADDA AA Ni-MH 2450mAh | Button | Results |
| Grade | 1.2V Ni-MH | 4*LADDA AAA Ni-MH 750mAh | Button | Results |
| Charge | 1.5V Li-ion | XTAR AA 1.5V Li-ion 2500mAh | Button | Results |
| Charge | 3.6V Li-ion | XTAR 16340 3.6V Li-ion 850mAh | Button | Results |
| Charge | 3.6V Li-ion | XTAR 18650 3.6V Li-ion 4000mAh | Button | Results |
| Charge | 3.6V Li-ion | Sanyo NCR18650GA Li-ion 3500mAh | Flat | Results |
| Charge | 3.6V Li-ion | XTAR 26650 3.6V Li-ion 6000mAh | Flat | Results |
| Charge | 3.6V Li-ion | XTAR 26650 3.6V Li-ion 6000mAh | Flat | Results |
| Charge | 3.6V Li-ion | Molicel P45B 21700 3.6V Li-ion 4500mAh | Flat | Results |
| Charge | 1.2V Ni-MH | LADDA AA Ni-MH 2450mAh | Button | Results |
| Charge | 1.2V Ni-MH | LADDA AA Ni-MH 2450mAh | Button | Results |
Grade CH1 1.5V Li-ion #1⌗
CH1: XTAR AA 1.5V Li-ion 2500mAh (button top) (dark blue)
| Measurement | CH1 | CH2 | CH3 | CH4 |
|---|---|---|---|---|
| Start Voltage | 1.510 | |||
| Finish Voltage | 1.509 | |||
| Capacity (mAh) | 2453 |
Before starting this test, I charged the 1.5V Li-ion cell, took the cell out, selected Grade mode, and put the cell back in.
The graph shows what the XTAR VX4 did while using Grade mode:
- Charge the cell at roughly 4.9V 0.5A for a few minutes.
- Discharge the cell at 0.3A for a 8 hours. A capacity of 2453mAh was measured (pretty good for a cell rated 2500mAh while the room was about 9 C).
- Charge the cell again at roughly 4.9V 0.5A for 3 hours.
Grade CH1 1.5V Li-ion #2⌗
CH1: XTAR AA 1.5V Li-ion 2500mAh (button top) (dark blue)
| Measurement | CH1 | CH2 | CH3 | CH4 |
|---|---|---|---|---|
| Start Voltage | 1.510 | |||
| Finish Voltage | 1.510 | |||
| Capacity (mAh) | 2478 | |||
| Capacity (mWh) | 3566 |
The capacity listed on the wrap of a XTAR AA 1.5V Li-ion 2500mAh (button top) (dark blue) cell is 2500mAh / 4150mWh.
2500mAh at 1.5V should be around 3750mWh.
Grade CH1 3.6V Li-ion #1⌗
CH1: XTAR 16340 3.6V Li-ion 850mAh (button top)
| Measurement | CH1 | CH2 | CH3 | CH4 |
|---|---|---|---|---|
| Start Voltage | 4.176 | |||
| Finish Voltage | ? | |||
| Capacity (mAh) | ? |
The XTAR VX4 continued to discharge and charge the protected XTAR 16340 cell.
I suspect that the protection circuit of the cell may have Over Voltage Protection (OVP) where it temporarily cuts out at around 4.21V. The XTAR VX4 stops charging the cell. OVP of the cell resets. The XTAR VX4 detects the cell as a newly inserted cell and then it repeats Grade mode.
Grade CH1 3.6V Li-ion #2⌗
CH1: XTAR 18650 3.6V Li-ion 4000mAh (button top)
| Measurement | CH1 | CH2 | CH3 | CH4 |
|---|---|---|---|---|
| Start Voltage | 4.202 | |||
| Finish Voltage | ? | |||
| Capacity (mAh) | ? | |||
| Capacity (mWh) | ? |
I tried Grade mode for an XTAR 18650 3.6V Li-ion 4000mAh cell and it continued to repeat the Charge-Discharge-Charge cycle.
The current cut out for a minute when the voltage reached 4.213V at the end of the first Charge-Discharge-Charge cycle (shortly after 12 hours). The VX4 then started discharging again at around 290mA.
I tried Grade mode again and it worked properly.
CH1: XTAR 18650 3.6V Li-ion 4000mAh (button top)
| Measurement | CH1 | CH2 | CH3 | CH4 |
|---|---|---|---|---|
| Start Voltage | 4.206 | |||
| Finish Voltage | 4.130 | |||
| Capacity (mAh) | 3993 |
The VX4 successfully measured the capacity of the XTAR 18650 4000mAh cell. It displayed “done” and stopped. The capacity measured was 3993mAh.
Grade CH1 3.6V Li-ion #3⌗
CH1: Sanyo NCR18650GA Li-ion 3500mAh (flat top)
| Measurement | CH1 | CH2 | CH3 | CH4 |
|---|---|---|---|---|
| Start Voltage | 4.196 | |||
| Finish Voltage | 4.143 | |||
| Capacity (mAh) | 3320 |
I selected 3000mA but the VX4 charged at 1000mA. The internal resistance of the cell might be too high and the XTAR VX4 has decided to use 1000mA.
Grade CH1 3.6V Li-ion #4⌗
CH1: NEXTORCH 16340 3.6V Li-ion 800mAh (button top)
| Measurement | CH1 | CH2 | CH3 | CH4 |
|---|---|---|---|---|
| Start Voltage | 4.169 | |||
| Finish Voltage | 4.097 | |||
| Capacity (mAh) | 796 |
Grade worked OK for a protected NEXTORCH 16340 3.6V Li-ion cell.
Grade CH1 3.6V Li-ion #5⌗
CH1: TrustFire 16340 3.7V Li-ion 650mAh (button top)
| Measurement | CH1 | CH2 | CH3 | CH4 |
|---|---|---|---|---|
| Start Voltage | 4.194 | |||
| Finish Voltage | 4.138 | |||
| Capacity (mAh) | 684 |
Grade worked properly with a TrustFire 16340 Li-ion cell. The Charge-Discharge-Charge cycle stopped and it did not restart after an hour and a half.
Grade CH1 3.6V Li-ion #6⌗
CH1: XTAR 16340 3.6V Li-ion 850mAh (button top)
| Measurement | CH1 | CH2 | CH3 | CH4 |
|---|---|---|---|---|
| Start Voltage | 4.196 | |||
| Finish Voltage | ? | |||
| Capacity (mAh) | ? |
I tried Grade mode for an XTAR 16340 3.6V Li-ion 850mAh cell again and it continued to repeat the Charge-Discharge-Charge cycle.
The current cut out for a minute when the voltage reached 4.212V at the end of the first Charge-Discharge-Charge cycle (shortly after 6 hours). The VX4 then started discharging again at around 290mA. I wonder if the protection circuit of the cell caused the cut out.
Grade CH1 3.6V Li-ion #8⌗
CH1: XTAR 16340 3.6V Li-ion 850mAh (button top)
| Measurement | CH1 | CH2 | CH3 | CH4 |
|---|---|---|---|---|
| Start Voltage | 4.140 | |||
| Finish Voltage | 4.097 | |||
| Capacity (mAh) | 833 |
Grade mode worked normally when the initial voltage of the XTAR 16340 cell was 4.14V and the internal resistance was low.
Grade CH1 1.2V Ni-MH #1⌗
CH1: LADDA AA Ni-MH 2450mAh (button top)
| Measurement | CH1 | CH2 | CH3 | CH4 |
|---|---|---|---|---|
| Start Voltage | 1.433 | |||
| Finish Voltage | 1.452 | |||
| Capacity (mAh) | 2474 |
Grade mode worked properly with a Ni-MH battery.
Grade CH1 1.2V Ni-MH #2⌗
4*LADDA AAA Ni-MH 750mAh (button top)
| Measurement | CH1 | CH2 | CH3 | CH4 |
|---|---|---|---|---|
| Capacity (mAh) | 721 | 726 | 728 | 702 |
Grade CH1 3.6V Li-ion #7⌗
CH1: XTAR 26650 3.6V Li-ion 6000mAh (flat top)
| Measurement | CH1 | CH2 | CH3 | CH4 |
|---|---|---|---|---|
| Start Voltage | 4.102 | |||
| Finish Voltage | 4.175 | |||
| Capacity (mAh) | 6174 |
The XTAR VX4 discharged an XTAR 26650 6000mAh cell at a rate of 280mA and it measured a capacity of 6174mAh.
This was very close to the Atorch DL24 where it discharged the same cell at a rate of 280mA and measured a capacity of 6163mAh.
Atorch DL24 Discharge 3.6V Li-ion⌗
I discharged an XTAR 26650 3.6V Li-ion 6000mAh (flat top) with an Atorch DL24 at a rate of 5A to measure the capacity.
| Measurement | CH1 | CH2 | CH3 | CH4 |
|---|---|---|---|---|
| Start Voltage | 4.199 | |||
| Finish Voltage | 3.355 | |||
| Capacity (mAh) | 5791 |
I discharged an XTAR 26650 3.6V Li-ion 6000mAh (flat top) with an Atorch DL24 at a rate of 0.28A to measure the capacity. It took 22 hours.
| Measurement | CH1 | CH2 | CH3 | CH4 |
|---|---|---|---|---|
| Start Voltage | 4.204 | |||
| Finish Voltage | 3.099 | |||
| Capacity (mAh) | 6163 |
Charge CH1 1.5V Li-ion #1⌗
CH1: XTAR AA 1.5V Li-ion 2500mAh (button top) (dark blue)
| Voltage | CH1 | CH2 | CH3 | CH4 |
|---|---|---|---|---|
| Start | 1.100 | |||
| Finish | 1.509 |
Charge CH1 3.6V Li-ion #1⌗
CH1: XTAR 16340 3.6V Li-ion 850mAh (button top)
| Voltage | CH1 | CH2 | CH3 | CH4 |
|---|---|---|---|---|
| Start | 3.152 | |||
| Finish | 4.113 |
Charge CH1 3.6V Li-ion #2⌗
CH1: XTAR 18650 3.6V Li-ion 4000mAh (button top)
| Voltage | CH1 | CH2 | CH3 | CH4 |
|---|---|---|---|---|
| Start | 3.043 | |||
| Finish | 4.154 |
Something odd happened halfway through the charging process. I suspect that the connection was a bit loose due to the shunt that I used.
Charge CH1 3.6V Li-ion #3⌗
CH1: Sanyo NCR18650GA 18650 Li-ion 3500mAh (flat top)
| Voltage | CH1 | CH2 | CH3 | CH4 |
|---|---|---|---|---|
| Start | 3.150 | |||
| Finish | 4.147 |
Charge CH1 3.6V Li-ion #4⌗
CH1: XTAR 26650 3.6V Li-ion 6000mAh (flat top)
| Voltage | CH1 | CH2 | CH3 | CH4 |
|---|---|---|---|---|
| Start | 3.401 | |||
| Finish | 4.160 |
I selected 3000mA but the VX4 used 500mA. The internal resistance of the cell might be a bit high.
Charge CH1 3.6V Li-ion #5⌗
CH1: Molicel P45B 21700 Li-ion 4500mAh (flat top)
| Voltage | CH1 | CH2 | CH3 | CH4 |
|---|---|---|---|---|
| Start | 3.627 | |||
| Finish | 4.177 |
3000mA charging. IR was ok.
Charge CH1 3.6V Li-ion #6⌗
CH1: XTAR 26650 3.6V Li-ion 6000mAh (flat top)
| Voltage | CH1 | CH2 | CH3 | CH4 |
|---|---|---|---|---|
| Start | 3.907 | |||
| Finish | 4.165 |
I selected 3000mA and the VX4 charged at 2000mA. The internal resistance might have been high.
Charge CH1 1.2V Ni-MH #1⌗
CH1: LADDA AA Ni-MH 2450mAh (button top)
| Voltage | CH1 | CH2 | CH3 | CH4 |
|---|---|---|---|---|
| Start | 1.179 | |||
| Finish | 1.493 |
The VX4 applied 150mA initially during the identification/activation stage and then the charging current went up to 500mA. It looks like -dV/dt or 0dV/dt termination has been used.
Charge CH1 1.2V Ni-MH #2⌗
CH1: LADDA AA Ni-MH 2450mAh (button top)
| Voltage | CH1 | CH2 | CH3 | CH4 |
|---|---|---|---|---|
| Start | 1.470 | |||
| Finish | 1.450 |
I charged a fully charged cell to see what would happen.
The VX4 applied a current of about 150mA for about 10 minutes (identification/activation stage) and then it trickle charged for 2 hours.
There is a gap in the graph where Bluetooth connectivity dropped for about 30 minutes while measuring the current.
Power supply⌗
I checked compatibility with the following power supplies:
| Power supply | USB Type | Protocol | Does it charge? |
|---|---|---|---|
| Apple 61W Power Adapter | USB-C | PD | Yes |
| PinePower Desktop | USB-C | PD | Yes |
| PinePower Desktop | USB-A | QC | Yes |
| PinePower Desktop | USB-A | Yes | |
| XTAR USB-C PD 45W Power Adapter | USB-C | PD | Yes |
XTAR recommend using a USB-C PD (12V/1.67A) power supply.
USB-C QC3 (9V/2A) and USB-C 5V/2A will work but the charging current might be limited.
XTAR 18th Anniversary⌗
Happy 18th Anniversary XTAR!
Conclusion⌗
The XTAR VX4 is one of the best battery chargers available right now that supports charging and grading of 1.5V Li-ion, 3.6V Li-ion, 3.2V LiFePO4 and 1.2V Ni-MH cells.
It is massive. I wish it had a few fans, the ability to charge all four channels at 3A, and the ability to discharge all four channels at 1A. It is limited to charging one channel at 3A, and the Grade mode is limited to a 300mA discharge current.
The user interface is pretty intuitive.
The ability to charge and grade 1.5V Li-ion cells is one of the main features of the XTAR VX4 that sets it apart from the competition.
If you do not want to measure the capacity of 1.5V Li-ion cells but want to simplify your chargers into one small four channel charger then the XTAR MX4 is a good option.
I recommend the XTAR VC8S, Vapcell S4 Plus, SkyRC MC3000 and Gyrfalcon S8000 if you are looking for battery chargers with a lot of features.
Pros:⌗
- Ability to select the maximum charging current for 3.6V Li-ion and 3.2V LiFePO4 cells.
- Measure cell capacity with Grade mode.
- Support for multiple battery chemistries and sizes.
- Easy to read display.
- Display backlight can be turned off.
Cons:⌗
- Massive size.
- Discharge current is limited to 300mA.
Price⌗
The XTAR VX4 SET is AU$75.85 from xtardirect.com