In my 8 and a half years as a vaper, I have always heard of Xtar as one of the best brands when it comes to battery chargers. Two years ago, for this reason, I purchased an XTAR MC4S, which is still working perfectly with its simplicity and efficiency.
I can proudly say that I had the opportunity to collaborate with Xtar, who kindly sent me the charger in question,
free of charge, without having any business relationship with them, affiliate links, or receiving any payment.
The Visible Mixer VX4, despite its name giving the impression of being something complex, is actually designed to be extremely simple, as it operates with only three buttons. However, compared to previous models, it offers additional features and conveniences that seem to be tailored specifically for vapers, even though we are not exactly the primary target.
As a charger, it goes well beyond the usual 26700 cells, which are the maximum supported by most chargers available in vape shops. The VX4, in fact, can also accommodate 32650 batteries, a format not commonly used by vapers but useful for flashlights, power banks, and other devices.
In addition, thanks to a different slot design, it can also handle standard AAA and AA batteries, along with other formats that I will list later—hence the name "Visible Mixer".
The VX4 comes in a rigid white cardboard box, featuring various specifications that I will explain, and on the back, there is a scratch-and-check verification label.
As proof that it is designed not only to sit on a shelf or desk, the Visible Mixer VX4 comes with a convenient carrying bag that also protects it from dust.
Included in the package are the warranty and user manual, where the Italian language is also present, as shown in the photos.
In my edition, a 20W PD power adapter is also provided, which Xtar recommends using. I will discuss this further later, along with its cable.
Illustrative photo to give an idea of the "real" dimensions, which are significantly larger than the usual two-slot or even four-slot chargers. The dimensions are L 172 × W 130 × H 41.5 mm.
Although mentioning "portability" might seem ironic given its size, the VX4 is designed to be the only charger one might need—from camping trips to a summer house—since it supports a wide range of battery formats. Its size is due not only to its features but also to its compatibility with 32650 cells. Additionally, beyond Li-ion batteries, it also charges Ni-MH:
3.6/3.7V Li-ion & 3.2V LiFeP04: 10440/14430/14500/14650/16340/17335/17500/17670/18350/18490/18500/18650/18700/20700/21700/22650/25500/26650/32650
1.5V Li-ion:AAA/AA
1.2V Ni-MH: AAA/AA/A/SC/C/D
A first overview of the display, proportionate to the size of the Visible Mixer VX4, and its 3 operational buttons that control everything.
The display in renders is shown with a blue light, and it appears the same in real life: considering its size, it could almost be considered a nightlight as it illuminates a good portion of a room. However, it is possible to completely turn off the display during charging, with no light or other LEDs shining.
This can be considered the "home" screen when charging 4 different batteries, though it is not the only one, as I will explain the various functions later.
The first difference compared to entry-level chargers is the ability to see the voltage and how many mA are being used for charging.
Also important are the only 3 operational buttons: C/V, Mode, and mWh/mAh.
The first "task" the VX4 removes from the user is immediately diagnosing the batteries, and it communicates this as well, as on the right side of each cell on the display, the information is specified.
There are two charging modes, depending on the battery. For vaping, the commonly used batteries, namely Li-ion in any format, follow a 3-phase charging process summarized with the TC/CC/CV acronym:
- TC - Trickle Charge: If the battery is very discharged (below 3V), a very low current is used to bring it to a safe level and prepare the cell for the actual charge.
- CC - Constant Current: After TC, the battery is charged with a constant current up to 4.2V, which is the actual charging process.
- CV - Constant Voltage: When the battery reaches 4.2V, the VX4 maintains a constant voltage and gradually reduces the current to zero, stopping the charge, with a chipset to avoid overcharging, similar to box mods and pods.
It is important to note that this is not an exclusive feature of the VX4, and even some more "entry-level" chargers have it, but it should still be mentioned. Usually, a battery falls below 3V after being left discharged for a long time. Box mods for vaping generally display Low Voltage warnings around 3.4V or 3.3V. Ni-MH batteries, on the other hand, use the CSVA Tech due to their different chemistry and precautions.
C/V Button:
- 1 click to change the charging mA (2000, 1000, 500, 250 mA available)
- Hold the C/V button to switch between Standard mode (3.6/3.7V Li-ion, 1.5V Li-ion, 1.2V Ni-MH) and LifePO4 mode (3.2V LiFePO4, 1.5V Li-ion, 1.2V Ni-MH)
A brief explanation on what might be the most intimidating aspect of the charger, as there’s a risk of making mistakes, but there’s no need to worry. For the Li-ion batteries commonly used by us, regardless of their format (18650, 21700, or even the smaller 18350), just leave it in Standard mode. If you do experiment with settings, there are protections (which I’ll explain later) to prevent any damage to the VX4 and the batteries.
Regarding the charging mA: the first feature that distinguishes the VX4 from other entry-level chargers costing around 20 euros is the option to charge batteries at only 250 mA, compared to the "standard" 500 mA. The slower the battery is charged, the less heat and stress is generated, thus preserving its lifespan both in terms of how long it holds a charge and how many mAh it can accumulate. This is especially beneficial for smaller batteries, like the 18350. The benefits over time become even more significant when charging consistently at 250 mA, and it’s even better to purchase new batteries and charge them exclusively at this rate.
To charge at 250 mA, you need only one battery inserted (unlike commercial chargers, where you need to fill all the slots to charge at 500 mA, otherwise it charges at 1000 mA). It’s also worth noting that the charging mA setting applies to all 4 slots: if I charge one battery at 250 mA and want to charge another at 500 mA, I’ll have to wait until the 250 mA charge finishes before inserting the second battery.
Mode Button:
- 1 click to switch from displaying the charging current to the charging capacity
- Hold the button to switch from Charge mode (CHG) to Capacity Measurement mode (GRAD.)
- Hold both C/V + Mode buttons together to switch to capacity measurement (GRAD.) for LiFePO4 batteries
While displaying the current or charging capacity is useful, the capacity reading is often enough to see how many mAh have been charged into the cell (but it doesn't account for how much charge was in the battery when inserted). For true diagnostics, there’s the Capacity Measurement mode (GRAD.). This is far more accurate, as the VX4 discharges the battery at 300 mA and then recharges it to its full capacity, with 95% accuracy compared to professional machines. The (GRAD.) mode, after the 250 mA setting, is the second major reason to buy the VX4: a feature completely absent in entry-level chargers. Unfortunately, it takes some time (with my newer 18650 3000 mAh batteries, it took over 20 hours to finish the diagnostic). Thankfully, you can "grade" 4 batteries at once, and depending on how many batteries you have, it typically takes 2 or 3 days. Also, for us vapers, there’s no need to set the LiFePO4 mode since we use Li-ion; just hold the button when (GRAD.) appears, and the VX4 handles everything.
mWh / mAh Button:
- 1 click to switch from displaying mAh to mWh (for 1.5V Li-ion batteries, it should only be done when they are in the discharge phase, which isn't our main concern)
- Hold to turn off the screen, and the VX4 continues charging
Less complicated than the other two, in most cases, you press it to turn off the display (which is extremely bright). Despite the initial complexity, especially for things that aren’t clearly understood, everything can be set with just 2 or 3 clicks.
Low-Voltage Recovery: a "secret" function that isn’t manually set, but is activated by the VX4 when necessary. This feature is designed exclusively for damaged batteries. Through micro-activations, batteries that are not detected by other chargers should (depending on what happened to them) be revived.
Protections: Finally, there are protections similar to those found in box mods, some of which I’ve already mentioned, while others are easily understood since we’ve always used them:
- Overcurrent Protection
- Overcharge Protection
- Overvoltage Protection
- Short-Circuit Protection
- Reverse Polarity Protection
- Temperature Protection
The movement for all four, presumably regulated by a spring, is very smooth. There's no need to apply the same force used with regular chargers, as it is designed to accommodate AA and AAA batteries, which are smaller and thinner than 18650.
The spring contact travel is so close, whereas in chargers that don't support AA and AAA, the contact travel starts about halfway.
The two central slots are slightly closer together. This becomes even more evident when placing two 21700 batteries in the center and two 18650 batteries on the sides. It's not a flaw for us, but I imagine extracting four 26650 batteries might be a bit inconvenient.
On the sides, there's a groove that helps when charging four batteries and you need to first remove one of the two outer ones. The grooves are not ventilation holes but rather a heat dissipation feature and something to grip the VX4 more securely, similar to some designs found on our atomizers.
The VX4 has a USB Type-C port on the top side for power supply. Included is a common USB Type-C cable to connect the VX4 to power, while the adapter is more "specific." It is a product that Xtar also sells separately, called PD 20W, and recommends using it as much as possible with its products since it is certified to have protections similar to those found in our box mods, such as short-circuit, overheating, and overcharge protections. These functions are already present in the VX4, which is why it can also be used with other 5V 2A adapters, preferably of good quality and with protections similar to those of the PD 20W.
The bottom features one of the few things that isn't optimized, namely the rubber feet, which don't raise the VX4 very much from the ground considering that the holes you see are designed to prevent overheating and keep the temperature under control. I also want to specify that there are no cooling fans. Currently, it's not a problem, but it could become one in summer, as depending on what you're charging, the VX4 may be required to run continuously for up to 24 hours. This can be solved by placing it on "cool" surfaces, from the floor to a marble countertop, or positioning it at an angle, with the two rubber feet at the back resting on a slightly elevated surface.
So who is it useful for? For example, for someone like me, who has been using 18650 batteries for 8 and a half years, and despite always buying Sony batteries, unfortunately, I've also had some fake ones. Despite precautions and charging at 500 mA, they've still worked. To see exactly how "damaged" they are simply by using them isn't easy, unless you estimate that with one cell, you might vape a little more or less than 1 ml of eliquid. With a bit of patience (and days), I've been able to estimate which ones to keep and which ones to throw away. The next batteries I purchase, I’ll be able to charge at 250 mA, extending their lifespan and getting better performance thanks to the VX4.
It could definitely be an upgrade for a vaper who already has a good charger in the 20-25 euro range and is possibly interested in getting another one as a backup. But by adding a few more dozen euros, they can opt for the VX4, making it the primary charger and upgrading. Given the issue of fake batteries, it could be the first tool to check if the mAh claimed by the manufacturer is real.
For more information, on the Xtar website, you can check out the official page of the Visible Mixer VX4 Charger (It is not an affiliate link):
XTAR Visible Mixer VX4 Charger - XTAR
I thank the community and the staff of e-cigarette-forum for the space, and Xtar for the gift of the VX4.
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