Charger for cylindrical Li-ion and NiMH batteries Xtar VC4

Xtar is a renowned manufacturer of high-quality chargers for Li-ion batteries, flashlights, and Li-ion batteries. Xtar products are sold in over 120 countries, including the USA, Germany, Japan, and Russia. For the production of Xtar chargers, the highest quality materials are used - from the casing material to efficient electronics. All Xtar chargers have CE certification required in European markets.

VC4 is a professional microprocessor charger with a three-stage charging process TC/CC/CV and an LCD display. It charges 1-4 Li-ion cells 3.6 / 3.7V and Ni-MH of any capacity in sizes AAA/R03, AA/R6, 10440, 14500, 14650, 16340, 17500, 17670, 18350, 18500, 18650, 18700. In the two outer channels, it is possible to charge batteries in sizes R14, R20, 20700, 21700 - only unprotected, 22650, 25500, 26650, 32650.

The backlit LCD display of the Xtar VC4 charger continuously shows information about the charger’s operating status: the voltage of the charged batteries, the charging current, the charge used to charge the cells, indicates any errors, and informs about the completion of charging. At the same time, the current operating status for two channels is displayed. Switching between the other two channels is possible using the CH button on the charger’s casing. The information about the used charge can be used to measure the capacity of the batteries. To measure the capacity of a battery, it should be discharged to its appropriate cutoff voltage level (usually 2.5V for Li-ion, 0.9V for Ni-MH) and placed in the VC4 charger. After charging is complete, the value of the charge used to charge the battery can be read from the display. This will always be a value 3-5% higher than the actual capacity of the battery. This is due to the fact that the battery charging process is never 100% efficient, meaning that a slightly larger charge is needed to charge the battery than what results from the actual capacity of the cell.

The maximum charging current is 1A and is available only for the two outer channels and only when the middle channels are not in use. Batteries in the middle channels are always charged at a current of 0.5A. When charging 3 or 4 batteries, the VC4 charges all batteries at a current of 0.5A.

What is the TC/CC/CV charging method? It is a three-stage charging process for Li-ion cells that ensures the cell is kept in good condition by charging at the appropriate current at each stage and completing the charging process at the right moment.
The individual stages of the TC/CC/CV process are:

• TC Phase: cells discharged below 2.9V are 'woken up' with a lower current.
• CC Phase: after reaching 2.9V, the cell is charged with a constant current of between 0.1A and 1A (depending on the power source used and the number of batteries being charged).
• CV Phase: when the cell is almost fully charged, the charger switches to charging with a decreasing current until the voltage of 4.2V is reached on the cell. After reaching 4.2V, the charging process is complete - the battery is fully charged.

Batteries left in the charger will undergo a natural self-discharge process. Charging of Li-ion batteries will resume when the voltage on the battery drops below 3.9V. For Ni-MH batteries, charging is not resumed when the voltage drop is due to self-discharge.

The Xtar VC4 charger has a function for reactivating deeply discharged cells and cells with a voltage of 0V. Many chargers on the market are unable to charge such batteries. Here, the Xtar VC4 charger comes to the rescue, which in many cases allows for the 'rescue' of such cells. Simply place the deeply discharged battery into the VC4 charger, just like with normal charging - the charger will detect the discharged cell and attempt to reactivate it. Note! Cells discharged below a certain level may suffer irreversible damage, and their reactivation may be impossible. It is advisable to avoid overly deep discharging of Li-ion and Ni-MH batteries - this can lead to a significant reduction in their lifespan and capacity or render them completely inoperative.

Included with the Xtar VC4 charger is a USB cable. The power adapter is not included in the set. To power the charger, any charger with a USB cable, e.g., from a phone, or a USB socket or a computer with a free USB port will suffice. The recommended power of the USB adapter is 2.1A (2100mA). It is possible to use a weaker adapter; the VC4 will adjust the charging current to the capabilities of the power source.