VIDEX Li-Ion Battery Chargers (18650/21700)

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Li-Ion chargers (18650, 21700)

High-capacity lithium-ion (Li-Ion) batteries, such as the legendary 18650 or the powerful 21700 and 26650 formats, are the "lifeblood" of modern powerful electronics. They are used in expensive power tools, measuring devices, e-cigarettes, and custom-built (DIY) power packs. Lithium chemistry is extremely temperamental and dangerous if charged incorrectly – it demands surgical charging precision and respect. VIDEX specialized Li-Ion chargers are designed exactly for the safe and fast servicing of these demanding industrial cells.

Why lithium cells require only a professional VIDEX charger:

Outstanding precision (CC/CV algorithm): Unlike cheap chargers, charging happens in two stages – first with Constant Current, and then slowly with Constant Voltage. This ensures a 100% full charge without ever exceeding the critical 4.2V limit for lithium, which fully protects the cell from degradation, capacity loss, or swelling risk.
Fast charging for high-capacity cells: If you have a modern 5000 mAh 26650 or 21700 battery, a weak 0.5A charger will take 24 hours. VIDEX models offer enough power (up to 2A per channel) to quickly get you back to your work or project.
Physical compatibility with large sizes: The charger's metal sliders are specially adapted for long and thick industrial cells, ensuring stable contact and that the battery won't jump out of the track during charging.

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Q: What is the exact CC/CV (Constant Current / Constant Voltage) charge curve in 18650 and 21700 Li-Ion chargers?

A: In phase 1 (CC), the charger supplies a fixed direct current (0.5A, 1A, or 2A) until the cell reaches 4.20V, and in phase 2 (CV), the voltage is held at 4.20V while the current drops in steps. Charging is completely terminated once the current drops below 50 mA. This two-stage method prevents overheating of 3.7V lithium-ion cells and guarantees a maximum number of cycles.

Q: Why is it necessary to use chargers with an extended sliding contact and 2A current for charging large-size 21700 and 26650 Li-Ion batteries?

A: High-capacity (4000–5500 mAh) batteries require a larger charging current (1A–2A) so that the charging time does not exceed 3–4 hours. The mechanical terminals of VIDEX Li-Ion chargers provide up to 75 mm of travel, safely securing 21700 cells featuring a built-in protection board (PCB).

Q: Why is it critically important for Li-Ion chargers to provide a precise 4.20V (±0.05V) charge voltage cut-off?

A: Lithium-ion electrochemistry is extremely sensitive to overvoltage; exceeding 4.30V triggers electrolyte decomposition and gas evolution within the cell. A precise 4.20V cut-off threshold guarantees the cell's structural stability and prevents thermal auto-ignition risks.

Q: How does the 0V recovery function work in Li-Ion chargers when the battery's BMS protection has triggered?

A: When the voltage of a protected Li-Ion battery drops below 2.5V due to deep discharge, its internal PCB microchip disconnects the external contacts. The charger supplies a special micro-pulse voltage that unlocks the protection board and safely initiates the battery charging cycle from a zero state.

Q: What is the working life and safety parameters of Li-Ion battery chargers under continuous load?

A: Industrially tested electronic components ensure continuous operation of the chargers for more than 5 years. The chargers are equipped with protection against short circuits, overcharging, and overheating, complying with CE and RoHS safety directive requirements.