# Power supply 220VAC, connector 5.5x2.5mm, at 8.4V, lithium 2S charging, 1A

> Charger for Li-Ion 18650 batteries in 2S configuration, with AC 100-240V input and DC 8.4V 1A output. Connector 5.5x2.5mm, polarity inner positive, outer negative. Intended for correctly charging compatible 2S lithium battery packs.

- Page: https://sigmanortec.ro/en/power-supply-220vac-connector-55x25mm-at-84v-lithium-2s-charging-1a
- Price: 40.81 RON
- Availability: In stock; 1-2 zile
- Reference: 7754022 · EAN: 5946261407279
- Category: Electronic components > Battery > Battery Chargers
- Specifications: Technology: Lithium Ion; Load voltage: 8.4VDC; Number of cells: 2S; Maximum Output Current: 1 A; Input Voltage: 220VAC; Input Voltage Type: AC; Output Voltage Type: “DC” in Romanian can mean **“de ce”**, which translates to **“why”** in English.; Power connector: 5.5x2.5 mm
- Package (shipping data): 0.098 kg
- Updated: 2026-10-16
- Shop: [Sigmanortec.ro](https://sigmanortec.ro/en/llms.txt)
- Prices: RON, VAT included; prices and stock as of 2026-10-22 05:45 (Europe/Bucharest)

## Description

Charger adapter for Li-Ion 18650 batteries in 2S configuration, provides a stable 8.4V 1A output for proper power supply and charging. It accepts universal input 100-240VAC, has a 5.5x2.5mm plug with center positive, outer negative polarity, suitable for 2S packs and compatible charging circuits.
The 8.4V 1A power and charging adapter is a high-quality adapter, designed for the correct and safe charging of 18650 Li-Ion batteries connected in a 2S configuration. It provides constant current power, suitable for charging lithium batteries, and is a reliable choice compared to generic adapters, for long-term use.
The main features are the build quality, the universal 100-240VAC input voltage at 50/60Hz, the 8.4VDC output at 1A, corresponding to the maximum charging voltage of a 2S Li-Ion pack, constant-current charging, and the 5.5x2.5mm male plug, with positive center and negative outer polarity.
The adapter is suitable for 2S packs made from 18650 batteries used in robotics kits and Arduino- or ESP32-based cars, in flashlights, portable speakers, and other DIY projects powered at 7.4V nominal.
Warning!
This adapter operates at 220VAC mains voltage, which can cause serious electric shock or death if handled incorrectly or used by unqualified personnel. Do not open the housing and do not use the adapter if the cable or housing is damaged.
Incorrect charging of Li-Ion batteries can cause fire. Do not charge damaged, swollen, or excessively heating batteries, and do not leave charging unattended.
Specifications:
Input voltage: 100-240VAC
Input frequency: 50/60Hz
Output voltage: 8.4VDC
Output current: 1A
Maximum power: 8.4W
Compatible battery type: Li-Ion
Battery configuration: 2S
Connector: 5.5x2.5mm male
Polarity: Positive center, negative outer
Usage:
Check that the pack consists of 2 Li-Ion cells connected in series (2S), with a maximum charging voltage of 8.4V.
Use the pack together with a 2S BMS protection module, preferably with balancing, so that the cells charge evenly and are protected against overcharging.
Check that the pack or charging circuit has a 5.5x2.5mm female connector with positive center polarity. A 5.5x2.5mm plug does not make secure contact in a 5.5x2.1mm female connector, such as the one on the Arduino Uno.
Plug the adapter into the 220VAC outlet, then connect the plug to the battery pack or charging circuit.
Monitor the charging. The duration depends on the pack capacity; for example, a 2000mAh pack charges in approximately 2.5 - 3 hours.
After charging is complete, first unplug the adapter from the outlet and then disconnect the plug from the battery pack.
Do not use the adapter for other types of batteries, such as NiMH, LiFePO4, or lead-acid, or for equipment with different voltage and polarity requirements.
Use the adapter only in dry, well-ventilated areas, away from heat sources.