LED
LCD
Product Description
The HD-0688 is a compact, high-efficiency single-slot universal smart charger engineered specifically for 3.7V Lithium-Ion cylindrical cells, with an optimized focus on standard 18650 batteries. Designed for safe and effortless benchtop utility, this plug-and-play charger features an intelligent automatic stop mechanism that cuts off power output once the cell reaches peak capacity ($4.2\text{V}$), protecting the battery against overcharging, capacity degradation, and thermal stress. Its rugged, spring-loaded slider mechanism adapts smoothly to varying cell lengths, maintaining stable electrical contact throughout the cycle. For hardware developers, field service technicians, and electronics hobbyists, it provides a highly reliable, standalone power maintenance accessory to keep diagnostic equipment and prototyping arrays continuously fueled.
Pinout / Layout Connections
The module features an integrated all-in-one chassis with direct electrical plug interfaces:
AC Input Power Plug: Built-in flip-out or fixed wall plug pins designed to fit directly into standard electrical outlets (AC 100V – 240V).
Single Independent Charging Slot:
Top Stationary Contact (+): The upper fixed metal plate serves as the positive terminal connection.
Bottom Spring Slider (-): The tensioned lower sliding contact plate accommodates various cell lengths and serves as the negative terminal connection.
Status LED Indicator: A clear, surface-mounted LED light that displays immediate visual status tracking:
Red Light: Active charging cycle in progress.
Green Light: Charging cycle complete (Auto-Stop engaged) or empty slot standby state.
Applications
Battery Maintenance: Recharging individual 3.7V 18650 Li-ion cells utilized in high-drain industrial testing gear.
Prototyping Setup Supporter: Keeping spare 18650 power cells ready for wireless IoT nodes, field microcontrollers, and portable robotic chassis.
Field Service Kit Asset: Providing a reliable charging solution for tactical LED flashlights, electronic test probes, and portable meters.
DIY Hardware Testing: Safe charging and validation of recovered or individual lithium-ion cells before assembly into battery brackets.
Technical Specifications
| Parameter | Value / Specification |
| Standard Part Number | HD-0688 |
| Input Voltage Range | AC 100 V to 240 V, 47/63 Hz |
| Output Charging Voltage | DC 4.2 V ($\pm 1\%$) |
| Charging Current Output | ~450 mA to 500 mA |
| Supported Chemistries | 3.7V Lithium-Ion (Li-ion) |
| Supported Battery Sizes | 18650 (Primary focus), 14500, 16340 |
| Protection Mechanism | Overcharge protection with automatic voltage termination (Auto-Stop) |
| Status Indicator | Dual-State LED (Red: Charging / Green: Full or Empty) |
