SPIDER Automation | HX-2S-A2 Circular 2S 8.4V 5A 18650 Li-ion BMS Protection Board
The SPIDER Automation HX-2S-A2 Circular 2S Lithium-Ion Battery Protection Board is designed to provide essential electrical protection for compact two-cell series-connected rechargeable battery packs. It monitors battery-cell conditions and controls the protected charging and discharging paths to help reduce the risk of battery damage caused by abnormal operating conditions.
Featuring a circular PCB layout and a shared charge/discharge port arrangement, this module is intended for compatible battery assemblies where a compact protection circuit is required. Its intermediate battery connection allows the board to monitor the individual cells in a series arrangement.
Technical Features & Protection Functions
- Overcharge Protection: Monitors cell voltage and helps disconnect the charging path when an individual cell reaches its overcharge protection threshold.
- Over-Discharge Protection: Helps prevent excessive discharge by disconnecting the protected circuit when a cell reaches its lower voltage threshold.
- Overload Protection: Provides a protective response to excessive current drawn by the connected load.
- Short-Circuit Protection: Helps interrupt the protected output during a short-circuit condition.
- Cell Voltage Monitoring: The intermediate battery connection supports monitoring of the individual cells in the series arrangement.
- Shared Port Architecture: Common protected terminals are used for charging and discharging.
- Low Standby Consumption: Designed for low quiescent current during standby operation.
Electrical Connections & Terminal Functions
The HX-2S-A2 uses three battery-side connection points and a shared protected output connection. Correct cell order and polarity are essential. For a typical 2S series pack, B− connects to the pack negative, MB to the junction between the two cells, and B+ to the pack positive.
| Terminal | Connection Function |
|---|---|
| B+ | Connect to the positive terminal of the complete series battery pack. |
| MB | Connect to the midpoint junction between the two series-connected cells. |
| B− | Connect to the negative terminal of the complete series battery pack. |
| P+ | Shared positive connection for the external charger and load. |
| P− | Shared protected negative connection for the external charger and load. |
Circular PCB Design & Integration
The circular board format is intended for compact battery-pack arrangements where the available mounting area or enclosure geometry favours a round PCB. The shared charging and discharging terminals simplify external wiring by using one protected port for both functions.
- Round PCB format for compatible compact battery assemblies.
- Dedicated cell-positive, cell-negative and cell-midpoint connections.
- Common protected terminals for charging and load connections.
- Suitable for integration into custom electronic enclosures designed around the board geometry.
Applications
This protection board is intended for compatible 2S lithium-ion battery assemblies used in compact electronic projects. Application suitability depends on load current, battery type, wiring arrangement and physical compatibility of the circular PCB.
- Custom 2S 18650 Battery Packs: Protection circuitry for two-cell series-connected battery assemblies.
- Portable Electronic Projects: Battery protection for compatible rechargeable electronic devices.
- DIY Battery-Powered Equipment: Integration into custom equipment using a 2S Li-ion battery pack.
- Compact LED Projects: Protection for compatible battery-powered lighting circuits.
- Embedded Electronics: Battery protection for suitable embedded hardware projects.
- Wireless Devices: Integration into compatible wireless electronic equipment.
- IoT Prototypes: Protection for custom rechargeable power systems used in IoT prototypes.
- Portable Instrumentation: Battery protection for suitable portable measurement devices.
- DIY Robotics: Use in compatible low-current robotic electronics and control systems.
- Custom Enclosure Projects: Battery management integration where a circular PCB layout is suitable.
Package Contents
- 1 × HX-2S-A2 Circular 2S 8.4V 18650 Lithium-Ion Battery Protection Board
Product Specifications
| Parameter | Specification |
|---|---|
| Product Type | Lithium-Ion Battery Protection Board / BMS |
| Model | HX-2S-A2 |
| Battery Configuration | 2S – Two Cells in Series |
| Compatible Battery Chemistry | Conventional 3.7V Nominal Lithium-Ion |
| Nominal Pack Voltage | 7.4V |
| Full-Charge Pack Voltage | 8.4V |
| Recommended Charging Voltage | 8.4V CC/CV |
| Maximum Operating Current | 5A |
| Quiescent Current | Less than 10µA |
| Internal Resistance | Less than 300mΩ |
| PCB Shape | Circular |
| PCB Diameter | 18mm |
| PCB Thickness | 3mm |
| Battery Terminals | B+, MB, B− |
| Protected Port | P+, P− (Shared Charge/Discharge) |
Connection & Operating Recommendations
- Use Compatible Cells: Use two matched conventional lithium-ion cells with compatible chemistry, capacity, condition and state of charge. This board is not suitable for LiFePO4 cells.
- Connect the Cell Midpoint Correctly: The MB terminal must connect to the junction between the two series-connected cells. Incorrect midpoint wiring can damage the BMS or battery pack.
- Observe Polarity: Verify B+, MB and B− connections before connecting the battery pack.
- Use the Protected Port: Connect the charger and external load to P+ and P− according to the shared-port arrangement.
- Use a Dedicated Charger: Select a regulated 2S lithium-ion CC/CV charger. The protection board is not a standalone charger or voltage regulator.
- Check Load Compatibility: Confirm that the connected equipment’s starting current and normal operating current are suitable for the board.
- Monitor Battery Temperature: Stop operation if a cell becomes unusually hot, swells or shows signs of damage. Investigate the cause before reuse.
- Insulate Exposed Connections: Prevent accidental contact between conductive terminals and the battery enclosure or other metal parts.
