The 3.7V Lithium Battery Protection Board is a compact, essential safety module designed to protect single-cell lithium-ion and lithium-polymer batteries from overcharge, over-discharge, and overcurrent conditions. It is compatible with 18650 cells, polymer pouch cells, and other 3.7V lithium batteries, making it an indispensable component for DIY battery packs, power banks, and portable electronics.
At the heart of the board is a protection circuit that continuously monitors the battery voltage and current, disconnecting the load or charger if any parameter exceeds safe limits. This protects both the battery and your connected devices from damage, extending battery lifespan and ensuring safe operation.
The board provides three critical protection functions:
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Overcharge protection — Disconnects the charger when the battery voltage reaches approximately 4.25V to 4.3V, preventing damage from excessive charging.
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Over-discharge protection — Disconnects the load when the battery voltage drops to approximately 2.5V to 3.0V, preventing deep discharge that can permanently damage the battery.
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Overcurrent protection — Disconnects the output when current exceeds approximately 3A, protecting against short circuits and excessive loads.
The board features a solder pad design that supports both direct soldering and spot welding. The exposed pads allow you to solder wires directly to the board, while also being compatible with spot-welded nickel strips for professional battery pack assembly. This dual-method approach gives you flexibility in how you integrate the board into your project.
The multi-parallel ready design allows you to connect multiple protection boards in parallel for higher current capacity, or to protect multiple cells in a parallel configuration. This makes the board suitable for a wide range of battery pack designs, from small single-cell projects to larger multi-cell packs.
The compact PCB design is sized to fit neatly alongside 18650 cells and polymer batteries, making it ideal for space-constrained applications. The board includes B+ and B- pads for battery connection, and P+ and P- pads for the protected output.
The 3.7V Lithium Battery Protection Board is widely used in DIY power banks, 18650 battery packs, portable speakers, flashlights, vaping devices, RC vehicles, solar garden lights, and any application where lithium battery safety is critical.
Important Note: This protection board is designed for single-cell (1S) 3.7V lithium batteries. For multi-cell packs, each cell should have its own protection board, or a multi-cell BMS should be used. Always verify the voltage and current ratings match your application before installation.
Whether you are building a custom power bank, assembling an 18650 battery pack, or adding safety protection to a portable device, the 3.7V Lithium Battery Protection Board provides a reliable, cost-effective solution. It is suitable for individual makers, students, and businesses purchasing in bulk for product development or educational programs.
Features
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Comprehensive protection — Overcharge, over-discharge, and overcurrent protection
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3A overcurrent protection — Disconnects output when current exceeds safe limits
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Solder pad design — Supports both direct soldering and spot welding
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Multi-parallel ready — Connect multiple boards for higher current capacity
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Wide compatibility — Works with 18650 and polymer lithium cells
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Compact PCB design — Sized for space-constrained battery packs
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Simple connection — B+/B- for battery, P+/P- for protected output
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Wide application range — Power banks, battery packs, portable devices, DIY projects
Technical Specifications
| # | Parameter | Specification |
|---|---|---|
| 1 | Compatible Battery | 1S 3.7V lithium-ion / lithium-polymer |
| 2 | Overcharge Protection Voltage | ~4.25V – 4.3V |
| 3 | Over-discharge Protection Voltage | ~2.5V – 3.0V |
| 4 | Overcurrent Protection | 3A (typical) |
| 5 | Continuous Discharge Current | Variant dependent (typically 2A–3A) |
| 6 | Connection Type | Solder pads (spot welding supported) |
| 7 | Multi-Parallel | Supported |
| 8 | Module Dimensions | Compact PCB for 18650/polymer cells |
