3.7V 50mAh Lithium Polymer Battery AS401119
Ultra-compact 3.7V 50mAh lithium polymer battery (AS401119) with integrated Seiko S-8261 protection circuit and 10K NTC thermistor. Weighs just 1.8g at 4.0mm thin with 3-wire bare leads (UL3302 32AWG) — ideal for TWS earbuds, hearing aids, and mini IoT devices. OEM/ODM customization available.
Description
Model AS401119 – 3.7V 50mAh Lithium-ion Polymer Battery (1S LiPo)
Voltage: 3.7V | Capacity: 50mAh (0.185Wh) | Size: 22 x 11.8 x 4.0mm (with PCM) | Weight: 1.8g
The AS401119 is an ultra-compact 3.7V 50mAh lithium polymer battery engineered for the smallest portable electronics where every millimeter and gram matters. Weighing just 1.8g and measuring only 4.0mm thin (with protection circuit), this tiny 1S LiPo battery delivers 0.185Wh of reliable power in a miniature form factor.
Equipped with an integrated Seiko S-8261-G3J protection IC, dual 8205A MOSFETs, and a 10K NTC thermistor, the AS401119 provides comprehensive protection against over-charge, over-discharge, over-current, and short circuits — with real-time temperature monitoring for precision applications. The 3-wire bare lead configuration (Red / White NTC / Black, UL3302 32AWG) offers maximum design flexibility without a pre-installed connector. Whether you are designing TWS earbuds, hearing aids, or mini IoT sensors, this small rechargeable lipo battery delivers consistent 3.7V performance in the tightest enclosures.
Technical Specifications
| Battery Type | Lithium-ion Polymer Battery (1S LiPo) |
| Part Number | AS401119 (P/N: AS-401119-0050-112) |
| Voltage @ Capacity | 3.7V @ 50mAh (0.185Wh) |
| Protection Circuit | Yes (PCM Included) Seiko S-8261-G3J IC + 8205A MOSFET + 10K NTC (Murata) |
| Cell Dimensions (L x W x T) | 19.5mm x 11.5mm x 3.8mm |
| Pack Dimensions (with PCM) | 22.0mm x 11.8mm x 4.0mm |
| Weight | Approx 1.8g |
| Wire & Leads | 3-Wire Bare Leads (No Connector) UL3302 32AWG | Red(+): 4±2mm, White(NTC): 8±2mm, Black(-): 12±2mm |
| Charge Current | 0.2C (10mA) Standard | Max 1.0C (50mA) |
| Charge Voltage | 4.20V |
| Max Discharge Current | 50mA (1.0C Continuous) |
| Discharge Cut-off Voltage | 3.00V |
| AC Impedance | ≤480mΩ |
| Cycle Life | ≥80% after 300 cycles | ≥65% after 500 cycles |
| Energy Density | 230 Wh/L |
| Operating Temperature | Charge: +10°C ~ +45°C | Discharge: +10°C ~ +50°C |
| Storage Temperature | +15°C to +35°C (Recommended: 20°C at shipment state) |
| Shipping Voltage | >3.80V (70~80% charged) |
| Certifications | UL1642, CE, IEC62133, UN38.3, RoHS, REACH, Halogen Free |
Protection Circuit Module (PCM) Parameters
| Over-Charge Protection Voltage | 4.28 ± 0.025V |
| Over-Discharge Protection Voltage | 3.00 ± 0.005V |
| Over-Current Protection | 1.00 ~ 1.50A |
| Normal Operation Current Consumption | ≤7µA |
Core Advantages
- ✔
Ultra-Compact Form Factor: At just 4.0mm thin and 1.8g, this 50mAh tiny lipo battery fits into the tightest device enclosures — ideal for mini wearables and TWS earbuds where space is at a premium. - ✔
Premium Seiko Protection IC: Built-in Seiko S-8261-G3J protection IC with dual 8205A MOSFETs safeguards the cell against over-voltage, over-current, over-discharge, and short circuits — ensuring long cycle life and safe operation. - ✔
3-Wire NTC Temperature Monitoring: Red/Black power leads plus a dedicated White NTC (10K Murata) wire enable precision temperature sensing — essential for medical devices, wearables, and high-reliability applications. - ✔
High-Quality Silicone Wires: Features UL3302 32AWG flexible silicone wires — heat-resistant, ultra-thin, and easy to route in compact internal layouts. Bare lead design (no connector) for maximum customization. - ✔
Proven Cycle Life & Certifications: Delivers ≥80% capacity after 300 cycles and is certified to UL1642, CE, IEC62133, UN38.3 — with RoHS, REACH, and Halogen-Free compliance for global market access.
Perfect For Applications
true wireless earbuds, Bluetooth headsets, hearing aids.
GPS pet trackers, smart watches.
BLE beacons, wireless sensors, remote controls.
portable monitors, wearable health trackers, medical sensors.
electric toothbrush heads, facial cleansing devices, beauty tools.
Customization Services (OEM/ODM)
We understand that every product is unique. Our services allow you to tailor the AS401119 to your specific needs:
- Connector Customization: Add JST, Molex, Hirose, or custom connectors to the bare wire leads — or keep them solder-ready for direct assembly.
- Wire Length & Gauge: Adjust wire length (currently 4~12mm) or switch to a different AWG gauge to fit your assembly.
- NTC Configuration: Add or remove the 10K NTC thermistor wire based on your application requirements.
- Battery Shape & Size: Modify dimensions or combine cells for higher voltage (2S/3S) or capacity (parallel configuration).
- Branding: Add your logo or specific labeling to the shrink wrap.
