303040 3.7V 300mAh LiPo Battery

Ultra-Slim by Design. Precision-Powered for Wearables.

The 303040 3.7V 300mAh Lithium Polymer Battery is the go-to ultra-slim power solution for modern smart watches, Bluetooth earphones, kids wearables, and compact IoT devices. At just 3mm thin and 5.5g lightweight, it delivers precisely calibrated 300mAh capacity with built-in PCM protection and Grade A consistency — everything a wearable designer needs in the smallest possible package.

✅ Key Features

🔋 300mAh Precision Capacity – Optimized for Wearable Endurance Precisely calibrated at 300mAh to match the power profile of smart watches, Bluetooth earphones, and compact wearable devices — supporting GPS tracking, Bluetooth connectivity, health monitoring sensors, and notification functions throughout a full day of use. The right capacity in the right size — no wasted space, no excess weight.

📐 3mm Ultra-Slim Profile – 303040 (3.0 × 30 × 40mm) At just 3mm thin and approximately 5.5g, the 303040 ranks among the slimmest soft-pack LiPo cells on the market. Purpose-built for wearable applications where every millimeter of thickness and every gram of weight directly impacts user comfort and product aesthetics — delivering maximum energy in minimum space.

🛡️ Built-in PCM 4-in-1 Protection – Safe & Reliable High-performance Protection Circuit Module (PCM) provides comprehensive four-layer defense against overcharge, over-discharge, overcurrent, and short circuit — ensuring safe, stable operation across all wearable usage scenarios including children’s devices, medical monitors, and professional IoT applications. Prevents overheating and swelling risk even in ultra-slim, space-constrained enclosures.

⚡ Stable 3.7V Output – Consistent Wearable Performance Advanced polymer electrolyte system maintains a flat, stable discharge curve with minimal voltage deviation throughout the full discharge cycle — ensuring GPS modules, Bluetooth chips, health sensors, and display screens in smart watches and wearable devices receive clean, consistent power from full charge to cutoff, preventing signal drops, audio interference, or unexpected shutdowns.

🏋️ Near-Weightless Comfort – Designed for All-Day Wear 3mm slim profile combined with ~5.5g ultra-light weight creates a virtually imperceptible wearing experience — whether on the wrist, in the ear, or embedded in clothing accessories. Reduces total device weight to support comfortable all-day and all-night continuous wear without fatigue or discomfort.

♻️ 500+ Cycle Life – Durable Wearable Power Rated for over 500 full charge/discharge cycles with ultra-low self-discharge rate. Retains excellent capacity after extended storage — extending smart watch and wearable device service life, reducing replacement costs, and supporting long-term brand loyalty among end users.

🏆 Grade A Cells – Precision ±10mAh Consistency Every micro cell undergoes rigorous multi-stage electrochemical performance testing with capacity variance tightly controlled within ±10mAh — applying a stricter consistency standard specifically designed for small-capacity cells where uniformity is most critical. Stable internal resistance across all batches ensures predictable, reliable performance at every scale of production.

🌍 CE Certified & Globally Compliant CE / UN38.3 / RoHS / MSDS / IEC62133 certified — fully compliant with EU market entry requirements and international air freight regulations. Complete documentation package available for seamless customs clearance across all major global markets.

📦 In Stock – Ready for Immediate Dispatch Strong warehouse inventory available for fast fulfillment. Flexible order quantities from prototype samples to mass production runs — with competitive lead times designed for the fast-moving wearable consumer electronics market.

📦 Specifications

🔌 Compatible Applications

🔍 Ultra-Slim Series Comparison

✅ The 303040 hits the sweet spot — 50% more capacity than the 302530 in the same 3mm slim profile, making it ideal for feature-rich smart watches requiring GPS, calling, and health monitoring simultaneously.

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