The BN51 is a Li-ion Polymer (Li-Po) rechargeable smartphone battery designed as the original or replacement battery for certain Xiaomi/Redmi handsets
Specifications
Model: BN51 (battery part number / model code)
🔋 Battery Type: Lithium-ion Polymer (Li-Po) rechargeable cell — combines light weight with good energy density.
🔋 Capacity:
• Rated: ~5000 mAh (typical)
• ~19.2 Wh energy capacity (approx.)
⚡ Nominal Voltage: 3.85 V — standard for many smartphone Li-Po batteries.
🔌 Charging Voltage: ~4.40 V maximum standard charging voltage.
📏 Physical:
• Slim, lightweight design made for internal installation in supported Xiaomi phones.
• Black casing typical for smartphone batteries.
🧠 Safety & Certifications (varies by seller):
• Many replacement BN51 batteries include CE, UL, FCC, RoHS safety certifications for compliance with international standards.