The BN4A is a rechargeable lithium-ion polymer (Li-Po) internal smartphone battery designed to provide stable power and long usage for compatible Xiaomi/Redmi devices.
Specifications
Model Name: BN4A
Battery Type: Rechargeable Lithium-ion Polymer (Li-Po) — slim, lightweight, and high energy density chemistry.
Nominal Capacity: 3900 mAh typical, up to 4000 mAh on some original batteries.
Energy: Approximately 15.0 – 15.4 Wh.
Voltage:
• Nominal Voltage: 3.85 V — standard for modern smartphone Li-Po cells.
• Charge Limit Voltage: ~4.40 V (max safe charge).
Chemistry: Lithium-ion Polymer (Li-Po).
Color: Usually black (typical for replacement batteries).
Protection & Safety:
• Built-in protection circuitry (over-charge, over-discharge, short-circuit protection) on many versions.
• Common certifications include CE, RoHS, FCC, CCC, UL (varies by seller).
Charging Time: ~2–3 hours (depends on charger and phone).
Cycle Life: Often rated for >550–600+ charge cycles before significant capacity loss (varies by manufacturer).
Approx. Weight: ~55–70 g (varies by manufacturer).
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📱 Compatibility
Designed as a direct replacement battery for these Xiaomi/Redmi models (matching the BN4A part number):
• Xiaomi Redmi Note 7
• Xiaomi Redmi Note 7 Pro
• Xiaomi Redmi Note 7S (depending on specific variant)
