Fly W970 V973 V870 Replacement Battery 3.7V 1750mAh

Fly W970 / V973 / V870 — 3.7V Li-ion Replacement Battery (KLB175N267)

This is a 3.7V, 1750mAh Li-ion cell for the Fly W970, V973, V870, N970, and N970S smartphones. It replaces the original KLB175N267 battery when the existing cell has degraded and no longer holds a usable charge. Capacity is 6.48Wh — identical to the factory specification.

• W970 / V973 / V870 / N970 platform fit: These five models share the same 3.7V single-cell architecture, connector pinout, and BMS handshake protocol — that is why one cell covers the full group. The fuel gauge IC on each model reads the same charge termination signals from this replacement cell.
• Bench tested on actual hardware: We cycled this cell through charge and discharge on the W970 platform. The BMS accepted the cell without fault flags, charge termination triggered cleanly at 4.2V, and the protection circuit tripped correctly under a simulated short-load event.
• First-cycle fuel gauge reset: After fitting this cell, disable fast charging and run one complete discharge down to automatic shutdown, then charge to 100% uninterrupted. This gives the coulomb counter a full reference curve on the new cell before it begins tracking state-of-charge under normal use.

Sudden shutdown at 20–30% on the Fly W970 after a cell swap

This happens because the fuel gauge IC still holds the discharge curve of the old, degraded cell. The new cell has a steeper voltage cliff at the low end — the phone's modem or display draws a current spike, terminal voltage drops below the shutdown threshold, and the OS cuts power before the gauge reads zero. It is not a fault in the replacement cell. One full discharge-to-shutdown followed by an uninterrupted charge to 100% recalibrates the coulomb counter. After that cycle, shutdowns at false-low percentages stop.

Phone not powering on after the replacement battery sat in storage

Li-ion cells self-discharge during storage. If the cell dropped below approximately 2.5V, the BMS enters lockout to prevent damage from an over-discharged state. The phone will not respond to the power button and may show no charge indicator. Connect the phone to a wall charger — not a PC USB port — and leave it for 15–20 minutes without pressing anything. Most BMS circuits re-initialise once the charger pushes the cell back above the 2.5V threshold, after which the phone will boot and continue charging normally.