GP 14M Replacement Battery 1.2V 1200mAh Ni-MH

GP GP14M — 1.2V Ni-MH 1200mAh Replacement Battery (14M145)

This is a 1.2V, 1200mAh Ni-MH replacement cell for portable media players that use the GP 14M battery format. It covers part numbers 14M, GP14M, 14M145, and HF18/07/68. When the original cell degrades and can no longer hold charge, this cell restores full operating voltage without replacing the entire device.

• GP 14M cell format: Devices spec'd to this format share a common voltage rail at 1.2V nominal and a flat form factor — 66.78 x 16.70 x 5.96mm — that fits the battery bay without modification. The Ni-MH chemistry matches the charge curve the original charging circuit expects.
• Bench tested on actual hardware: We cycled this cell through charge and discharge on a controlled bench rig. The BMS handshake completed normally, charge acceptance was consistent across cycles, and cell temperature stayed within Ni-MH operating limits throughout.
• First-charge protocol for media players: If the player has been stored with a flat cell, connect it to the charger and leave it for 30 minutes before attempting to power on. Media players using this cell format often enter a deep discharge protection state that requires a slow trickle to pre-charge the cell before the device accepts normal current.

Playback cutting out before the battery indicator shows empty

Ni-MH cells discharge along a relatively flat voltage curve, then drop sharply near end of charge. The audio amplifier inside most portable media players draws a small current surge when driving headphone output. At the tail end of discharge, that surge is enough to pull cell voltage below the device's cutoff threshold — even when the battery gauge still reads partial charge. This is a voltage sag issue, not a capacity issue. A fresh, fully charged cell eliminates the sag margin problem; charge to full and the symptom stops.

Battery percentage jumping erratically after cell replacement

Portable media players track charge state by measuring cell voltage against stored thresholds calibrated to the original cell's discharge curve. A new Ni-MH cell, especially before its first full cycle, sits at a slightly different resting voltage than the old degraded cell. The indicator algorithm reads that as an inconsistency and recalibrates in steps, causing visible jumps. Run two full charge-to-discharge cycles and the gauge stabilises. After the second cycle, resting voltage should read between 1.20V and 1.25V at partial charge.