Uniross RB103244 1.2V Compatible Battery 1200mAh Ni-MH

Uniross RB103244 — 1.2V Ni-MH 1200mAh Replacement Battery

This is a 1.2V 1200mAh Ni-MH replacement cell for portable media players that use the Uniross RB103244 specification. It measures 66.78 × 16.70 × 5.96mm — a flat prismatic form factor common in slim MP3 and portable audio devices. Verify your original cell's markings match RB103244 before ordering.

• Ni-MH cell format: Portable media players in this class use a single low-voltage Ni-MH cell rather than a Li-ion pack because the audio circuit and firmware are tuned to a 1.0–1.4V discharge curve. Swapping chemistry breaks that voltage window and can cause false low-battery shutdowns or firmware lock-outs.
• Bench tested on actual hardware: We cycled this cell through charge and discharge on a media player platform. The cell accepted a full charge, held nominal voltage through the mid-cycle plateau, and the device recognised the battery without error flags.
• First-install charge protocol: Media players often enter deep discharge protection after extended shelf storage. Connect the charger immediately after installing this cell and leave it for at least 30 minutes before attempting to power on — the device needs a slow trickle to exit that protection state before it will accept a normal charge current.

Playback cutting out before the battery indicator shows empty

The audio amplifier in most portable media players draws a current spike when driving headphones at higher volumes. Near the end of a Ni-MH discharge cycle, internal cell resistance rises sharply, and that spike causes voltage to sag below the amplifier's operating threshold — even when the fuel gauge still shows charge remaining. This is not a faulty cell; it is a known characteristic of Ni-MH at end-of-discharge. Run a full charge cycle and avoid maximum volume levels during the final portion of the discharge to reduce drop-outs.

Battery percentage jumping erratically after fitting a new cell

Most media players estimate battery level by tracking voltage against a fixed discharge curve stored in firmware. A fresh Ni-MH cell has a slightly different resting voltage profile than a worn cell, so the indicator recalibrates over the first two or three full charge-discharge cycles. Readings will stabilise once the firmware has mapped the new cell's curve. Run the device down to automatic shutdown and then charge fully — repeat this two or three times and the percentage display should track accurately from approximately 1.25V down to the 1.0V cutoff.