IBM2.4GIG Cordless Phone Replacement Battery 3.6V 1200mAh

IBM IBM2.4GIG — 3.6V Ni-MH Replacement Battery

This is a 3.6V, 1200mAh Ni-MH battery for the IBM IBM2.4GIG cordless phone handset. It restores wireless operation when the original pack no longer holds a charge. Voltage and cell chemistry match the original IBM specification exactly.

• IBM2.4GIG handset fit: The IBM2.4GIG uses a standard 3-cell Ni-MH pack in a compact form factor. This battery matches the connector orientation, physical footprint (50.43 x 42.54 x 14.40mm), and voltage rail that the handset's charging circuit expects. No modifications needed.
• Bench tested on actual hardware: We cycled this pack through charge and discharge on the IBM2.4GIG platform. The BMS accepted charge from the base station without error, and cell voltage climbed evenly across all three cells under normal handset load.
• First-charge protocol for Ni-MH handsets: After installing, seat the handset in the base for a full 16 hours before first use. Ni-MH cells ship in a partially discharged state and need a slow initial charge cycle to reach rated 1200mAh capacity. Skipping this shortens usable charge from the first day.

Base station showing no charge after installing a new Ni-MH pack

Ni-MH batteries lose voltage during storage. If the pack voltage drops low enough, the IBM2.4GIG base station's charge controller may not recognise it as a valid battery and will withhold charging current entirely. This is a threshold check in the base hardware, not a fault with the battery. Place the handset in the base and leave it undisturbed for at least an hour — the trickle current is usually enough to push cell voltage above the acceptance threshold and trigger a normal charge cycle. If the charge indicator still does not activate after two hours, remove and reseat the handset firmly to ensure pin contact.

Range drops noticeably mid-call after a battery swap

Reduced range after fitting a new Ni-MH pack usually means the cells haven't completed their conditioning cycles yet. Under RF transmit load, an unconditioned Ni-MH pack sags in voltage faster than a fully cycled one, and the handset's transmit power follows that sag down. The fix is straightforward: run three to five full charge-and-use cycles, allowing the handset to discharge through normal use before returning it to the base. By cycle four, cell voltage under load stabilises and range returns to normal operating distance.