Stabo ST940 ST955 Replacement Battery 4.8V 1500mAh

Stabo ST940 ST955 — 4.8V Ni-MH Replacement Battery

This is a 4.8V 1500mAh Ni-MH rechargeable battery for the Stabo ST940 and ST955 cordless DECT phone handsets. It replaces the original pack when the handset no longer holds a charge or loses talk time. Voltage, connector, and cell count match the original Stabo specification.

• ST940 and ST955 handset fit: Both models run the same 4.8V four-cell NiMH pack with an identical connector and footprint. The base station charges at the same rate for both handsets, so the same pack works across the two.
• Bench tested on actual hardware: We cycled this pack through charge and discharge on NiMH-compatible equipment. The BMS accepted charge without interruption, and cell balance held across all four cells through repeated cycles.
• First charge on a DECT handset: After installing, place the handset in the base for a full 16 hours before first use. NiMH cells in cordless phones need a slow initial charge to reach rated capacity — a short top-up charge will not fully condition the pack.

Base station showing no charge light on a new NiMH pack

NiMH batteries lose voltage during storage. If the pack sits long enough, its resting voltage can drop below the threshold the base station uses to detect a valid battery. The base then refuses to begin the charge cycle, and the charge indicator stays off. Most Stabo bases will recover the pack if you leave the handset seated for 30 to 60 minutes — the base trickle-feeds current until voltage rises above the acceptance threshold, then switches to normal charge mode. If the indicator still does not activate after an hour, check that the handset contacts are clean and fully seated in the cradle.

Handset loses range after a new battery is installed

DECT handsets regulate transmit power from the battery rail. When a freshly installed NiMH pack has not been fully conditioned, its voltage sags under the RF load during a call, and the handset steps down transmit power to compensate. This shows up as reduced range or a weak signal that was not there with the original battery. Run three to five full charge-and-discharge cycles through normal use and the cells will reach rated capacity. After conditioning, the voltage under RF load stabilises and range returns to normal.