Sagem DECT Phone 330 Replacement Battery T306 3.6V 400mAh

Sagem DECT Phone 330 — 3.6V Ni-MH Replacement Battery (T306)

This is a 3.6V, 400mAh Ni-MH replacement battery for the Sagem DECT Phone 330 cordless handset. It also fits the DCP 12-300, DCP 40-330 ISDN, and DCP300 series handsets. It matches the original T306 specification and fits the same battery compartment without modification.

• DECT 330 series compatibility: These handsets share the same 3.6V single-cell Ni-MH architecture and T306 form factor. The battery connector, cell count, and compartment dimensions are identical across the DCP 12-300, DCP 40-330 ISDN, and DCP300 variants.
• Bench tested on actual hardware: We cycled this pack on a DECT handset base station and confirmed the BMS accepted the charge without error. Voltage stabilised at 4.2V at full charge and the handset registered a full battery indicator after a slow overnight charge.
• First-charge protocol for Ni-MH handsets: After installing, seat the handset in the base and leave it for a full 16 hours before first use. Ni-MH cells in cordless phones ship partially discharged and need a slow initial charge cycle to reach rated capacity — skipping this step can permanently reduce how much charge the pack holds.

Talk time shorter than expected after fitting a new T306 pack

Ni-MH cells do not deliver full rated capacity on the first charge cycle. The DECT Phone 330 charges at a low trickle rate, which means the first few cycles will feel short compared to the original battery at its best. Capacity builds across three to five full charge-discharge cycles. Run the handset until the low battery tone sounds, then return it to the base for a full 16-hour charge — repeat this three times and rated capacity will stabilise.

Base station showing no charge or error light after battery swap

Replacement Ni-MH packs often sit in storage for months and arrive at a resting voltage below 3.0V. Some DECT base stations interpret this as a fault and refuse to initiate a charge cycle. If the charge indicator stays off or shows an error, remove the handset, wait 30 seconds, and reseat it firmly — this resets the base station's charge controller. If the error persists, check that the handset contacts and base cradle contacts are clean and making solid contact.