Telekom Sinus 11 Replacement Battery 6V 1300mAh Ni-MH

Telekom Sinus 11 — 6V Ni-MH Replacement Battery

This 6V 1300mAh Ni-MH pack replaces the original handset battery in the Telekom Sinus 11 cordless DECT phone. It restores talk time and standby capacity lost to cycle degradation. Dimensions are 71.38 x 49.16 x 14.51mm — confirm these match your battery compartment before ordering.

• Sinus 11 handset fit: The Sinus 11 uses a 6V NiMH cell pack at this exact form factor. The voltage rail and connector position must match the original — this pack meets both requirements for that handset.
• Bench tested on actual hardware: We cycled this pack through charge and discharge on a NiMH-compatible analyser. The BMS held charge acceptance across multiple cycles with no thermal anomalies at full charge termination.
• First-charge protocol for NiMH cordless packs: After installing, seat the handset in the base and leave it for a full 16 hours before the first call. NiMH cells at storage charge need a slow initial cycle to reach rated capacity — skipping this step cuts usable talk time noticeably on early cycles.

Talk time shorter than original battery after replacement

NiMH cells ship in a partial storage charge, not a conditioned state. On the first two or three cycles, available capacity sits well below the rated 1300mAh. Each full charge-and-discharge cycle raises the usable ceiling until the cells stabilise — typically by cycle four or five. Do not judge this pack on cycle one; run it through at least five full cycles before comparing talk time against your original battery.

Base station showing no charge or error light after swap

The Sinus 11 base charges by detecting a minimum voltage threshold on the handset contacts. A NiMH pack that has sat in storage can drop low enough that the base reads it as absent or faulty rather than discharged. If the charge indicator stays off or shows an error, remove the handset, wait 30 seconds, and reseat it firmly so the charge contacts align. If the base still does not respond, check the pack voltage with a multimeter — a reading below 4.8V indicates deep discharge, and you may need to trickle-charge the pack externally at 100mA for 30 minutes to bring it above the base acceptance threshold.