About this replacement
NEC DT330 / UX5000 DG-12e — 3.7V Li-ion Replacement Battery (A50-012628-001)
This is a 3.7V, 1100mAh Li-ion replacement battery for the NEC DT330 cordless DECT handset and compatible models including the DTL-12BT-1 and UX5000 DG-12e. It replaces OEM part number A50-012628-001 directly. The battery slots into the handset's rear compartment and connects through the standard NEC three-pin contact plate.
- DT330 / DTL-12BT-1 / UX5000 DG-12e compatibility: These models share the same physical form factor, contact orientation, and 3.7V Li-ion power rail. The BMS handshake is consistent across the group, so one battery covers the entire platform without modification.
- Bench tested on actual hardware: We cycled this battery through charge and discharge on the DT330 platform. The BMS held cutoff correctly at low-voltage threshold and accepted charge from the NEC base cradle without triggering fault states.
- First-charge protocol for Li-ion cordless handsets: Place the handset in the base immediately after installing this battery and let it charge uninterrupted until the charge indicator clears. Li-ion cells shipped at storage charge — the first full cycle from the base station brings the cell to rated capacity.
Talk time shorter than expected after fitting a new battery
A new Li-ion cell ships at around 40–50% state of charge to meet transport safety requirements. If you start using the handset before completing a full charge cycle, the available capacity is lower than rated. The NEC base cradle charges at a controlled rate — pulling the handset before the indicator clears leaves the cell partially conditioned. Run two or three complete charge-then-use cycles and talk time will reach the 1100mAh rated figure.
Handset loses DECT pairing after battery replacement
Removing the old battery cuts power completely to the handset, which can clear the pairing record stored in volatile memory on some NEC DECT platforms. The handset will show "searching" or fail to register with the base after power is restored. Re-register the handset through the base station admin menu — on most UX5000 systems this is under System → Station Assignment. Once re-registered, the handset operates normally.