About this replacement
Swissvoice ePure / ePure fulleco DUO / L7 — 3.7V Li-ion Replacement Battery (043048)
This 3.7V, 650mAh lithium-ion battery replaces the original pack in the Swissvoice ePure, ePure fulleco DUO, and L7 cordless DECT handsets. It matches OEM part numbers 043048 and SV20405855. When your handset no longer holds a charge or powers on fully, this is the direct swap.
- ePure, ePure fulleco DUO, and L7 compatibility: All three handsets share the same 3.7V Li-ion cell format, connector pinout, and BMS handshake protocol — which is why one battery part number covers the full range. Swapping across these models carries no risk of voltage mismatch or communication error with the base station.
- Bench tested on actual hardware: We cycled this battery through charge and discharge on the ePure platform. The BMS held the cutoff voltage correctly, accepted charge from a standard base cradle without triggering error states, and maintained stable standby draw through multiple cycles.
- First-charge protocol for Li-ion cordless handsets: After installing, seat the handset in the base cradle and leave it for a full uninterrupted charge before first use. Li-ion cells shipped in storage state need one complete charge cycle to let the BMS calibrate its state-of-charge register accurately — skipping this causes the handset to report incorrect battery level from day one.
Talk time shorter than expected on the ePure after a battery swap
A freshly installed Li-ion cell ships partially discharged and with an uncalibrated BMS. The handset reads state-of-charge from the BMS register, not from a live voltage measurement — so if the register hasn't been set by a full charge cycle, the phone will both underestimate remaining capacity and cut off early. Run two or three full charge-to-discharge cycles through the base cradle. After the third cycle, the BMS register stabilises and talk time reaches the rated capacity of 650mAh.
Handset not pairing with base after battery replacement
Removing the battery from a DECT handset drops power to the DECT module, which can flush the pairing record stored in volatile memory on some ePure variants. The handset comes back up with no registered base, so it sits idle rather than connecting. To re-pair, hold the handset's page or register button while pressing the pairing button on the base unit — the exact sequence is printed on the underside of the base. Once paired, the handset retains the registration even through future battery swaps as long as the new battery is inserted before power is fully lost.