Swissvoice eSense C8425 Compatible Battery 3.7V 600mAh

Swissvoice eSense Series — 3.7V Li-ion Replacement Battery (C8425)

This is a 3.7V, 600mAh Li-ion battery for the Swissvoice eSense cordless DECT handset. It also fits the eSense Coloe E and SV 20406288 variants. Same voltage, same footprint at 45.75 × 32.30 × 5.22mm — it drops straight into the battery compartment without modification.

• eSense handset family: The eSense, eSense Coloe E, and SV 20406288 all run off the same 3.7V single-cell Li-ion rail with an identical connector and cell footprint. One battery covers the whole family.
• Bench tested on actual hardware: We cycled this battery through charge and discharge on the eSense platform. The BMS accepted charge from the base station cradle immediately with no rejection events, and cell voltage held stable across the full discharge curve.
• First charge after fitting: Li-ion cells in DECT handsets often arrive partially discharged from storage. Seat the handset in the base and let it charge uninterrupted for a full cycle before making your first call — this lets the BMS calibrate its capacity estimate correctly from the start.

Talk time shorter than expected after fitting the new battery

A fresh Li-ion cell that has been in storage for weeks or months will not deliver full rated capacity on the first cycle. The BMS may also have an inaccurate state-of-charge reading until it completes one full charge-to-discharge cycle. Run two to three full cycles — charge until the handset indicator shows full, then use it until the low-battery alert triggers. By the third cycle, the BMS recalibrates and talk time should reflect the rated 600mAh capacity.

Handset loses pairing with the base after battery replacement

Removing the battery from a DECT handset cuts all power to the baseband chip, which can clear the stored pairing data on some eSense units. The handset then boots without a registered base and shows no line or signal bars. To fix this, press and hold the Paging or Find Handset button on the base station until the LED flashes, then follow the registration sequence on the handset — typically navigating to Menu → Settings → Register Handset. The base station PIN is usually 0000 unless it has been changed.