About this replacement
Plantronics Savi W8210 / Savi 8220 — 3.7V Li-Polymer Replacement Battery (211425-01)
This 3.7V, 510mAh lithium-polymer cell replaces the original battery in the Plantronics Savi W8210, Savi 8210, and Savi 8220 wireless DECT headsets. It fits the compact battery housing inside the headset earpiece and connects via the same JST-style connector as OEM part 211425-01 (also cross-referenced as 202555-01). Capacity matches the original specification — no modification needed to fit the charging circuit.
- Savi W8210 / 8220 platform fit: Both headsets share the same battery bay, connector pinout, and BMS handshake protocol with the base station — that is why one cell covers the full model range. The charging IC in the base expects the same cell impedance signature whether the headset is docked on a W8210 or 8220.
- Bench tested on actual hardware: We ran this cell through the Savi base station charge cycle and confirmed the BMS handshake completed without a charging error. The protection circuit triggered correctly at both low-voltage cutoff and full-charge termination.
- First-cycle base station pairing: Dock the headset in the base for a complete uninterrupted charge cycle before making any calls. The base station logs the new cell's charge profile during this cycle — skipping it causes the talk-time indicator to read inaccurately for the first several uses.
Base station showing charging error after fitting a new cell
The Savi base station monitors cell voltage at the start of each dock event. If the new cell arrives at storage voltage — typically around 3.6V — the base may flag a charging fault because it reads the voltage as outside the expected range for a mid-cycle cell. This is a BMS initialisation issue, not a faulty battery. Place the headset in the base, leave it undisturbed for a full charge cycle, and the error will clear once the cell reaches 4.2V and the BMS handshake completes. If the fault persists after one full cycle, check that the headset contacts are clean and seated flat against the base cradle.
Talk time shorter than rated across the first few uses
Li-polymer cells do not deliver full rated capacity on the first charge cycle. A fresh 510mAh cell typically delivers 85–90% of rated capacity until it completes three to five full charge-discharge cycles. The Savi's combined audio processing and DECT radio draw accelerates how quickly a partially conditioned cell appears depleted. Run three full cycles — dock until the base light shows full charge, use the headset until it warns low, then redock — and talk time will stabilise near the rated figure.