Plantronics Voyager Focus 2 Replacement Battery 3.7V 700mAh

Plantronics Voyager Focus 2 — 3.7V Li-Polymer Replacement Battery (FT523230P)

This 3.7V, 700mAh Li-Polymer battery replaces the original FT523230P cell inside the Plantronics Voyager Focus 2 wireless Bluetooth headset. It fits the over-ear stereo headset used for office and mobile calls. Capacity matches the original at 700mAh (2.59Wh).

• Voyager Focus 2 fit: The Focus 2 uses a compact Li-Polymer cell at 35.00 x 29.60 x 6.70mm. That physical footprint, combined with the 3.7V nominal rail and the FT523230P connector pinout, is what locks this battery to this headset — not just voltage alone.
• Bench tested on actual hardware: We cycled this cell through charge and discharge on the Focus 2 platform and confirmed the BMS completed its handshake with the base station. Charge acceptance was normal and the protection circuit tripped correctly at low-voltage threshold.
• First-cycle base station protocol: Seat the headset in its charging base and run a full uninterrupted charge before your first call. The Focus 2 base station logs the new cell during that first cycle — until it does, the talk-time indicator on the headset and any paired softphone will read inaccurately.

Why the Voyager Focus 2 cuts out mid-call even with a new battery

The Focus 2 runs two power-hungry systems at once — active noise cancellation and the Bluetooth radio. Under that combined draw, a cell sitting at storage voltage (typically around 3.6V) can sag below the BMS cutoff threshold before it has been fully conditioned. The headset interprets this as a depleted cell and shuts the audio. This is not a fault with the replacement cell — it resolves after two to three complete charge cycles as the cell reaches its rated capacity. Run each conditioning cycle in the base station with the headset fully seated.

Base station shows charging error after battery swap

After a battery replacement, the Focus 2 base station occasionally displays a charging fault or refuses to register the headset as charging. This happens when the BMS on the new cell has not yet completed its initialisation handshake with the base's charge controller. Remove the headset from the base, wait 10 seconds, and reseat it firmly — the contacts on the Focus 2 are recessed and a partial connection will stall the handshake. If the error persists, confirm the cell voltage is above 3.5V with a multimeter before reseating.