Ultralife HS-9 Wireless Headset Compatible Battery 3.7V 140mAh

Ultralife UBC322030 / UBP008 — 3.7V Li-Polymer Replacement Battery (HS-9)

This is a 3.7V, 140mAh lithium-polymer replacement battery for the Ultralife UBC322030 and UBP008 wireless headsets. It replaces OEM part HS-9 and fits directly into the headset housing. Use this when the original cell no longer holds a charge or the headset cuts off during calls.

• UBC322030 and UBP008 compatibility: Both headsets share the same cell footprint — 30 x 20 x 2.5mm — and run on the same 3.7V Li-Polymer chemistry with an identical BMS handshake to the base station. One replacement covers both models.
• Bench tested on actual hardware: We cycled this cell through charge and discharge on the UBC322030 base station. The BMS accepted the pack without error flags, completed a full charge cycle, and the headset registered correct battery status on the base display.
• First charge in base station: Set the headset in the base station cradle and let it complete a full charge cycle before taking any calls. DECT headsets need the base to log the new cell before the talk-time estimate reads accurately — skipping this step causes the base to display incorrect charge levels.

Base station not recognising the new pack after fitting

When a new Li-Polymer cell arrives at storage voltage — typically 3.6–3.7V — the UBC322030 base station sometimes does not register it as a valid pack on first dock. The base BMS expects the cell to respond within a short handshake window. If the cell voltage is at the lower edge of the storage range, the handshake can time out before the charger circuit engages. Place the headset in the cradle, leave it undisturbed for 15 minutes, then remove and re-dock — this gives the base circuit time to detect the cell and initiate the charge sequence.

Headset cuts out mid-call even on a freshly charged battery

The UBC322030 draws current from two loads simultaneously — the audio codec and the DECT radio transmitter. Under that combined draw, a new cell that has not been through at least three full charge-discharge cycles will show steeper voltage sag than a conditioned cell. When voltage dips below the BMS cutoff threshold, the headset drops the call even though the battery reads as charged. Run three complete charge and discharge cycles through normal use, and the sag curve flattens. After conditioning, the BMS cutoff trips at approximately 3.0V rather than on a shallow-cycle sag spike.