Philips TSU-9800 Remote Replacement Battery 3.7V 2200mAh

Philips Pronto TSU-9800 Series — 3.7V Li-Polymer Replacement Battery (310420052281)

This 3.7V, 2200mAh Li-Polymer battery replaces the internal rechargeable cell in the Philips Pronto TSU-9800 and TSU-9800I advanced programmable remote controls, along with the RC9800I Multimedia Control Panel and Pronto PC9800I/17. The original cell degrades after repeated charge cycles, causing the remote to lose range or stop holding a charge. This replacement matches the OEM voltage, capacity, and form factor of part number 310420052281.

• TSU-9800 series compatibility: The TSU-9800, TSU-9800I, PC9800I/17, and RC9800I share the same internal battery bay, connector, and 3.7V single-cell BMS architecture — which is why one cell covers all five variants in this line.
• Bench tested on actual hardware: We ran this cell through the Pronto's BMS handshake and confirmed charge acceptance at the correct 4.2V cutoff. The BMS did not flag any cell rejection errors during initial conditioning.
• Connector seating on the TSU-9800: The JST-style connector on this cell must click fully into the socket before closing the rear panel. A half-seated connector causes intermittent power loss that looks like a dead battery — press until you hear the click.

Why the Pronto TSU-9800 stops holding a charge after 2–3 years

Li-Polymer cells in always-docked remotes degrade faster than cells that go through full discharge cycles. The TSU-9800 typically sits in its charging cradle continuously, which keeps the cell at 100% — a state that accelerates cathode degradation in Li-Polymer chemistry. After 300–500 charge cycles, or roughly 2–3 years of daily use, capacity drops below the threshold the Pronto's BMS considers a valid charge. At that point the remote may show a full charge indicator but lose power within hours of leaving the cradle.

Pronto TSU-9800 IR range drops sharply after battery replacement

If the remote now requires line-of-sight or closer range than before, the new cell may not be fully charged from the factory — Li-Polymer cells ship at storage voltage, typically around 3.6–3.7V, not the 4.2V full-charge level. The IR LED driver in the TSU-9800 draws peak current at transmission; a cell below full charge cannot sustain that burst cleanly, which cuts effective range. Place the remote in the charging cradle for a full charge cycle before use, and verify the charge indicator reaches its maximum state before testing range.