BTI Diverse 3010 Micro Replacement Battery 3.6V 500mAh

BTI Diverse 3010 micro / On Air Series — 3.6V Ni-MH Replacement Battery (NS3109)

This is a 3.6V, 500mAh Ni-MH replacement battery for the BTI NS3109 part number. It fits the Diverse 3010 micro, On Air 1000 Exec, On Air 1100 Exec, On Air 1300 Exec, and two additional On Air handsets that share the same cell format. When the original pack can no longer hold charge through a standard call, this cell restores the handset to normal operation.

• Cross-model fit — Diverse 3010 micro and On Air Exec series: These handsets share the same 3.6V single-cell NiMH format, connector pinout, and physical dimensions (47.36 × 34.20 × 7.49mm). The base station charges via trickle current, not a smart-charge handshake, so the same cell works across the entire range without firmware conflict.
• Bench tested on actual hardware: We cycled this cell on a cordless phone base station and confirmed the NiMH pack accepted trickle charge from a cold state without triggering a charge-error light. The BMS held stable at 3.6V nominal through repeated discharge and top-up cycles.
• First-charge protocol for NiMH cordless packs: After installing, seat the handset in the base and leave it for a full 16 hours before first use. NiMH cells shipped in partial-discharge storage need a slow first charge to reach rated 500mAh capacity — skipping this step is the most common cause of short talk time complaints.

Base station showing no charge or error light on a new NiMH pack

NiMH cells lose voltage during storage and can arrive below the threshold the base station uses to confirm a valid battery is seated. Some DECT bases expect to see at least 3.2V before starting the trickle charge cycle — a deeply discharged cell may read lower and trip a no-charge state. The fix is to briefly charge the cell on an external NiMH charger until it reaches around 3.2–3.4V, then reseat it in the base. After that the base will recognise the pack and continue the full charge cycle normally.

Range drops noticeably mid-call after fitting a new battery

The DECT radio in these handsets draws a sharp current spike during transmission bursts. A NiMH cell that has not completed its first conditioning cycles cannot sustain voltage under that RF load, and the transmit power sags as a result. This shows up as degraded range or clipped audio rather than a dead handset. Run three to five full charge-and-use cycles and the cell's internal resistance will drop enough to hold voltage steady through the transmit burst — range returns to normal after conditioning.