Aastra NEXSPAN Cordless Phone Replacement Battery 3.6V 700mAh

Aastra NEXSPAN M910 M915 M920 Series — 3.6V Ni-MH Replacement Battery

This 3.6V, 700mAh Ni-MH battery replaces the original handset battery in the Aastra NEXSPAN cordless phone system. It fits the NEXSPAN, M910, M915, and M920 handsets, restoring cordless operation when the original cell no longer holds a charge. Capacity is rated at 2.52Wh — matching OEM spec for this handset family.

• NEXSPAN handset family fit: The M910, M915, M920, and NEXSPAN base-series handsets share the same battery bay dimensions, connector pin-out, and 3.6V NiMH charge circuit. One cell works across all these models without modification.
• Bench tested on actual hardware: We cycled this cell through the NEXSPAN base station charge circuit and confirmed the BMS accepts the pack without triggering an error state. Charge termination behaved correctly at full capacity.
• First-charge protocol for NiMH handsets: After installing, seat the handset in the base and leave it for a full 16 hours before first use. NiMH cells ship partially discharged — skipping this slow initial charge means the cell never reaches rated capacity and talk time suffers from the first call.

Talk time shorter than original battery after replacement

New NiMH cells do not deliver full capacity on the first charge cycle — this is normal chemistry, not a fault. The cell needs three to five full charge-and-discharge cycles before it reaches the rated 700mAh. Each cycle, available capacity steps up noticeably. Run the handset to low battery, return it to the base for a full 16-hour charge, and repeat — by cycle five, talk time should match or exceed the original pack.

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

NEXSPAN base stations use a voltage-threshold check before initiating a charge cycle. A cell that has sat in storage can drop below 3.0V, which the base reads as a fault rather than a flat battery. Remove the handset, wait 30 seconds, and reseat it firmly — this resets the charge circuit. If the error persists, measure the battery terminals with a multimeter; anything below 2.8V requires a trickle pre-charge to bring the cell back above the acceptance threshold before the base will charge normally.