GP T279 Cordless Phone Compatible Battery 3.6V 600mAh

GP T279 / T301 Series — 3.6V Ni-MH Replacement Battery (60AAH3BMU)

This is a 3.6V, 600mAh Ni-MH battery pack for GP cordless phone handsets. It replaces part numbers T279, T301, 60AAH3BMU, 30AAAM3BML, 50AAK3BML, 60AAH3BML, and 75AAH3BMJZ. If your handset no longer holds charge or drops calls mid-conversation, this pack restores the handset to working condition.

• T279 and T301 platform fit: These part numbers share the same cell count, voltage rail, and connector format. The 3.6V nominal output matches the handset's charging circuit directly — no adaptation needed between variants.
• Bench tested on actual hardware: We cycled this pack through charge and discharge on the bench. The cells accepted charge cleanly at the 3.6V threshold and the voltage profile stayed consistent across the first five cycles.
• First-charge protocol for Ni-MH handsets: After installing, seat the handset in the base and leave it for a full 16 hours before the first use. Ni-MH cells in cordless phone packs need a slow initial charge to reach rated capacity — skipping this step is the main reason replacement batteries appear to underperform early on.

Base station showing no charge or error light on a new Ni-MH pack

Fresh Ni-MH packs often ship partially discharged after months in storage. Some cordless base stations check the incoming pack voltage before starting a charge cycle — if the pack sits below roughly 3.0V, the base may refuse to charge or show a fault light. This is a voltage threshold check, not a fault with the battery or base. To recover, some users briefly charge the pack externally at a low rate to bring it above the base's acceptance floor. Once the pack reads above 3.2V, the base typically recognises it and begins a normal charge cycle.

Talk time shorter than expected after the first few charges

Ni-MH cells do not deliver full rated capacity on the first charge cycle — this is normal chemistry behaviour, not a defective pack. Rated capacity of 600mAh is typically reached after three to five full charge and discharge cycles. Each cycle conditions the cells and allows the electrolyte to distribute evenly across the plates. Run the handset until the low-battery indicator activates, then return it to the base for a full charge — repeat this three times and talk time should stabilise at the rated level.