About this replacement
Sagem D16T / D18T Series — 2.4V Ni-MH Replacement Battery (2SN-AAA55H-S-JP1)
This is a 2.4V, 700mAh Ni-MH battery replacing part number 2SN-AAA55H-S-JP1 in Sagem cordless handsets. It fits the D16T, D16T Duo, D16T Duo 2, and D18T. The pack slides into the handset battery compartment and connects to the base station charging contacts as the original did.
- D16T and D18T series compatibility: These models share the same 2.4V two-cell NiMH pack format, connector pitch, and BMS handshake with the base station — one replacement covers the full range listed above.
- Bench tested on actual hardware: We cycled this pack through charge and discharge on a D16T handset base. The base accepted charge immediately, voltage climbed to 2.8V at full charge, and the BMS held within normal NiMH limits across five full cycles.
- First charge after install: After fitting this pack, place the handset in the base cradle for a full 16 hours before using it. NiMH cells at storage charge need that slow first cycle to reach rated 700mAh capacity — cutting it short means the first few sessions will feel short.
Talk time shorter than expected after the first few charges
NiMH cells leave storage at a partial charge state, and the first one to three cycles will not deliver full rated capacity. This is a chemistry behaviour, not a fault with the pack. Each full charge-discharge cycle conditions the cells and unlocks more capacity. By cycle four or five, the pack should reach close to its rated 700mAh output.
Range dropping mid-call on the D16T after battery swap
DECT handsets draw a burst of current each time the radio transmits. If the NiMH pack voltage sags under that RF load, the transmit power falls and range shrinks noticeably. This usually means the pack has not completed its initial conditioning cycles and the cells are not yet delivering full current. Run three to five complete charge-discharge cycles and the voltage sag under RF load will reduce. If range stays poor after five cycles, check that the handset contacts and base cradle contacts are clean and making solid contact.