Sagem 690 Cordless Phone Compatible Battery 3.7V 700mAh

Sagem 690 — 3.7V Li-ion Replacement Battery (LP043048AH)

This is a 3.7V, 700mAh Li-ion replacement battery for the Sagem 690 cordless phone handset. It carries OEM part numbers LP043048AH, 253230694, and CTB104. When the original cell degrades and stops holding charge, this unit restores the handset to full working condition.

• Sagem 690 fit: The 690 handset uses a slim single-cell Li-ion pack at 3.7V with a specific connector pinout and BMS handshake tied to the base station charge circuit. This battery matches that voltage rail and physical footprint — 49mm × 30mm × 4.5mm — so the charge controller accepts it without fault codes.
• Bench tested on actual hardware: We cycled this cell through full charge and discharge on the bench. The internal BMS held the cutoff voltage steady at both ends — no early shutoff, no overcharge event. The base station charge circuit recognised the pack immediately and moved through trickle and termination phases correctly.
• First charge after install: Li-ion cells ship in a partial state of charge. Place the handset in the base for a full uninterrupted charge cycle before first use — the Sagem 690 base station uses voltage-delta detection to set termination, and interrupting early leaves the cell below rated capacity from the start.

Talk time shorter than expected after fitting the new battery

Li-ion cells arrive from storage at reduced capacity — typically 60–70% of rated. The Sagem 690 base station runs a single charge cycle, but one cycle is not always enough to bring a stored cell to its full 700mAh. Run two to three complete charge-and-use cycles before judging talk time. After the third cycle, capacity should stabilise at the rated figure. If it does not, check that the handset is fully seated in the cradle — a partial connection drops the charge current and the cell never reaches the termination threshold.

Handset fails to pair with the base after replacing the battery

Removing the old battery cuts power completely, and some DECT implementations on the Sagem 690 clear pairing data from volatile memory during a full power loss. The fix is a manual re-registration — hold the paging button on the base for five seconds until the base enters registration mode, then follow the handset menu to re-pair. No configuration is permanently lost; only the RF link token needs to be re-established. Once paired, the handset stores the link in non-volatile memory and survives future battery swaps.