Cidco B650 Cordless Phone Compatible Battery 3.6V 1200mAh

Cidco B650 / CD900 / CL900 Series — 3.6V Ni-MH Replacement Battery

This is a 3.6V, 1200mAh Ni-MH replacement battery for Cidco cordless phone handsets. It fits the B650, CD900, CL900, CL901, and several additional models in the same series. When the original pack no longer holds a charge, this battery restores full handset portability without replacing the phone system.

• B650 / CD900 / CL900 series compatibility: These models share the same 3.6V three-cell Ni-MH configuration, connector pinout, and physical footprint — 50.43 × 42.54 × 14.40mm. The handset's charging circuit expects a specific voltage window, and this pack matches it.
• Bench tested on actual hardware: We cycled this pack through charge and discharge on compatible Cidco handsets. The BMS accepted the battery without fault codes, and voltage held steady through full standby and active transmit loads.
• First-charge protocol for Ni-MH cordless packs: After installing, seat the handset in the base and leave it for a full 16 hours before first use. Ni-MH cells shipped in partial-charge storage states require a slow initial charge to reach rated 1200mAh capacity — skipping this step means the first several cycles will underperform.

Range dropping on the CL900 and CL901 after a battery swap

DECT handsets regulate transmit power based on available voltage from the battery. A fresh Ni-MH pack that hasn't been through conditioning cycles will sag under RF load — the handset sees lower voltage and pulls back transmit strength. This looks like reduced range but isn't a hardware fault. Three to five full charge-discharge cycles bring the cells to rated capacity and stabilise voltage delivery under load. After conditioning, transmit power returns to normal operating levels.

Base station showing a charging error or fault light on a new pack

Ni-MH batteries discharged during storage can arrive below 3.0V — some Cidco base stations read this as an invalid or missing battery and display an error light instead of beginning a charge cycle. Remove the handset, wait 10 seconds, then reseat it firmly. If the error persists, the base needs to detect a minimum threshold voltage before it initiates charging — try placing the handset in a secondary handset charger if available, or leave it seated for 30 minutes to allow trickle current to bring the pack above the acceptance threshold of approximately 3.2V.