Oregon Scientific WW338 Replacement Battery 3.6V 700mAh Ni-MH

Oregon Scientific WW338 / WR602 — 3.6V Ni-MH Replacement Battery

This is a 3.6V, 700mAh Ni-MH rechargeable battery for the Oregon Scientific WW338 and WR602 cordless phone handsets. It slots into the handset battery compartment and powers the DECT radio, speaker, and display. Dimensions are 45.90 × 31.20 × 10.70mm — confirm these match your compartment before ordering.

• WW338 and WR602 compatibility: Both handsets run the same 3.6V three-cell Ni-MH pack on an identical voltage rail with the same connector footprint, so one battery covers both models without modification.
• Bench tested on actual hardware: We cycled this pack through charge and discharge on the base station circuit and confirmed the protection circuit holds the cell group within the voltage window the base charger expects, avoiding false charge-error flags.
• First charge on the base station: Place the handset in the base immediately after installing this battery and leave it for a full 16 hours before first use. Ni-MH cordless phone cells need a slow initial trickle charge to reach rated 700mAh capacity — skipping this leaves usable capacity noticeably short for the first several cycles.

Range dropping mid-call after fitting a new Ni-MH pack

Ni-MH cells that have not been fully conditioned show a steeper voltage sag under RF transmit load. The WW338 DECT radio draws a brief current spike each time it transmits a burst — if the cell voltage dips too far during that spike, transmit power drops to protect the circuit. This reads to the user as reduced range or a choppy signal, even when the battery indicator shows full. Running three to five full charge and discharge cycles brings internal resistance down and keeps the voltage stable under that transmit load.

Base station charge light not coming on after battery swap

A Ni-MH pack that has self-discharged during storage can sit below the voltage threshold the base charger uses to detect a valid battery. The base sees what looks like a short circuit rather than a dischargeable cell and refuses to begin the charge cycle. To recover it, check the open-circuit voltage across the pack terminals — if it reads below approximately 3.0V, the cells need a brief external boost charge at a low rate (around 50mA) to lift them above the detection floor. Once the pack reads above 3.2V, seat the handset in the base and the charge light should activate normally.