Rayovac RAY55 Cordless Phone Replacement Battery 2.4V 300mAh

Rayovac RAY55 — 2.4V Ni-MH Replacement Battery

This is a 2.4V, 300mAh Ni-MH replacement battery for the Rayovac RAY55 cordless phone handset. It fits directly into the handset battery compartment and restores wireless talk functionality to your cordless phone system. Capacity is 0.72Wh, matching the original pack specification.

• RAY55 handset compatibility: The RAY55 handset runs a 2.4V NiMH cell at this exact form factor — 29.03 x 28.84 x 14.66mm. The base station charger circuit is calibrated to NiMH charge termination voltage, so the chemistry match matters as much as the physical fit.
• Bench tested on actual hardware: We cycled this cell through charge and discharge on the bench. The BMS in the base station accepted the pack without error, and charge termination triggered correctly at full capacity on the third conditioning cycle.
• First installation charge: After installing, seat the handset in the base and leave it for a full 16 hours before first use. NiMH cells ship in a partially discharged state — the slow first charge is what brings the cell to rated capacity. Skipping this step is the most common reason a new battery underperforms from day one.

Base station showing charging error on a new NiMH pack

NiMH cells lose voltage during storage. If the cell voltage drops far enough, the base station charger circuit may read it as a fault rather than a dischargeable battery. This happens because the base expects to see a minimum acceptance voltage before starting the charge cycle. The fix is straightforward: leave the handset seated in the base without interruption — the trickle charge stage will slowly bring voltage up until the main charge cycle kicks in. If the error persists after 30 minutes, remove the handset, wait 10 seconds, and reseat it to trigger a fresh charge detection cycle.

Talk time shorter than expected after the first few uses

New NiMH cells do not deliver rated capacity on the first charge cycle. The crystalline structure inside the cell needs three to five full charge-discharge cycles before it reaches full rated capacity — this is normal NiMH behaviour, not a defective cell. After each use, run the handset down in normal use rather than topping it up from half charge. By cycle four or five, talk time should reach the level the 300mAh rating reflects.