Panasonic HHR-P509 Cordless Phone Replacement Battery 2.4V 1200mAh

Panasonic TG2650 / TG2670 / TG2680 / TG2690 Series — 2.4V Ni-MH Replacement Battery (HHR-P509)

This is a 2.4V, 1200mAh Ni-MH replacement battery for the Panasonic TG2650 and related cordless phone handsets. It replaces OEM part numbers HHR-P509 and HHR-P509A, among others. The battery slots into the handset battery compartment and restores talk time and standby operation to a handset with a depleted or failed original pack.

• TG2650 / TG2670 / TG2680 / TG2690 handset fit: These models share the same 2.4V Ni-MH cell configuration, physical dimensions, and connector orientation, which is why a single battery covers the full range. The handset charging circuit expects a consistent internal resistance profile that Ni-MH cells in this form factor deliver.
• Bench tested on actual hardware: We cycled this battery through charge and discharge on Panasonic cordless handset hardware. The BMS in the base station accepted the pack without fault codes, and capacity tracked within spec by the third conditioning cycle.
• First-charge protocol for NiMH cordless packs: After fitting this battery, seat the handset in the base for a continuous 16-hour charge before first use. NiMH cells shipped in storage discharge need a slow trickle charge to reach rated capacity — a short first charge will leave you with noticeably less talk time from day one.

Talk time shorter than the original battery after replacement

NiMH cells require three to five full charge and discharge cycles before they reach rated capacity. A replacement pack that ships after months in storage will underperform on the first few uses — this is a chemistry characteristic, not a defect. Run the handset until it drops out, then charge it fully in the base for 16 hours. Repeat this three times and talk time will align with the 1200mAh rating.

Base station charge light not activating on a new pack

Panasonic bases check the incoming voltage from the handset battery before starting the charge cycle. A pack that has discharged below roughly 1.8V total during storage may fall outside the base's acceptance window, causing the charge indicator to stay dark or flash an error. Remove the handset, leave it seated in the base unpowered for two minutes, then reseat it firmly — this clears the handset's internal state. If the base still does not respond, a brief charge from a compatible external NiMH charger can raise the cell voltage to approximately 2.0V so the base circuit accepts it.