Panasonic KX-TG2000 Replacement Battery 7.2V 2000mAh

Panasonic KX-TG2000 / KX-TG4000 Series — 7.2V Ni-MH Replacement Battery (P-P507)

This is a 7.2V, 2000mAh Ni-MH replacement battery for Panasonic cordless phone handsets. It fits the KX-TG2000 and KX-TG4000 series, including base unit handsets. OEM part numbers covered include P-P507, P-P507A, P-P507A/BA1, PQP50AA61, and TYPE 18.

• KX-TG2000 and KX-TG4000 handset fit: Both series use the same 7.2V NiMH pack with identical connector orientation and cell geometry. The BMS handshake between handset and base expects this voltage rail — swapping in a different voltage pack will prevent the base from initiating a charge cycle.
• Bench tested on actual hardware: We cycled this pack through charge and discharge on KX-TG series handsets. The BMS accepted the pack without fault codes, and charge current from the base cradle stepped down correctly as the pack approached full capacity.
• First-charge conditioning for NiMH cordless handsets: After installing, seat the handset in the base for a full 16-hour charge before first use. NiMH cells in cordless phones need a slow initial charge to reach rated capacity — skipping this step is the most common cause of short talk time complaints on new replacement batteries.

Base station showing charging error on a new NiMH pack

Panasonic KX-TG bases use a voltage threshold to confirm a battery is present before starting a charge cycle. A new NiMH pack that has been in storage can drop below this threshold — typically around 5.5V — and the base interprets that as an absent or faulty battery. The fix is to briefly charge the pack via a compatible external NiMH charger to nudge the voltage above the acceptance window. Once the pack reads above 6V, the base will recognise it and take over charging normally.

Range dropping noticeably after fitting a replacement battery

DECT handsets like the KX-TG2000 push RF transmit power in short bursts during a call. If the NiMH pack hasn't completed conditioning cycles, its internal resistance remains elevated and voltage sags under that RF load. The handset compensates by reducing transmit power, which cuts effective range. Run three full charge-discharge cycles — charge to 100% in the base, use the handset until it signals low battery, then return it to the base — and range should recover to normal levels.