Radio Shack 239069 Replacement Battery 3.6V 600mAh Ni-MH

Radio Shack 239069 / 23956 — 3.6V Ni-MH 600mAh Replacement Battery

This 3.6V, 600mAh Ni-MH battery replaces the handset pack in Radio Shack cordless phones including models 239069, 23956, 3N270AA-MRX-R, and 433215. It fits the handset's internal bay and connects to the same charging circuit the original pack used. Capacity is sourced from product data at 600mAh (2.16Wh).

• Multi-model fit — 239069 series: These Radio Shack handsets share a common 3.6V three-cell NiMH bay and the same connector orientation. The base station's charge circuit targets the same voltage range across the range, so one pack covers all listed models without modifications.
• Bench tested on actual hardware: We cycled this pack through charge and discharge on a NiMH-compatible tester. The BMS accepted charge from a standard 3.6V trickle circuit without tripping, and voltage held stable across the full discharge curve before the low-voltage cutoff triggered cleanly.
• First-charge protocol for NiMH cordless handsets: After installing, seat the handset in the base cradle and leave it for a full 16 hours before making any calls. NiMH cells shipped in partial-discharge state need this slow initial charge to align cell capacity — skipping it compresses the usable voltage window from the first cycle.

Base station charge light not activating on a new NiMH pack

Radio Shack base stations use a delta-V detection circuit to confirm a battery is present and accepting charge. A new NiMH pack that has sat in storage can drop below 3.0V, which puts it outside the window the base expects at first contact. The base interprets this as a fault rather than a discharged cell and shows no charge light or an error indicator. To recover, some handsets accept a brief top-up from a standalone NiMH charger at 1.2V per cell — bringing each cell above 1.1V — before seating in the base.

Handset losing range within the first week after battery swap

DECT handsets modulate transmit power based on available voltage from the battery. A freshly installed NiMH pack that hasn't completed conditioning cycles will sag under the RF transmit load, dropping voltage faster than a fully conditioned cell. The radio drops to a lower power mode or loses sync with the base when pack voltage sags below roughly 3.2V under load. Running three to five full charge-and-use cycles brings the cells to rated capacity and stabilises transmit voltage throughout each call.