Pacific Bell 810 Cordless Phone Compatible Battery 3.6V 600mAh

Pacific Bell 810 / 820 Series — 3.6V Ni-MH Replacement Battery

This 3.6V, 600mAh Ni-MH battery replaces the original handset cell in Pacific Bell cordless phones, including the 810, 820, Sears 34951, and 3523403380 among others. It restores wireless talk capability to handsets that no longer hold a charge. Voltage and connector match the original pack, so no modification is needed.

• 810 and 820 series handsets: These models share the same 3.6V single-cell NiMH format, battery compartment footprint, and connector orientation — which is why one replacement covers the full range. The base station charge circuit expects this voltage window, and a matched cell keeps the charging cycle stable.
• Bench tested on actual hardware: We cycled this pack through charge and discharge on a cordless phone test rig. The BMS on these handsets accepted the cell without error flags, and voltage held steady across the full discharge curve under a simulated standby-plus-talk load.
• First charge on NiMH handset batteries: After installing, seat the handset in the base and leave it for a full 16 hours before first use. NiMH cells arrive partially discharged from storage — skipping this initial slow charge means you will never see rated capacity in early cycles.

Talk time shorter than the original battery after replacement

NiMH cells need three to five full charge-discharge cycles before they reach rated capacity — this is chemistry, not a fault with the pack. On cycle one, many users see noticeably shorter talk time and assume the battery is defective. Keep using it normally, letting the handset run down before returning it to the base each time. By cycle four or five, capacity stabilises at its rated 600mAh.

Base station shows no charge light or error light after battery swap

Pacific Bell base stations check incoming voltage before enabling the charge circuit. A new NiMH cell that has self-discharged in storage can arrive below the 3.0V threshold the base needs to recognise the pack. If the charge light does not come on within a few minutes, remove the handset, wait 30 seconds, and re-seat it firmly. If the light still does not activate, the cell voltage is too low for the base to accept — use a standalone NiMH charger at 0.1C to bring it up to at least 3.2V first.