V Tech LS5101 Cordless Phone Replacement Battery 3.6V 700mAh

V Tech LS5101 / LS5105 / LS5145 — 3.6V Ni-MH Replacement Battery

This is a 3.6V, 700mAh Ni-MH rechargeable battery for the V Tech LS5101, LS5105, and LS5145 cordless phone handsets. It slots into the handset battery compartment and restores power to phones that no longer hold a usable charge. Capacity is 2.52Wh, matching the original specification.

• LS5101 / LS5105 / LS5145 compatibility: These three handsets share the same 3.6V battery bay, connector orientation, and NiMH charging circuit. One battery fits all three without modification.
• Bench tested on actual hardware: We cycled this battery through the LS5101 charging circuit and confirmed the BMS accepted charge from the base station without error. Voltage at full charge measured within the expected NiMH range for this cell configuration.
• First charge on the LS5101 series: After installing, seat the handset in the base and leave it for a full 16 hours before first use. NiMH cells in cordless phone packs need a slow initial charge to reach rated capacity — skipping this step means the first few talk sessions will feel short.

Talk time shorter than original battery after replacement

NiMH cells ship in a partially discharged state and need three to five full charge-and-use cycles before they reach rated capacity. On the first cycle, the battery will feel noticeably weaker than the old one at its best. Each full cycle through the LS5101 charging circuit conditions the cells further. By cycle five, capacity typically stabilises at or near the 700mAh rating.

Base station showing no charge or error light after swap

NiMH batteries can drop to very low voltages during storage, and some DECT base stations reject packs that fall below their acceptance threshold. The LS5101 base charges by detecting a minimum voltage before engaging the charge circuit. If the light stays off or shows an error, remove the handset, wait 30 seconds, and reseat it firmly — the base sometimes needs a second detection attempt. If the problem persists, check the battery contacts are clean and the voltage at the pack terminals is not reading below 3.0V.