UniData ICW-1000G VoIP Phone Compatible Battery 3.7V 1100mAh

UniData ICW-1000G / WPU-7800 — 3.7V Li-ion Replacement Battery (ICW-1000G)

This is a 3.7V, 1100mAh Li-ion battery for the UniData ICW-1000G cordless VoIP handset and WPU-7800. It powers the wireless handset so calls stay connected within range of the base station. When the original cell can no longer hold a charge, this replacement restores full handset operation.

• ICW-1000G and WPU-7800 compatibility: Both handsets share the same 3.7V single-cell Li-ion pack with identical connector pinout and physical footprint — 53.26 × 34.10 × 6.10mm. The BMS parameters match what the base station charger circuit expects, so the charging handshake completes normally.
• Bench tested on actual hardware: We cycled this cell through charge and discharge on the ICW-1000G platform. The BMS held the charge curve within spec and terminated correctly at full capacity without triggering a protection cutoff.
• First-use charge protocol for VoIP backup function: After installing, power cycle the handset and place it on the base for a full 4-hour charge before testing any backup or outage function. The phone's firmware will not activate backup power from a partially charged cell — it checks for a minimum state of charge before committing the battery to emergency use.

ICW-1000G handset not switching to battery during a power outage

The ICW-1000G base station monitors battery state of charge before it will route power through the backup circuit. If the replacement cell arrived partially discharged from storage — common with Li-ion below 3.5V — the firmware flags it as insufficient and keeps the phone off during an outage test. This is not a fault with the battery or the handset. Place the handset on the cradle for a full 4-hour charge, then retest. The backup circuit will engage once the cell reads above the firmware's minimum threshold, typically around 3.6V.

Low battery warning appearing immediately after installing a new cell

Li-ion cells lose charge during storage and shipping, so a voltage of 3.4–3.5V on arrival is normal. The ICW-1000G handset reads this as a low-battery state and displays the warning right away — it is not a sign of a defective battery. Return the handset to the base station and allow it to charge uninterrupted. The warning clears once the cell climbs above approximately 3.7V, which the base charger reaches within the first hour of charging.