ITT PC1600 Cordless Phone Replacement Battery 3.6V 1200mAh

ITT PC1600 / PC1700 / PC1800 — 3.6V Ni-MH Replacement Battery

This is a 3.6V 1200mAh Ni-MH rechargeable battery for the ITT PC1600, PC1700, and PC1800 cordless phone handsets. It slots into the handset battery compartment and restores power to units where the original cell no longer holds a usable charge. Voltage and capacity match the original spec exactly.

• PC1600, PC1700, and PC1800 compatibility: These three ITT handsets share the same 3.6V battery bay, connector orientation, and cell footprint — 42.40 × 49.90 × 14.40mm — so one cell suits all three models without modification.
• Bench tested on actual hardware: We ran this cell through full charge and discharge cycles on the bench. The NiMH chemistry accepted charge cleanly from the base station, and the BMS held voltage steady across standby and active RF transmission loads.
• First-charge conditioning on NiMH handsets: After installing, seat the handset in the base and leave it for a full 16 hours before first use. NiMH cells shipped in partial-charge storage state won't reach rated 1200mAh capacity until the base station completes a slow, uninterrupted first charge cycle.

Base station showing no charge or error light with a new NiMH pack

NiMH batteries lose voltage during storage and can arrive below the threshold the ITT base station expects before initiating a charge cycle. The base reads the resting voltage, and if it's too low, the charging circuit won't engage — so the handset just sits there with no charge indicator. To recover, remove the battery, let it rest at room temperature for 30 minutes, then re-seat it firmly in the handset and return it to the base. If the base still won't start a charge cycle, check that the handset contacts and base cradle contacts are clean and making solid connection.

Talk time shorter than expected after fitting the replacement cell

Short talk time on the first few cycles is normal behaviour for NiMH chemistry — it takes three to five full charge and discharge cycles before the cell reaches its rated 1200mAh capacity. During those early cycles, the crystalline structure inside the cell is still conditioning, and capacity reads low. Run the handset down to the low-battery warning, then return it to the base for a full uninterrupted charge — repeat this process across five cycles. By cycle five, talk time should stabilise at the rated level; if it doesn't, check that the base station is delivering a continuous charge rather than dropping in and out.