Dopod S600 Replacement Battery NIKI160 3.7V 1200mAh

Dopod S600 — 3.7V Li-Polymer Replacement Battery (NIKI160)

This is a 3.7V, 1200mAh Li-Polymer replacement cell for the Dopod S600 Windows Mobile PDA phone. It fits the S600 directly, matching the original cell dimensions of 44.36 × 46.50 × 6.38mm. Voltage and connector align with the OEM spec — part numbers NIKI160, 35H00103-00M, and 35H00103-01M all cross to this battery.

• S600 platform fit: The S600 uses a fixed 3.7V single-cell Li-Polymer pack with a proprietary connector and an onboard fuel gauge IC that tracks charge state. Any replacement must match the cell voltage and physical footprint exactly — this one does.
• Bench tested on actual hardware: We cycled this cell through charge and discharge on the S600 platform and confirmed the BMS accepted the cell without triggering an overcurrent or undervoltage cutoff. The fuel gauge IC initialised normally after one full cycle.
• Fuel gauge recalibration on first cycle: After swapping this cell in, run one complete discharge down to automatic shutdown, then charge uninterrupted to 100% before resuming normal use. The S600's fuel gauge IC is calibrated to the old cell's discharge curve — skipping this step causes the percentage readout to jump or misreport state of charge.

Why the S600 shuts down suddenly at 20–30% after a cell swap

The S600's fuel gauge IC uses a coulomb counter that was trained on the original cell's voltage-versus-capacity curve. A new cell has a slightly different discharge curve, so the IC underestimates how close the cell is to its minimum cutoff voltage. Under load — particularly when the GSM modem fires during a call or data sync — voltage drops sharply below 3.4V before the gauge has reported anything near zero. The processor triggers an emergency shutdown to protect the cell. One full discharge-charge calibration cycle corrects the IC's reference curve and eliminates the early cutoff behaviour.

S600 not powering on after sitting in storage

Li-Polymer cells self-discharge at roughly 2–3% per month. A device left in storage for six months or more can drop the cell below 2.5V, which trips the BMS into a protection lockout state to prevent cell damage. In lockout, the phone will not respond to the power button at all. Connect the S600 to its original charger or a USB power source and leave it for at least 30–60 minutes without pressing any buttons — the charge IC applies a trickle current that brings the cell back above the 2.8V threshold needed to release the BMS lockout before normal charging resumes.