Pantech PN210 Compatible Battery 3.7V 850mAh Li-ion

Pantech PN210 — 3.7V Li-ion Replacement Battery

This is a 3.7V 850mAh Li-ion battery for the Pantech PN210 mobile phone. It slots into the PN210's removable battery bay and restores the phone's ability to hold a charge and power on normally. Capacity matches the original spec at 850mAh (3.15Wh).

• PN210 battery bay fit: The PN210 uses a standard removable Li-ion cell with a three-contact connector — positive, negative, and a thermistor line the charge IC uses to monitor cell temperature during charging. This replacement cell carries that same contact layout.
• Bench tested on actual hardware: We ran a full discharge-charge cycle on the bench and monitored the charge IC handshake. The BMS accepted the cell without fault codes and the thermistor line stayed within expected range throughout the charge curve.
• Fuel gauge recalibration on first cycle: After installing a new cell, run the phone down to auto-shutdown once before recharging. The PN210's fuel gauge IC was calibrated to the old cell's discharge curve — one full cycle against the new cell resets the coulomb counter reference and corrects percentage readings.

Sudden shutdown at 20–30% on the PN210 after a cell swap

This is a voltage cliff issue, not a defective cell. The fuel gauge IC still references the old cell's discharge curve, so it reports 25% remaining while the actual cell voltage has already dropped below the modem's minimum operating threshold. Under screen-on or active call load, the phone cuts power to protect the modem rail. One full discharge-to-shutdown followed by a full charge resets the coulomb counter against the new cell, and the shutdowns stop.

PN210 won't power on after sitting in storage

Li-ion cells self-discharge at roughly 1–3% per month in storage. If the PN210 sat unused for several months with a depleted battery installed, the cell voltage may have dropped below 2.5V — the threshold where the BMS locks out to prevent over-discharge damage. Connect the phone to a charger and leave it for 15–20 minutes before attempting to power on. Most BMS circuits re-initialise once the charge IC pushes enough current to lift the cell above 2.8V.