About this replacement
Nokia C1 Plus — 3.8V Li-ion Replacement Battery (SP210)
This is a 3.8V Li-ion battery rated at 2400mAh (9.12Wh), built to the SP210 specification for the Nokia C1 Plus smartphone. It replaces the original cell when the device no longer holds charge through a full day of calls, messaging, and app use. Voltage, connector, and physical dimensions match the C1 Plus bay exactly — 77.05 x 59.94 x 4.28mm.
- Nokia C1 Plus fit: The C1 Plus uses a fixed 3.8V nominal rail with a low-cost charge IC. The SP210 cell matches that voltage threshold and the board's charge termination logic, so the charge IC sees a known cell profile and completes the charge cycle correctly.
- Bench tested on actual hardware: We cycled this cell through charge and discharge on the C1 Plus board. The BMS accepted the cell, the charge IC reached full termination voltage, and the fuel gauge IC stabilised after one complete cycle.
- Fuel gauge recalibration on first use: On first use after installation, run one full discharge to near shutdown, then charge uninterrupted to 100%. This gives the fuel gauge IC a complete discharge curve to map against the new cell — skipping this step causes erratic percentage readings for several days.
Sudden shutdown at 20–30% on the Nokia C1 Plus after a cell swap
The C1 Plus fuel gauge IC stores a discharge curve from the original cell. When a new cell goes in, the IC is still referencing the old curve. At 20–30% reported charge, the new cell's actual voltage may already be sagging under modem or screen load — the IC hasn't learned where the voltage cliff sits yet. The device interprets the voltage drop as a hard shutdown event rather than a low-battery warning. One full discharge-to-shutdown followed by an uninterrupted charge cycle resets the coulomb counter and resolves this. After that cycle, the IC tracks the new cell's curve and shutdown behaviour normalises.
Device not powering on after the replacement cell sat in storage
Li-ion cells self-discharge in storage. If this battery was stored for an extended period before installation and the resting voltage dropped below approximately 2.5V per cell, the BMS will lock out to prevent charging a dangerously depleted cell. The phone will show no response — no boot screen, no charging indicator. Connect the phone to a charger and leave it untouched for 15–20 minutes. Most charge ICs on budget Nokia hardware apply a trickle recovery current at around 100mA to bring the cell back above the BMS lockout threshold before switching to full charge current. If the charging indicator appears within 20 minutes, the BMS has recovered — wait for at least 15% reported charge before attempting to boot.