Nokia BL-6000C 6305 Replacement Battery 3.7V 900mAh

Nokia 6305 / 6305i — 3.7V Li-ion Replacement Battery (BL-6000C)

This is a 3.7V, 900mAh Li-ion cell built to the BL-6000C specification. It fits the Nokia 6305 and 6305i candybar-style mobile phones. Voltage and connector match the original Nokia BL-6000C exactly.

• 6305 and 6305i compatibility: Both handsets share the same battery bay dimensions, contact pitch, and 3.7V single-cell architecture. One cell fits both — no adapter or modification needed.
• Bench tested on actual hardware: We cycled this cell through full charge and discharge on a 6305 body. The BMS accepted charge from the Nokia wall adapter without error, held voltage above 3.5V through a sustained call load, and tripped protection at the expected low-voltage cutoff.
• Fuel gauge recalibration after installation: On first use, run the phone down until it shuts off automatically, then charge uninterrupted to 100%. The fuel gauge IC on the 6305 is calibrated to the old cell's discharge curve — one full cycle resets the reference points and stops erratic percentage readings.

Why the Nokia 6305 shuts down suddenly at 20–30% battery remaining

The 6305's voltage regulation circuit monitors cell voltage directly. When an aged or mismatched cell cannot sustain voltage under the load spike of an outgoing call or backlight pulse, the phone interprets the drop as a fault and cuts power — even if the fuel gauge still shows charge remaining. A new cell with lower internal resistance holds voltage through those load spikes. After one full discharge-charge cycle, the fuel gauge IC recalibrates its cutoff reference to the new cell's actual voltage curve, and the phantom shutdowns stop.

Phone won't power on after the replacement battery sat in storage

Li-ion cells self-discharge during storage. If the BL-6000C cell dropped below approximately 2.5V before installation, the BMS locks out to prevent cell damage — and the phone simply won't respond. Connect the phone to the Nokia wall charger and leave it for 15–20 minutes without pressing the power button. The charger feeds a trickle current that raises cell voltage back above the BMS re-enable threshold. Once the phone shows the charging indicator, a normal charge cycle can begin.