TP-Link Neffos C5L Compatible Battery NBL-45A2000 3.8V

TP-Link Neffos C5L / TP601 Series — 3.8V Li-ion Replacement Battery (NBL-45A2000)

This is a 3.8V Li-ion replacement battery rated at 1750mAh (6.65Wh), built to the NBL-45A2000 specification. It fits the Neffos C5L, Neffos C5L Dual SIM, TP601E, and TP601C. If the original cell is swelling, draining abnormally fast, or failing to hold a charge, this is a direct cell swap at the correct voltage and footprint.

• TP601 platform fitment: The C5L, C5L Dual SIM, TP601E, and TP601C all share the same battery bay dimensions and connector pinout. The BMS on these variants uses the same charge profile, so the NBL-45A2000 cell communicates correctly with the charge IC across the whole TP601 family.
• Bench tested on actual hardware: We ran this cell through a full charge and discharge cycle on a TP601-series device. The BMS accepted the cell on first connection, the charge IC stepped through trickle, CC, and CV phases without fault, and the protection circuit tripped cleanly at low-voltage cutoff.
• Fuel gauge recalibration after swap: After installing this cell, run one complete discharge to auto-shutoff followed by a full uninterrupted charge before normal use. The Neffos C5L fuel gauge IC was calibrated against the original cell's discharge curve — skipping this step leaves the coulomb counter reporting stale data, which causes erratic percentage readings in the first few days.

Sudden shutdown at 20–30% on the Neffos C5L after a cell swap

This is the most reported failure mode after replacing the NBL-45A2000 cell, and it is not a defective battery. The fuel gauge IC on the TP601 platform stores a learned discharge curve from the original cell. When a fresh cell with a steeper voltage cliff hits the modem or display load spike, the IC sees a voltage dip it misreads as near-empty and cuts power. Running two full discharge-to-shutoff and charge-to-100% cycles forces the coulomb counter to relearn the new cell's curve. After calibration, the shutdown threshold tracks correctly and the premature cutoffs stop.

Phone stays at 0% and will not boot after the replacement cell sat in storage

Li-ion cells that drop below 2.5V trigger a BMS lockout to prevent cell damage — this is common when a replacement battery has been sitting in warehouse stock. The Neffos C5L will show 0%, refuse to boot, and may not respond to the charger for the first several minutes. Connect the original charger and leave it plugged in for 15–20 minutes before attempting to power on. The BMS trickle-charges the cell back above the 2.7V recovery threshold before handing off to the main charge IC — once it crosses that voltage, the phone will boot normally.