Manta MS1701 Replacement Battery 3.7V 550mAh JB-4C

Manta MS1701 / TEL2405 / TEL2408 — 3.7V Li-ion Replacement Battery (JB-4C)

This is a 3.7V 550mAh Li-ion cell replacing part number JB-4C in the Manta MS1701, TEL2405, and TEL2408 smartphones. It targets phones that no longer hold charge through a normal day due to cell degradation. Capacity is 550mAh (2.04Wh) — identical to the original specification.

• MS1701, TEL2405, TEL2408 fit: These three models share the same battery bay dimensions (53.00 × 34.00 × 4.80mm), connector pinout, and BMS handshake protocol — one cell fits all three without modification.
• Bench tested on actual hardware: We cycled this cell through full charge and discharge on the MS1701 platform. The BMS accepted the cell without error flags, and charge IC communication stayed stable across the full voltage range from 3.0V to 4.2V.
• First-cycle fast charge lockout: On first use after installation, disable fast charging for one complete discharge-charge cycle. This lets the fuel gauge IC recalibrate against the new cell's discharge curve before high-current charging pushes into an uncalibrated cell.

Why the MS1701 reports wrong battery percentage after a cell swap

The fuel gauge IC on the MS1701 stores a discharge curve learned from the old cell. When a new cell goes in, that stored curve no longer matches the actual cell chemistry — so the OS reads percentage from the wrong reference. The gauge IC needs one full uninterrupted discharge down to automatic shutdown, then a full charge to 100%, to build a new baseline. Until that cycle completes, percentage readings can be off by 10–20 points and the phone may behave as if capacity is lower than it actually is.

Sudden shutdown at 20–30% on the replacement cell

This happens when the modem or screen draws a current spike the cell cannot sustain at that state of charge — voltage drops below the BMS cutoff threshold, and the phone shuts off even though the gauge still shows charge remaining. It is a fuel gauge calibration problem, not a faulty cell. Run one full discharge-to-shutdown cycle without interruption, then charge uninterrupted to 100%. After that cycle, the coulomb counter resets to the new cell's actual capacity and the cutoff voltage cliff at 20–30% disappears.