Manta MS1701 JB-4C Replacement Battery 3.7V 900mAh

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

This is a 3.7V, 900mAh Li-ion cell replacing the JB-4C battery in the Manta MS1701, TEL2405, and TEL2408 smartphones. It restores power to devices where the original cell has degraded, swollen, or stopped holding a charge. Dimensions are 53.00 × 34.00 × 4.80mm — confirm these against your existing cell before installing.

• MS1701, TEL2405, TEL2408 fit: All three models share the same JB-4C form factor, connector pinout, and voltage rail. The BMS protection circuit on each device expects a 3.7V nominal cell with the same physical footprint — swapping between models is not required, but the cell seats identically in each.
• Bench tested on actual hardware: We cycled this cell through full charge and discharge on the bench. The BMS accepted the cell without triggering overcurrent or over-voltage cutoff. Charge termination occurred correctly at 4.2V.
• Fuel gauge recalibration after install: On first use, disable fast charging if your variant supports it, then run one complete discharge-to-charge cycle. This lets the fuel gauge IC map the new cell's discharge curve before reporting accurate percentages — skipping this step is why most users see percentage jumps in the first two days.

Sudden shutdown at 20–30% on the Manta MS1701 after a cell swap

A new 900mAh cell has a different internal resistance profile than the worn cell the fuel gauge IC was calibrated against. Under peak load — screen on, mobile data active — voltage can sag below the BMS cutoff threshold even when the gauge still reads 20–30%. The phone cuts out not because the cell is empty, but because instantaneous voltage dropped under load. One full discharge-charge cycle recalibrates the coulomb counter and usually resolves this within two to three cycles.

Battery percentage jumping erratically after replacement

The fuel gauge IC stores a learned discharge curve from the previous cell. After swapping to a fresh 900mAh cell, the stored curve no longer matches actual cell behaviour — so the reported percentage jumps as the IC tries to reconcile mismatched data points. This is not a faulty cell. Charge the phone to 100%, allow it to discharge fully without interruption, then charge back to 100% uninterrupted. After that single cycle, the IC rewrites its reference curve against the new cell and percentage reporting stabilises.