K-Touch Nibiru H1 Replacement Battery TBT9780A1 3.8V 2000mAh

K-Touch Nibiru H1 — 3.8V Li-Polymer Replacement Battery (TBT9780A1)

This is a 3.8V, 2000mAh Li-Polymer cell carrying OEM part number TBT9780A1. It fits the K-Touch Nibiru H1 and Nibiru H1C smartphones. It replaces the original battery when the existing cell has degraded, swells, or no longer holds a usable charge.

• Nibiru H1 and H1C compatibility: Both models share the same battery bay dimensions, connector pinout, and BMS handshake protocol. The TBT9780A1 cell measures 76.20 × 58.50 × 4.00mm — matching the original form factor so the back cover seats correctly without pressure on the cell.
• Bench tested on actual hardware: We ran this cell through a full charge and discharge cycle on Nibiru H1 hardware. The BMS accepted the cell without error flags, the charge IC stepped through trickle, CC, and CV phases normally, and the fuel gauge IC registered a clean state-of-charge reading at end of cycle.
• Fuel gauge recalibration on first use: After installation, disable fast charging for one complete discharge-to-charge cycle. The fuel gauge IC is still calibrated to the old cell's discharge curve. Running one slow cycle at standard current lets it map the new cell's characteristics before fast charge pushes higher current into an uncalibrated register.

Sudden shutdown at 20–30% on the Nibiru H1 after a cell swap

This is a voltage cliff issue, not a capacity fault. The new cell's internal impedance is slightly different from the degraded original, so the voltage curve under modem or display load drops faster than the fuel gauge IC expects. When voltage sags below the BMS cutoff threshold — typically around 3.2V under load — the phone shuts off even though the coulomb counter still shows charge remaining. One full discharge-charge cycle without fast charging closes the gap between the IC's learned curve and the new cell's actual behaviour. After that cycle, the shutdowns stop.

OS percentage jumping erratically after replacement

The Android fuel gauge IC on the Nibiru H1 stores a learned discharge model for the old cell in non-volatile memory. When a new cell goes in, the IC is still reading against that old model, so the reported percentage can jump 10–15 points as the phone tries to reconcile measured voltage against a mismatched curve. This is not a faulty cell. Let the phone discharge to automatic shutdown, then charge uninterrupted to 100% with the screen off. After that single full cycle, the coulomb counter resets its baseline to the new cell and percentage reporting stabilises.