Highscreen Thor TBT9780A1 Replacement Battery 3.8V 2000mAh

Highscreen Thor / B2000A — 3.8V Li-Polymer Replacement Battery (TBT9780A1)

This is a 3.8V, 2000mAh Li-Polymer replacement battery for the Highscreen Thor and B2000A smartphones. It fits directly in place of the original TBT9780A1 cell. Use it when your existing battery no longer holds a charge through a normal day.

• Thor and B2000A compatibility: Both models share the same battery bay dimensions and BMS handshake protocol. The TBT9780A1 part number spans both, so the same cell works in either chassis without modification.
• Bench tested on actual hardware: We ran charge and discharge cycles on this cell and confirmed the BMS communicated correctly with the phone's fuel gauge IC. Cell voltage held stable across load steps, and the protection circuit tripped at the correct cutoff threshold.
• Fuel gauge recalibration on first use: On first use after installation, disable fast charging and run one full discharge-to-charge cycle at standard current. This gives the fuel gauge IC a clean reference curve for the new cell before high-current charging is applied to an uncalibrated pack.

Sudden shutdown at 20–30% on the Highscreen Thor after a cell swap

This is a voltage cliff issue, not a capacity fault. Under peak load — modem transmission, screen brightness spike, or a GPS fix — the new cell momentarily drops below the SoC threshold the phone uses to trigger an emergency shutdown. The fuel gauge IC is still reading from the old cell's discharge curve, so the percentage shown is inaccurate. One full discharge-charge cycle at standard rate re-anchors the coulomb counter to the actual cell chemistry, and the shutdowns stop.

Highscreen Thor not powering on after the replacement battery sat in storage

Li-Polymer cells in storage self-discharge over time. If the cell drops below approximately 2.5V, the BMS enters a lockout state to prevent damage and the phone will not respond to a power press. Connect the phone to a wall charger — not a PC USB port — and leave it untouched for 15–20 minutes. The charger's trickle-charge current will bring the cell above the BMS re-enable threshold, after which normal charging resumes. If the charge LED does not activate within 30 minutes, the cell has likely dropped below the recovery floor.