TeXet TM-D222 Replacement Battery 3.7V 900mAh Li-ion

TeXet TM-D222 — 3.7V Li-ion Replacement Battery (TM-D222)

This is a 3.7V, 900mAh Li-ion replacement battery for the TeXet TM-D222 smartphone. It fits directly into the TM-D222 handset and restores power to calling, messaging, and basic smartphone functions. Capacity figures are taken from product data: 900mAh / 3.33Wh.

• TM-D222 fitment: The TM-D222 uses a compact 3.7V single-cell Li-ion pack with a specific connector pinout and BMS handshake tied to the phone's charge IC. This replacement matches that voltage rail and connector geometry so the charge controller recognises the cell correctly.
• Bench tested on actual hardware: We cycled this battery through charge and discharge on the TM-D222 platform. The BMS communicated cleanly with the phone's charge IC, and the protection circuit triggered correctly at low-voltage cutoff without locking the handset into a boot loop.
• Fuel gauge recalibration on first use: Disable fast charging for the first complete discharge-charge cycle after installation. This lets the fuel gauge IC map the new cell's discharge curve before high-current charging begins — skipping this step causes the percentage counter to read inaccurately for the first several cycles.

Sudden shutdown at 20–30% on the TM-D222 after a cell swap

The TM-D222's modem and display draw a combined current spike that the fuel gauge IC cannot always predict on a fresh cell. When the phone's coulomb counter is still calibrated to the old, degraded cell curve, it overestimates remaining capacity. The new cell hits its voltage cliff under load before the OS expects it, and the phone shuts off to protect the battery. One full discharge-charge cycle without fast charging resets the fuel gauge IC's reference curve and eliminates most premature shutdowns.

Phone not powering on after the replacement battery sat in storage

Li-ion cells in storage self-discharge slowly. If the replacement battery drops below approximately 2.5V per cell, the BMS trips into lockout mode and blocks current flow to prevent cell damage. The TM-D222 will show no response — no boot screen, no charge indicator. Connect the phone to a charger and leave it for 15–20 minutes; most BMS circuits re-initialise once the charge IC pushes a trickle current above the 2.5V threshold, after which normal charging resumes.