Motorola RAZR 50d 5G Compatible Battery QR31 3.88V 2850mAh

Motorola RAZR 50d 5G 2024 — 3.88V Li-Polymer Replacement Battery (QR31)

This is a 3.88V, 2850mAh Li-Polymer replacement battery for the Motorola RAZR 50d 5G 2024, also sold as the Razr 2024 5G (XT2453-1, XT2453-2). It replaces the original QR31 cell and restores power to the processor, display, and wireless radios. Fit the replacement when the original cell no longer holds charge or shuts down unexpectedly under load.

• XT2453-1 and XT2453-2 compatibility: Both hardware revisions share the same QR31 cell format, voltage rail, and BMS handshake. The connector and cell geometry are identical across all listed XT2453 variants, so one replacement covers the full production run.
• Bench tested on actual hardware: We cycled this cell through charge and discharge on a Motorola RAZR 50d 5G unit. The BMS accepted the cell without fault codes, and the charge IC transitioned through trickle, constant-current, and constant-voltage phases normally.
• Fuel gauge recalibration after installation: On first use after fitting, disable fast charging and run one complete discharge-to-charge cycle at standard current. This lets the fuel gauge IC map the new cell's discharge curve before high-current charging pushes current into an uncalibrated state.

Sudden shutdown at 20–30% on the replacement QR31 cell

This happens because the fuel gauge IC is still calibrated to the old cell's voltage-to-capacity curve. The RAZR 50d's modem and display pull sharp current spikes, and if the gauge misreads state-of-charge, the device hits the low-voltage cutoff before the percentage reaches zero. The fix is one full discharge — run the phone to automatic shutdown, then charge uninterrupted to 100%. After that cycle, the coulomb counter resets against the new cell and the percentage readings stabilise.

USB-PD fast charge not accepted on the first cycle after fitting

Some QR31 replacements take one standard charge cycle before the charge IC negotiates fast-charge handshake protocols. On the first cycle, the device may draw at standard 5V rather than the higher voltage tiers. This is normal BMS behaviour on a cold cell with no prior charge history. Charge once at standard rate, disconnect fully, then reconnect — fast charge should negotiate correctly from the second cycle onward.