About this replacement
Corsair K57 RGB Wireless Gaming Keyboard — 3.7V Li-ion Replacement Battery (RDJ15)
This is a 3.7V, 3400mAh Li-ion battery that replaces the internal rechargeable cell in the Corsair K57 and K57 RGB Wireless Gaming Keyboard. It restores wireless operation when the original battery no longer holds a charge. Capacity is rated at 12.58Wh and dimensions are 38.20 × 18.60 × 18.60mm.
- K57 and K57 RGB platform fit: Both K57 variants share the same battery bay geometry, connector pinout, and BMS communication protocol — which is why a single cell covers the full platform.
- Bench tested on actual hardware: We cycled this cell through full charge and discharge on the K57 RGB. The BMS accepted the cell without fault flags, RGB polling remained stable, and the wireless receiver held its 2.4GHz link throughout.
- RGB load management on the K57: Per-key RGB lighting draws significantly more current than standard wireless keyboards. Keep lighting profiles at mid-brightness or lower during wireless use — full-brightness animations are the single largest drain on this cell.
Pairing lost after battery swap on the K57
A full power loss during battery removal can wipe the keyboard's stored pairing state. The K57 stores its 2.4GHz link to the USB receiver in volatile memory that clears when voltage drops to zero. After fitting the new cell, hold the wireless connect button on the keyboard until the indicator flashes, then replug the USB receiver. This forces a fresh handshake and restores normal wireless operation.
K57 RGB not powering on after sitting unused for several months
Li-ion cells that sit discharged below roughly 2.5V enter a deep-discharge state where the BMS blocks normal charging as a protection measure. Plug the keyboard in via USB-C and leave it connected for at least 30–45 minutes before pressing the power button — the charger needs time to trickle the cell back above the BMS re-enable threshold. If the keyboard still shows no activity after that period, check that the cable is delivering power to the port and not just a data-only connection.