About this replacement
Razer NAGA PRO / BASILISK ULTIMATE — 3.7V Li-Polymer Replacement Battery (CP-RC30D)
This is a 3.7V 650mAh Li-Polymer battery for the Razer NAGA PRO and BASILISK ULTIMATE wireless gaming mice. It replaces part number CP-RC30D and fits models RZ01-03420 and RZ01-034200100. Swap it in when the original cell no longer holds a charge or the mouse stops powering on entirely.
- NAGA PRO and BASILISK ULTIMATE compatibility: Both mice share the same internal battery bay geometry, connector pinout, and BMS handshake voltage. A single cell spec — 3.7V nominal, flat Li-Polymer form factor — covers both platforms without modification.
- Bench tested on actual hardware: We ran this cell through charge and discharge cycles on a NAGA PRO unit. The BMS accepted the cell cleanly, reported correct charge state in Razer Synapse, and no low-voltage cutoff errors were triggered during the session.
- Post-swap sensor calibration tip: After installing a new cell in a NAGA PRO, charge to full before first use — the onboard power management calibrates its gauge against a full-capacity reference. Skipping this step can cause Synapse to misread remaining charge by a wide margin for the first several cycles.
Why the NAGA PRO won't reconnect after a battery swap
When the cell drops to zero, the NAGA PRO's onboard firmware loses its stored pairing state. Re-inserting a charged battery restores power but doesn't automatically restore the USB receiver link. Unplug the HyperSpeed USB dongle, wait five seconds, and plug it back in. If the cursor still doesn't appear, hold the pairing button on the underside of the mouse for three seconds to force a re-pair cycle.
Mouse pointer stuttering or cutting out before the battery indicator hits empty
Li-Polymer cells develop high internal resistance as they age, causing voltage to sag under the load of the optical sensor and 2.4GHz transmitter firing simultaneously. The NAGA PRO interprets this momentary sag as a low-power event and drops its polling rate to compensate — which shows up as lag or stuttering. Synapse may still show 20–30% remaining when this starts. Replacing the cell resolves it; the symptom is a capacity and resistance issue, not a firmware one. A fresh CP-RC30D cell should hold above 3.5V under load during normal use.