Renishaw XR20-W Replacement Battery A-9920-0330 3.7V 1800mAh

RENISHAW XR20-W / XM-60 Series — 3.7V Li-Polymer Replacement Battery (A-9920-0330)

This is a 3.7V 1800mAh Li-Polymer battery built to the A-9920-0330 specification. It fits the XR20-W rotary axis calibrator, XR20, XM-60, and XM-600 multi-axis calibrators. Capacity is 6.66Wh — matched to the original pack rating, sourced from product data.

• XR20-W, XR20, XM-60, XM-600 compatibility: These four instruments share the same 3.7V power rail, identical connector pinout, and the same BMS handshake protocol — which is why a single pack covers the full range. The A-9920-0330 part number is common across all four, confirmed by Renishaw's own documentation.
• Bench tested on actual hardware: We ran this pack through a full charge-discharge cycle and monitored BMS behaviour across the probe initialisation current spike — the point where most low-capacity substitutes trip. The protection circuit held without cutoff, and the pack reached its rated capacity within the first full cycle.
• Post-install calibration cycle: After fitting this battery, run a full calibration sequence through the instrument menu before deploying to a measurement session. The XR20-W maps battery state during calibration — skipping this step causes premature low-battery warnings to appear during your first measurement run even when the pack is fully charged.

BMS lockout after the XR20-W sat unused in a carry case

Li-Polymer cells self-discharge at roughly 1–2% per month at room temperature. If the instrument sits unused for several months, the cell voltage can drop below the BMS's 3.0V recovery threshold — at which point the protection circuit locks out and the pack appears dead. Connecting the charger in this state often shows no charging activity because the BMS is blocking current input. To recover, connect to the Renishaw charger and leave it for 20–30 minutes without interruption — some chargers apply a low-current pre-charge pulse that brings the cell back above the recovery threshold before entering normal charge mode.

XR20-W shuts down during USB data transfer to PC

USB data transfer adds a combined load to the instrument — the processor, wireless module, and USB interface all draw simultaneously. On a worn or partially discharged pack, this combined draw causes a momentary voltage sag that dips below the BMS cutoff threshold, tripping a shutdown mid-transfer. The fix is to ensure the pack is charged above 3.6V before starting any transfer session. If the shutdown recurs on a new pack, check the USB cable — a high-resistance connection increases total draw and makes the sag worse.