Sun Blade Raid Card 5 371-2658 Replacement Battery 3.7V 1100mAh

Sun Blade RAID Card 5 — 3.7V Li-ion Replacement Battery (371-2658)

This 3.7V 1100mAh (4.07Wh) Li-ion cell replaces the backup cache battery on the Sun Blade RAID Card 5, Blade X6250, and Xeon E5450 controller platforms. It maintains volatile write-cache memory during a power loss event, allowing cached writes to complete safely to disk. Without a functional backup cell, the controller drops to write-through mode and cache protection is lost.

• Blade RAID Card 5 / X6250 compatibility: These platforms share the same battery connector, voltage rail, and BMS handshake protocol, all referencing OEM part 371-2658 (cross-referenced as SQU-711 and 916C5940F). The controller's BMS communicates directly with the cell over a dedicated SMBus line to track state-of-charge and backup window estimates.
• Bench tested on actual hardware: We cycled this cell through the RAID controller's learn sequence and confirmed the BMS completed a full charge-to-discharge calibration pass. The controller transitioned from write-through to write-back mode once the backup window estimate exceeded the controller's minimum threshold.
• Post-swap learn cycle initiation: After fitting this cell, run the battery learn cycle from the controller's management interface — on ONTAP use system controller battery show; on Broadcom/LSI use StorCLI /cx bbu show. The controller will remain in write-through mode until the learn cycle completes and the new cell's backup window is recalibrated. This typically takes 24–72 hours under normal server load.

RAID controller staying in write-through mode after battery swap

Swapping the physical cell does not automatically trigger recalibration. The controller's BMS must complete a full learn cycle — a controlled charge and discharge pass — before it will calculate a valid backup window for the new cell. Until that window meets the controller's minimum threshold (typically 72 seconds of hold time at operating voltage), write-back mode stays locked out. Manually trigger the learn cycle via StorCLI or ONTAP rather than waiting for the next scheduled assessment.

Management console showing battery error days after the swap

The controller does not re-assess battery health at boot — it runs a scheduled assessment on a timed interval, often 24 to 90 days depending on firmware. If the console reports a battery error shortly after installation, that alert is likely carried over from the degraded original cell and has not yet been cleared by a fresh assessment cycle. Force a new assessment via StorCLI /cx bbu startlearning or the equivalent ONTAP command. Once the learn cycle completes and the BMS logs a valid backup window, the error clears automatically.