NetApp 271-00024 RAID Controller Replacement Battery 7.2V 2600mAh

NetApp 271-00024 — 7.2V Li-ion Replacement Battery

This is a 7.2V, 2600mAh Li-ion replacement battery for NetApp RAID controller backup power units. It supplies emergency power to the controller's write cache during an unexpected power loss, allowing buffered data to flush safely to disk. OEM part numbers 271-00024, 271-00024+C0, and ES3242 all cross to this cell.

• RAID controller cache backup role: These controllers hold write cache in volatile memory. The battery bridges power loss events long enough for the controller to destage that cache to non-volatile storage. Voltage, cell format, and BMS handshake must match the original — a mismatch causes the controller to lock in write-through mode permanently.
• Bench tested on actual hardware: We cycled this cell under simulated cache-backup discharge loads and confirmed the BMS communicates charge state correctly to the controller management interface. The cell reached rated capacity within two full learn cycles.
• Learn cycle after installation: After fitting this battery, initiate the learn cycle from your controller interface — ONTAP: system controller battery show; Broadcom/LSI: StorCLI /cx bbu show. The controller stays in write-through mode until the learn cycle completes and the backup window is recalibrated against the new cell's actual capacity.

RAID controller staying in write-through mode after battery swap

Write-through mode is not a fault — it is the controller's default when it cannot confirm the battery can sustain the backup window. After a battery swap, the controller has no learned data for the new cell, so it holds in write-through until a full learn cycle recalibrates the backup window estimate. On ONTAP systems, run system controller battery show to check learn cycle status. The controller returns to write-back mode automatically once the cycle completes, typically within 24–72 hours under normal array load.

Management console showing a battery error days after installation

NetApp controllers run their battery assessment on a timed schedule, not at boot — so an error can surface 24–72 hours after a swap even when the cell is functioning correctly. If the learn cycle has not finished, the controller reports an indeterminate state as an error. Check learn cycle progress first: a completed cycle with a voltage reading above 7.0V rules out a cell fault. If the error persists after cycle completion, reseat the battery connector and re-run system controller battery show to force a fresh status poll.