IBM N6210 RAID Controller Replacement Battery 7.2V 5200mAh

IBM N6210 — 7.2V Li-ion Replacement Battery

This 7.2V 5200mAh Li-ion battery is a direct cache backup replacement for the IBM N6210 RAID controller. It holds controller cache data during a power failure, preventing data corruption or loss on write-pending operations. Voltage and capacity match the N6210's backup power spec at 7.2V and 37.44Wh.

• N6210 cache backup role: The N6210 controller holds unwritten cache data in DRAM. This battery bridges power between mains failure and full system shutdown, giving the controller enough time to flush or preserve that data. Without a functional cell, the controller drops to write-through mode and cache acceleration stops.
• Bench tested on actual hardware: We ran charge and discharge cycles, confirmed BMS communication across the connector, and verified the cell voltage held within the N6210's expected acceptance window. The BMS handshake cleared without faults on our test unit.
• Post-installation learn cycle: After fitting this battery, initiate a learn cycle from the management interface — on ONTAP use system controller battery show to monitor status. The controller remains in write-through mode until the learn cycle completes and recalibrates the backup window estimate against the new cell capacity.

RAID controller staying in write-through mode after battery swap

Swapping the battery does not automatically trigger recalibration. The N6210 controller needs to complete a full learn cycle before it trusts the new cell and re-enables write-back caching. Until that cycle finishes, the controller reports an uncalibrated backup window and holds write-through as a safety measure. On ONTAP, track progress with system controller battery show — write-back resumes once the cycle status clears.

ONTAP showing a battery error days after installation

The N6210 does not run a battery assessment at boot — it runs on a scheduled timed interval. A battery fitted on Monday may not be assessed until the next scheduled cycle fires, which can be 24 to 72 hours later under normal load. If the learn cycle has not yet completed when that assessment runs, ONTAP logs a battery error even on a healthy new cell. Wait for the learn cycle to finish, then re-check with system controller battery show before treating the error as a hardware fault.