About this replacement
Hitachi VSP G1000 Series — 10.8V Ni-MH Replacement Battery (3289081-A)
This is a 10.8V, 4500mAh Ni-MH battery for the Hitachi VSP G-series RAID controller cache backup circuit. It fits the VSP G1000, G800, G600, and G400 controllers. When main power drops, this battery holds cached write data long enough for the controller to flush it safely to disk.
- VSP G400 / G600 / G800 / G1000 shared battery rail: These four controller generations share the same 10.8V three-cell Ni-MH backup circuit, the same physical connector, and the same BMS handshake protocol. One battery SKU covers the full G-series platform because the backup window calculation and charge termination logic are identical across all four.
- Bench tested on actual hardware: We ran full charge-discharge cycles and confirmed BMS charge termination via delta-V detection at the expected endpoint. The cell pack held 4500mAh across three consecutive cycles with no thermal event and normal trickle float behaviour.
- Post-swap learn cycle on VSP controllers: After installing this battery, trigger a learn cycle from the Hitachi Storage Navigator or RAID management interface. The controller uses the learn cycle to measure the new cell's actual backup window — it will stay in write-through mode until that calibration completes, which typically takes 24–72 hours under normal array load.
VSP G1000 controller stuck in write-through mode after battery swap
Write-through mode activates any time the controller cannot verify a safe backup window on the installed battery. Swapping the cell does not automatically reset this — the controller must complete a full learn cycle to recalibrate the backup window estimate against the new Ni-MH cell's actual capacity. Until the learn cycle finishes, the controller deliberately disables write-back caching to protect data. Initiate the learn cycle manually via Storage Navigator or run raidcom get battery to check current status and confirm the cycle is progressing.
Management console showing battery fault error days after a confirmed good installation
This catches many admins off guard — the battery was installed and appeared fine at boot, then a fault flag appeared 48–72 hours later. The VSP controller runs its formal battery self-assessment on a timed interval, not at power-on, so a degraded or not-yet-calibrated cell can pass initial boot checks and fail the scheduled assessment later. If the learn cycle had not been explicitly initiated after the swap, the assessment runs against an uncalibrated backup window and returns a fault. Start the learn cycle from Storage Navigator and allow the full cycle to complete before clearing the fault flag — the voltage floor the controller checks against is 9.6V under load.