Each server contains a battery pack. The battery pack maintains the NVRAM contents when the server is not receiving power (due to a power failure or a short-term shut down). The battery pack is located behind the front bezel cover of the server, on the left-hand side. The battery pack is hot-swappable and can only be accessed after the front bezel has been removed.
Battery pack characteristics:
- Each server contains a single battery module. The module contains dual redundancy inside.
- The battery pack uses NiMH technology.
- A battery pack has a two year operational life. A timer starts when a server is booted for the first time, and the timer is manually restarted when a replacement batter pack is installed. After two years of operation, a log warning event is issued to warn the user that the battery pack should be replaced.
- The battery pack is periodically tested to ensure it is operational.
- A fully charged battery pack maintains the NVRAM contents for approximately 72 hours.
- When a new server is installed and powered on, the battery pack is not fully charged (it will not be at 100% capacity). After being powered on, the server performs tests and starts a conditioning cycle, which may take up to 24 hours to complete. During the conditioning cycle, the full NVRAM content backup protection time of 72 hours cannot be guaranteed.
- A replacement battery pack may not be fully charged (it may not be at 100% capacity) when it is installed. After a new battery pack is installed, the server performs tests and starts a conditioning cycle, which may take up to 24 hours. During the conditioning cycle, the full NVRAM content backup protection time of 72 hours cannot be guaranteed.
- If a server is left powered off, the battery will discharge slowly. This means that, when the server is powered up, the battery will take up to a certain number of hours to reach full capacity and the time depends upon whether a conditioning cycle is started. The scenarios are:
- 24 hours if a conditioning cycle is started
- 3 hours if a conditioning cycle is not started
During the time it takes for the battery pack to become fully charged, the full 72 hours of NVRAM content protection cannot be guaranteed. The actual amount of time that the NVRAM content is protected depends on the charge level of the battery pack.
- A battery pack may become fully discharged because of improper shutdown, a power outage that lasts longer than 72 hours, or if a server is left unpowered for a long period of time.
If the battery pack is fully discharged:
- The battery pack may permanently lose some long term capacity.
- Assuming a battery conditioning cycle is not started, a fully discharged battery pack takes up to 3 hours before it is fully charged. If a battery conditioning cycle is started, a fully discharged battery pack takes up to 24 hours before it is fully charged.
- A battery conditioning cycle is started if the server is powered down for longer than three months.
- A battery pack may be stored outside of the server for up to one year before it must be charged and/or conditioned. After one year without being charged and possibly conditioned, the battery capacity may be permanently reduced.
If you store battery packs for more than one year, contact your representative to find out about conditioning your battery packs.
When preparing a server for shipment, if the NVRAM is still being backed up by battery (indicated by the flashing NVRAM LED), the battery can be manually isolated using the reset button. See Reset button (RST) for the location of the reset button.
When preparing a server for shipment or if it will be powered down for any length of time, it is important that the server has been shut down correctly before powering-off. Otherwise, if the server is improperly shut down, the batteries supplying the NVRAM will become fully discharged. This also occurs if the system is powered down for too long without following the proper shutdown procedure.NoteIf the batteries become fully discharged, or the system is to be powered down for an extended period, see Powering down the server. Contact customer support for information about recharging batteries.
To replace the NVRAM battery backup pack, see Replacing the NVRAM backup battery pack.