With an optional Backup Battery Unit (BBU) installed on an Intel® RAID controller, and a RAID controller firmware version lower than 1.19, an error message may be displayed during POST:
"BBU bad or missing".
This is a standard warning on older firmware versions, to indicate that the battery may be charging or defective.
This error message is most likely to occur when the battery has either been newly installed or was depleted by loss of mains power and is recharging.
This message will usually disappear after the charging time of 24-48 hours if the battery is good, but was recharging at the time of the error message.
If you see this error message for a longer period than 72 hours, please contact Intel Customer Support.
The error message has been changed in firmware 1.19 to reflect that the BBU may be charging, as follows: "Battery charging or defective".
The Battery Backup Unit may also go through a learning cycle sporadically. When the battery is being charged, it will compare the total amount of charge it received with the number (indicating the maximum charge) stored inside the battery to determine the percentage of charge it is holding. After certain uses and when the battery gets older, the total charge which the battery can hold will reduce, but the battery does not know this until the maximum charge number stored inside the battery is reset.
This reset is performed during the learning cycle of the battery. The learning cycle preserves battery life. During the learning cycle, the BBU will ignore any manual configuration settings, such as caching. This is by design. Should there be a power loss during the learning cycle, and data is cached, this data may be lost or corrupted, therefore all caching is disabled. Once the BBU learning cycle is complete, all manually configured caching options will be re-applied automatically.
This applies to: