I replaced a failed battery in a Perc 5/i. The original and replacements are the same DLU8735 model. I couldn't find any special battery replacement procedures in the manual, so I just turned the system off and swapped them. After installing the replacement battery, GetBbuStatus started showing the battery as missing. GetBbuCapacityInfo showed it as charging, so I though perhaps this needed to complete before the battery would be used. However, it is now 100% charged yet still reported as missing. I thought perhaps I need to force a learn cycle, but this completes instantly with no change in status. The system is out of warranty, so I can't call Dell. Any ideas for why this battery is seen yet not used?
lspci | grep RAID
02:0e.0 RAID bus controller: Dell PowerEdge Expandable RAID controller 5
MegaCli64 -AdpBbuCmd -BbuLearn -aALL
Adapter 0: BBU Learn Succeeded.
Exit Code: 0x00
MegaCli64 -AdpBbuCmd -GetBbuStatus -aALL
BBU status for Adapter: 0
BatteryType: No Battery
Battery State: Missing
Exit Code: 0x00
MegaCli64 -AdpBbuCmd -GetBbuCapacityInfo -aALL
BBU Capacity Info for Adapter: 0
Relative State of Charge: 100 %
Absolute State of charge: 100 %
Remaining Capacity: 1897 mAh
Full Charge Capacity: 1900 mAh
Run time to empty: Battery is not being charged.
Average time to empty: Battery is not being charged.
Estimated Time to full recharge: Battery is not being charged.
Cycle Count: 0
Max Error = 0 %
Remaining Capacity Alarm = 190 mAh
Remining Time Alarm = 10 Min
Exit Code: 0x00
MegaCli64 -AdpBbuCmd -GetBbuDesignInfo -aALL
BBU Design Info for Adapter: 0
Date of Manufacture: 11/15, 2007
Design Capacity: 1900 mAh
Design Voltage: 3700 mV
Specification Info: 49
Serial Number: 4471
Pack Stat Configuration: 0xe4bc
Manufacture Name: SANYO
Firmware Version :
Device Name: DLU8735
Device Chemistry: LION
Battery FRU: N/A
Transparent Learn = 0
App Data = 0
Exit Code: 0x00
MegaCli64 -AdpBbuCmd -GetBbuProperties -aALL
BBU Properties for Adapter: 0
Auto Learn Period: 90 Days
Next Learn time: Sat Jan 1 00:00:00 2000
Learn Delay Interval:0 Hours
Auto-Learn Mode: Enabled
Exit Code: 0x00
Sounds like you have a bad connection. Others have reported success after blowing out the RAID battery plug and socket with compressed air.
If that doesn't work, you will need to try replacing the PERC 5/i (which in early 2014 costs less than $20 in good used condition) and/or trying another battery.