Just wanted to chime in regarding new batteries being reported "missing" by the RAID controller.  I recently purchased 8 new batteries to replace in my aging fleet of PE2950's with PERC 6i.  Prior to deploying in production, I wanted to test the batteries and give them a bit of a charge on the test bench 2950.  I would power off the system, swap in the new battery, power up, and get the battery "missing" error.   No amount of time with the system turned on would get the battery to a "charging" state. I was in complete disbelief that 6 out of the 8 batteries were bad.  I was about to return them to the vendor when I discovered the system power supply cords must be completely disconnected from wall power, and the motherboard completely drained of residual power  before swapping the battery!!   Once I performed this step before each battery swap, all batteries tested good and are charging !! 
Hi All,   I had a failed battery in our PE2950. I ordered one off of Ebay new and replaced it last week. I then went into OpenManage and ran the learn cycle. After a week I went in and now it is showing as non-critical. I will be going to my DC next week to troubleshoot but I assume I can only plug the wire into the battery one way, correct? Does this appear to be a faulty battery?     Controller PERC 5/i Integrated (Slot Embedded)ID                  : 0Status              : Non-CriticalName                : Battery 0State               : MissingRecharge Count      : Not ApplicableMax Recharge Count  : Not ApplicableLearn State         : ActiveNext Learn Time     : 0 hoursMaximum Learn Delay : 7 days 0 hours
Failed PERC 5i battery replaced now shows as missing