The BBU (Battery Backup Unit) is a CRU (Customer Replaceable Unit) in the VNX series of arrays. Included in the list is the VNX5200, VNX5400, VNX5600, and VNX5800 units that have the CRU part numbers 078-000-132-00 and 078-000-092-07.

Located on the back of the VNX2 array’s DPE is where you can find the access to the BBUs. They have orange release tabs which you press inward as depicted in the image below:

After removing the bad BBU unit, insert the new unit with the white label facing up. Slide in until the unit locks into place. See image below:

To replace a Battery Backup Unit (BBU) in an EMC VNX5200, VNX5400, VNX5600 and VNX5800 you can perform the following steps:

1. Identify the faulty BBU (A or B listed in Unisphere)
2. Remove the BBU from the base module
3. Push the orange release tab on the supply to the right while holding the BBU’s handle
4. Place the BBU on a clean, static-free surface after removing it from the base module
5. To install the replacement BBU, hold it with the white label facing up
6. Align the BBU with the slot in the base assembly
7. Push the BBU into the slot until it clicks into place  

After replacing the BBU, you can check the System Health page and Unisphere to ensure the new part is marked with an OK status icon.