HPE ProLiant ML30 Gen10 Plus Maintenance And Service Manual page 120

9. Remove the system battery:
a. Use a small flat-bladed, nonconductive tool to press the battery latch (callout 1).
b. Remove the system battery from the socket (callout 2).
10. Install the system battery:
a. With the side of the battery showing the "+" sign facing up, insert the battery into the socket (callout 1).
b. Press the system battery down until it clicks into place (callout 2).
HPE ProLiant ML30 Gen10 Plus Server Maintenance and Service Guide 120