The Hardware Appliance comes with an external connector to plug-in a so-called battery adapter. Use this to buffer the internal HSM battery and extend its lifetime when the Hardware Appliance is turned off. This is for example helpful when a Hardware Appliance is operated as offline (root) CA:

Battery adapter

The adapter supports standard 6LR619V batteries:

Battery adapter with connected battery

Put the battery into the metal clip of the battery adapter. Use the connector on the back of the Hardware Appliance to connect it:

Hardware Appliance with connected battery adapter

After up to 10 minutes, the Hardware section of the Status page in WebConf will show the external battery - Ext. battery - with status and voltage:

WebConf: Battery status