How do I maximize PW2 battery life?

How do I maximize PW2 battery life?

Trying to find resources to help answer my question. Posting here to double check.

1) Looked for the answer on official Tesla documents / manuals. No luck
2) Tried to sift through the forum here. No luck.
3) Called customer support and got a couple of different (and contradictory) answers. Which tells me they don't have a script to use.

If my goal of the PW2 was to make it last - keep its maximum capacity-- for long as possible, do I just keep it in Backup-only mode all the time?