Patch 1.71 says that standby mode actually recharges controllers. But I am not seeing any difference in the battery level of my controller after leaving my console on standby for an hour or more with my controller connected... Is this just a case of Sony's wonderful QA? Or is there some other setting that needs to be enabled.
From the main menu bar go to:
-> Settings -> Power Save Settings -> Set Functions Available in Standby Mode -> Check the checkbox for Supply Power from USB Ports
Your controllers should now charge in Standby mode.