There is a BranchCache registry key that controls whether or not a PC will share Cached content with its Peers when on Battery Power:
When a client is appointed as a Red Leader the ServePeersOnBatteryPower registry key is automatically set to 1 (Enabled)
While it is important for a Red Leader client to share cached content with its Peers, it may not be ideal for this to happen when that Red Leader is running low on battery power.
For this reason this function will only be enabled when the available Battery is greater than 33% of power remaining.
Upon demotion the key is returned to 0