Netgear C7100V (AC1900) battery backkup

I recently bought a battery pack to back up my device during power outages.  I had not bought one when I purchased the original device.  The C7100V RECHARGEABLE BATTERY PACK WARNINGS AND SAFETY information included with the battery pack makes a reference to charging ("Charge the battery pack in a room-temperature environment...") but does not specify a charger.  Does this pack charge itself when installed in the Router or do I need to purchase a separate charger?  Should the battery just be installed and left in the device as the short INSTALL THE BATTERY directions imply?  Is there any way to ask this question to a Netgear support tech other than by snail mail?  It should be a simple, quick question, but has already taken up way too much time.