Gomadic High Capacity Rechargeable External Battery Pack suitable for the Nikon Coolpix A900
Amazon.com: Nikon COOLPIX A900 Digital Camera Battery Charger (110/220v with Car & EU adapters) - Replacement Charger for Nikon EN-EL12 Battery : Electronics
En-el12 Battery (2-pack) + Charger For Nikon Coolpix A900, A1000, W300, W300s, P340, B600, S9700, S9900, S9900s Digital Camera - Digital Batteries - AliExpress
Promaster ProMaster EN-EL12 Battery - Nikon Coolpix B600, A900, AW120, S9600 - ASAP Photo and Video