Voltaic Magsafe 2 - VMAG2
MagSafe 2 Adapter - Female 5.5x2.5mm Adapter Laptop Battery to post-June-2012 MacBooks.
Charges MacBooks manufactured after June 2012. Confirm that the voltage output switch of the Voltaic V72 Laptop Battery (12V, 16V, or 19V) matches the voltage output of your AC wall charger as closely as possible. The MacBook Pro Retina may need to charge while asleep or turned off.