Aston Martin DB11 Owner's Handbook Manual page 242

Battery Conditioner
(Optional)
Caution: Do not attempt to start the vehicle with a battery
conditioner connected to the mains supply.
The Aston Martin battery conditioner is suitable for use on all
types of 12 volt AGM and lead acid batteries.
If this vehicle is not going to be used for a period of time, and
mains power is available, use a battery conditioner to maintain
the battery charge level. When connected the battery
conditioner will maintain a small trickle charge to keep the
battery in a fully charged state. A battery conditioner is designed
for conditioning of partially or fully charged batteries. It will not
effectively charge a discharged battery.
12.40
Maintenance and Technical Data
The battery conditioner uses a magnetic disc to attach to the
charger socket (A). To connect the battery conditioner, open the
deck lid and attach the charger plug onto the charger socket. The
deck lid can then be closed and locked with the charger
connected.
For further safety information and operating instructions, refer
to the instructions supplied with the battery conditioner.