The 12 volt AGM is the 12 volt battery in the back under the hatch floor. The APM is the Auxiliary Power Module. It takes the place of the alternator in an ICE car. There is NO alternator in a Volt.Thanks. How can I locate the 12volt AGM and it's plugs or cables? Is it the black negative cable on the battery terminal? Also is the AGM different from the APM?