That is the error I used to get, "low voltage...." It might have something to do with your battery, but it might not.
Try this, make sure the car is in test mode (fans and pump cycle intermittently). If your car isn't in test mode, you didn't make the proper connections under the dash. Now, after you select a basemap, the AP will prompt you to turn the ignition off and back on. When you turn the ignition back on does your car stay in test mode? If it doesn't, skip the ignition off/on step, and just press "ok" while your car is in test mode. Some of us had this problem awhile back and this worked for us.