Installed the GPS unit and connected it to "switched" power per instructions. GPS turns on when I turn the bike on but when I turn it off, the GPS stays on. Most Garmin units have a screen alert that states external power has been lost do you want it to stay on. I get no such message with the unit. Biggest fear is that it goes into "charging" mode and drains cycle battery when turned off leaving me with a dead RT. Any suggestions?