The short story is that I think my GPS (Garmin Nuvi 500) is running down my battery while the bike is parked even though it is turned off. The Nuvi has a rechargeable battery, so there's always some draw. But it seems like it is running down my almost new Odyssey battery in about 2 days. I have the 12V power cord running down under the tank to the underseat compartment where it plugs into a 12V outlet directly wired to the battery.
It's not definitive yet (I haven't tested the actual current draw), but it seems to be the culprit. Anybody know the power draw of the unit or the cable itself (which steps down the voltage to 4v)?
I suppose I could always just leave it unplugged when it's parked, but that seems like it shouldn't be necessary.