Under lights - how'd they do that?

[Divot]

Last night I took the motorcycle to the Western Idaho Fair and arrived the same time as a HD and parked next to it.  It was daylight when we arrived.  When we left it was dark and when we got out to the parking lot the HD was sitting there fully illuminated with lights under the frame and engine compartment.  It looked like they were LED lights and they looked pretty cool.  The owner was nowhere in sight. 

Now, I know you could do this with lights that illuminate when the bike is running or the ignition is on by tapping into the running light circuit, but how the heck do you do this when the bike is just sitting there and avoid running down the battery?
I'm not sure I want to do this, but with all the chrome on a Valk it could be pretty impressive. 

[Thunderbolt]

He probably came by and turned them on when you weren't looking, but they draw a lot less current than incandescent bulbs.

[Mr.BubblesVRCCDS0008]

A buddy of mine has some on his bike that came with a remote control. He can turn them on/off from inside a building. If the sunlight was bright they may have been on and not noticeable until in got darker.

[roboto65]

I am sure somewhere they have 12V light sensors that detect when it get darks just like on your car that would turn them on at dark !!!

[Madmike]

you could turn them on with a photosensor...... same idea as the modulating headlights use only they allow  the light to come on in the daylight and to not modulate in dark so you would want the opposite ... no ida what this would cost but the technology exists... thinking aloud .... you may be able to adapt the photosensor from a yard light to control a relay that would switch the lights on when dark..... there are various low voltage protection devices available but have no experience with them.......

[Jack B]

I have some on my Valk. Last year I put it in a bike show and I had the LED's on for both days ( off at night ). When the show was over it started right up. They take very little power.

[PatrickDoss]

I know a guy with some LED's on one of his bikes.  He parked it in the storage garage without noticing they were on.  When he went back -- ONE WEEK LATER -- the bike started right up.

It doesn't take many LED's to light a bike chassis/engine up.  That few drawing so little power each takes a long time to kill a good battery.