Would it be safe to say that connecting 3 individual LED's to one battery will reduce the battery life to a third of what it would normally be with just one battery?

I'm using the throwies minus the magnet as part of a table centerpiece at my wedding reception, and am gonna use them inside of our chinese lanterns to light them up. The only problem, one LED doesn't light up the lantern well enough. I was thinking sticking 2 or 3 of the 10 mm ultra bright LED's connected to one battery...but wasn't certain how long it would last. Of course I would have to hang the lanterns up well ahead of the reception so I would need a good 6+ hours. Perhaps it would be safer to just use one battery per LED.

Any thoughts?

I would assume that barring horrible batteries, it should still last longer than 6 hours... But as long as your wedding isn't TOO soon, you could always try one and see.

You could also make some sort of switch, if you're still concerned. Even just running around the tables taping one leg to the battery at the last minute would be an option (albeit a flimsy one) if you're still worried about time.

You can do this, but the lifetime of the batteries may be less than just one third, because the batteries don't like to source that much current at a time. Still, 1/3 of two weeks is longer than 6 hours.

A second strategy would be to use more than one battery + LED per lantern, or to use a "real" battery-- two AAA's will run several white LEDs very bright for quite a while. (Three AAA's, even brighter, but you'll need a resistor in series with each LED.)