Battery powered Christmas decorations are a source of distress in the Middleton household. My Mum bought a nice string of lights with bows, and 3 AA batteries. No sooner had she adorned the windowsill than my Dad was working out the current draw and subsequent amount of time to drain the batteries. While this is the least Christmassy train of thought imaginable, it did present a handy use for all those old 5V Nokia chargers we have lying around.
So we chopped off the end of the wire going into the battery holder, and soldered it onto the 5V charger. The LEDs were emitting light as powerful as the sun so we hastily added a resistor.
Everyone has at least 4 old Nokia chargers in their 'things' drawer so I recommend soldering battery powered stuff to them at any opportunity.
1. Chop off the wires before the pesky battery pack (save the battery pack, put in 'useful things' drawer)
2. Chop off and strip the Nokia wire. Solder the lights to the charger wires with a resistor in between
3. Try to arrange them so they look a bit nicer
4. Wrap them up to disguise your awful soldering skills
5. Proudly display
I should add that it's not actually necessary to have an enormous 4-way spool adapter to connect these. If interior design is your priority you can probably hide the plug.