Details:
Probably the easiest way to connect our DC LEDs to power is using a 9V battery, with these nice long battery snaps. As you can see from this photo, the battery snap is designed to snap onto the leads on the terminal end of any standard 9V battery.
These battery straps have two leads, a red "positive" wire and a black "negative" wire. Each of our pre-wired LEDs also comes with a red positive wire and a black negative wire.
All you need to do is twist all of the red wires from the LED kit together with the red wire from the battery strap. Protect this connection with some tape or shrink tube. For larger numbers of wires, a bit of solder added to this joint is a good idea.
Next, twist all of the black wires from the LED kit with the black wire coming from the battery strap, protecting the connection with electrical tape or shrink tube.