Mini Coin Cell Battery Pack with On/Off Switch
Finally, a battery pack you can fit into the trunk of your car! This little coin cell battery pack uses the same batteries (CR2032) as our other pack, but the batteries are stacked so the overall size of the pack is smaller. Check out the photos showing the size compared to LEGO studs!
You can probably get away with running 8-10 lights off of this pack, but to get any decent runtime, you'll probably want to limit it to six.