This seems like a fun weekend project with to teach kids about how batteries work in a hands-on fashion. Instructables user egbertfitzwilly has published a how-to for a simple aluminum can, saltwater, and charcoal battery.  

Becky Stern

Becky Stern

Becky Stern ( is a DIY guru and director of wearable electronics at Adafruit. She publishes a new project video every week and hosts a live show on YouTube. Formerly Becky was Senior Video Producer for MAKE. Becky lives in Brooklyn, NY and belongs to art groups Free Art & Technology (“release early, often, and with rap music”) and Madagascar Institute (“fear is never boring”).

  • Walt

    OR – could be a life saver if your RV meth lab runs out of battery in the middle of the wilderness.