I preside (advise) on a church committee to host our annual Nativities Display. We have a great sign in a great location near the road, but it’s fairly useless after dark because it has no light. In Minnesota at this time of year, dark starts at 4:30pm and continues until 7:30am the next morning. That means most people who work during the day never see it. It needed light!
The problem was, how to light a sign without a source of electricity nearby? A 200-foot extension cord would be possible, but it would have to be strung across the parking lot!
The solution was landscaping lighting, a marine battery, and a chain. We found 12 volt low voltage LED floodlights that only drew 7 watts. They provide a warm and surprisingly bright spot. We hooked two of them to an Energizer deep cycle marine battery, which looks like a car battery, but is made to discharge for long periods without recharge. The battery has 115 amp hours, so 7 watts x 2 will easily run for 6 hours of the dark Minnesota evening. Set it up each evening at 4:30, take it down at 10pm, then put it on the charger for the next day. A chain bolted to a battery box keeps it anchored to the sign. $150 of materials is much cheaper than laying an electric cable for this very seasonal use.
Now everyone can see the sign for the event. (Thanks to my friend Brent Spencer for advice and help on solving this puzzle.)