I wanted an inexpensive and decent power supply for my kayak that would provide enough power for my fishfinder as well as a few lights for night fishing. I have the fishfinder installed, but am still deciding about what lighting I want to install. Anyway, I decided on two 6 V, 7 Ahr alarm/safety batteries that are available from Home Depot. These are sealed gel batteries that are fully rechargeable and provide a consistent power output for the length of their discharge life. Two can easily be connected in series to provide 12 V. Now, how would I securely fasten the batteries to the kayak and connect safely to them? I came up with this idea: The battery box is an inexpensive container that you can purchase at Wal-Mart. It is shown here strapped to the kayak using a 1/4" nylon cord tied around the scupper "pillars." The batteries are tucked inside, surrounded with a foam cushion that I cut in layers to fit. Notice how I cut through the container lid to connect the batteries in series. The fishfinder transducer is mounted directly in front, firmly to the hull using marine goop in a 3" PVC protective shielding. Here you can see the terminal strip attached to the front, the power switch on the side (to prevent charger power from reaching the fishfinder), the 1 A fuse, and charger plug (on right top). I modified a 12 V battery charger to have a polarized connecting end that will plug directly into the charger plug on the battery box for a quick recharge. Notice that the terminal strip provides enough connectors that I can easily add a lighting circuit separate from the fishfinder circuit. This way, I can either add another in-line fuse of a different value, or skip the fuse for the lighting circuit altogether. This view provides perspective on the location of the battery box in the hatch. Hatch still provide plenty of room for storing cart wheels, waders, and other cargo.