You think you folks have problems, try battery management on a kayak. Some of us are running sonar, lights, and even trolling motors and we're counting every amp and pound. There is light at the end of the tunnel in the form of LifePO4 technology, the latest in lithium advancement. LifePO4 is a chemically more stable, much lighter, and constant power producer and unlike traditional lead acid batteries, breaks the 50% capacity boundary. They also provide thousands of recharge cycles giving you upwards of a ten year life span. The only drawback to LifePO4 is the COST! A LifePO4 battery similar in size to the battery you are now using in that 21' bass boat can set you back $800+. As with any new technology, I believe the cost will eventually go down. (In my lifetime?) These LifePO4 batteries are built using individual cells that are available to the consumer and depending on the source, are as cheap as $20 each. I've been working with a couple of friends in using these individual 3.2V cells to make a battery pack, complete with BMS (battery management system) that I hope will come in under 15 pounds. So far, the high amp draw over time test is not creating any heat issues, so maybe...