I'm discovering my Odyssey Extreme batteries are dropping voltage although the reserves are very potent. I'm seeing 11.7-11.5 VDC on my plotter screens. Very hot final charge I start with 12.50+VDC but even with a PC1500 and only 3 - 9in screens running along with a plain Panoptix transducer after 3 hours of fishing I'm down to 11.7VDC. I'm thinking a small dedicated lithium for just the Panoptix transducer and a larger lithium for the rest. Space is a problem so I have to engineer something. Does Impulse Lithium have a program for CDC members?