Hey, great questions. 1. The graph and our predictions are all theoretical. We are working to finalize our charging system now and will be doing some test in the coming weeks, to get some real world numbers. Also, the 50% discharge is relative BS. You can discharge a deepcycle lead acid 100% and still charge it back up, it just reduces the life span significantly. But, for us, Even if we had to replace our batteries every year, that's still only $400 a year. WAY cheaper than diesel fuel. So we feel like its still a win. 2. We've thought about using the 18650's. But, 1. The labor to put them together is intensive to say the least. 2. they are actually no cheaper than normal Lithiums, unless you can find then "used" which is vary difficult without the right connections. There is a company that sells used Tesla batteries from their cars. We're looking into using them. They're about 3kw and 50V so 2 would work for us just nicely. 3. So far solar has really been more than enough. We sized our battery bank to be recharged from 100% discharge in one sunny day. So far, tha t has been the case. Wind is also a relatively low wattage charging source. Also, noisy. We are however designing and will soon be testing regeneration from the prop, which in theory will be a great, reliable power source while sailing. Hope that helps answer you questions.
Following this aspect of your project, very interesting. The gas outboard on my Precision 23 crapped out several months ago and I haven't replaced it in part because I tried using the smallest Minn-Kota motor and it got us in and out of the marina just fine as long as the wind was light or favorable. If the wind was too strong, we could sail out and in. This has also made us better sailors I feel. I definitely have to think much further ahead with electric, at least this small, not having the torque/power that the 9.9 Johnson did. But it's so quiet, it has really got me thinking about the possibilities. If necessary in a pinch, have you researched the efficiency of keeping your battery bank charged with a gennie so as to keep motoring if you had too for whatever reason? Thanks: Derek email@example.com