Regen under sail does sound good, but the only real success stories have come from multihulls and large boats. This is because of their extra speed capabilities. I don't know of any verified claims of generating more than 100W (2A @ 48V) at 5kts or less. Since the act of regen slows the boat down, a displacement type 30' boat will have to be pushed pretty hard to stay above 5kts and even then, the energy collected won't put very much back. Here's a scenario, you head out of your slip and spend 15 minutes at 4-5kts getting away to clear water. If you've averaged 3000W, you've used 750Wh. Averaging 5kts under sail, you're generating 100W. 4 hours later, you've put back a little more than 1/2 the energy that you used up front. Even running slower under power, like 1500W, for every 4 minutes under power, you need an hour of sailing at 5kts to break even. Of course, like you said, many drive systems already include this capability, so any collected energy is essentially "free".
Wind generation also seems to work better in theory than in practice in many areas. The common Generators like Air-X take a noticable amount of wind before they generate anything. According to the manufacturer, an average of 10kts of wind puts out 50W or only 1200Wh over a 24 hour period of non-stop wind. At 20kts of wind, it's still only around 200W of output. Around SoCal, the winds are rarely above 15kts. Spending another $1000 for this kind of limited charging capability is a tough sell to me.
Many people, including me, think that solar panels are the most effective renewable energy source, IF you have a decent place to mounts them. They're quiet and have no moving parts. Finding the mounting space for decent size panels without transient shadows can be problematic on some boats, including mine. If solidly mounted (non-tracking), panels will generate about 4-6 hours times their rating on a sunny day. For example, a 150W panel will typically generate 600-900Wh per day, but it will do so pretty consistantly.
Fair winds,
Eric
Marina del Rey, CA
--- In electricboats@yahoogroups.com, "John Green" <v_2jgree@...> wrote:
>
> Dan, I think you have it nailed, I am actually getting way ahead of myself!
> And, as a current non-sailor, I have no idea of my ultimate mission, as it will develop over time....
> Although aware of it, I hadn't even given thought to charging by generating while under sail! That has got to be a great way to go. Again, once I actually get the darn boat moving, I can fiddle with that, too. Might be a quieter option than wind power. And once set up, the price is right!....
>
> Thanks,
> John
>
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