Ah woops...
Hi Eric,
There's few other factors working against us harvesting as much solar power as might come from stationary panels...Apart from what you mention there's also the way I arranged the panels around the dinghy. The two on the bow were tilted up a little at the bow, more or less following the sheer of the dinghy. This should be ok because we were going south with the sun in the north.The panels on the sides were angled inwards, just the way the jury rigged attachment system worked out. So the panels are all on the same plane, and I'm expecting that would lessen their effectiveness.Because they were mounted low, if I sat on the seat I would shade the forward panels. And even though sitting down in the zodiac's belly was ok, after an hour or two I ran out of different ways to sit comfortably so resorted to sitting on the seat for a while every now and then, and noticed when I did so that the watts coming from the battery would increase (ie less from the sun). So we lost a bit that way.And the other thing was most of the morning up till around 11 was overcast and so less than optimum.But all things considered I think we had a good harvest.One of the yachties around here made the comment that if your boat was sinking (the big boat that is) it could be good to take a solar panel and Torqeedo with you when you jump into the rubber dinghy/life raft. Then, even though it might take a while, you could eventually get home.And I'm impressed with your swimming speed :)CheersChrisOn 07/08/2011, at 7:57 AM, Eric wrote:Hi Chris,
What a great experiment! I appreciate your perseverence to take the time to cover a long distance at a slow speed. It's interesting that the 160W (4 x 40W) of solar panels would just cover the 80W motor load on average during the day.
Doing a bit of the math, you used about 720Wh (80W x 9 hours), let round up to 800 for the "fast finish". You finished with about 70Wh in the battery so you used 330Wh from there. The remaining 470Wh would have come frm the panels. I've heard that a stationary panle will collect 4 to 6 times its rated capacity in Wh over the course of a day, depending on latitude and time of year. With 160W of rating, 480Wh would be a factor of three. This seems reasonable because of the moving boat and the fact that you didn't stay out for every trace of your winter daylight.
And I can really appreciate your comment about 1.5kts is not exactly a speed, I can swim 3000m in an hour (1.6kts), but not for 8 hours straight.
Congrats for a good day on the water.
Fair winds,
Eric
Marina del Rey, CA
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