29. July 2010 by gmoney.

Sean’s recent speed trials have us thinking the motors will run more efficiently with an 8 volt system.  Since this won’t be an issue with the rest of the electronics (we already use a voltage regulator), and not a problem for the PV system (we can charge at 10.8 volts with 3 parallel sets of 3 panels in series), the decision is made.   The keel will now contain 5 lead acid, 8 volt, 3.2 AH, batteries from our friends at batterydirect.com

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25. June 2009 by Sean.

Here’s a cool project using solar, boats and radio control.  Most impressive is the robot voice over techno music.  By the end you’ll be really cranked up to build your own solar boat out of household scraps.

http://www.youtube.com/watch?v=ZmDqklgQvj0

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27. May 2009 by gmoney.

We are using 9 Pitsco “Ray Catcher” Solar Panel’s:

http://shop.pitsco.com/store/detail.aspx?ID=2550&bhcp=1

Each panel is rated at just over 3 watts (2.8 volts x 1,100mA), however our testing found each panel would output 3.0 to 3.25 volts in full sun (in February no less).   Preliminary sample circuit tests also showed that 2 panels in series were sufficent to charge up our 6V batteries.

The circuit we will assemble for the proto-boat tests will be 3 circuits with 2-panels in series and 1 circuit with 3-panels in series.  Those 4 circuits will then be connected in parallel.

There will be no diodes for 2 reasons: 1) we can’t afford the voltage drop, and 2) backwards current is unlikely to be substantial (i.e. it will be less than efficiency loss of a diode) and will not damage the panels themselves.

If anyone has a problem with mixing different voltage circuits in a parallel connection, or a problem with not using diodes — speak now or forever hold your peace.

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