Hi, I purchased a solar panel that is capable of 4 watts. These are commonly used by Volkswagen to trickle-charge their car batteries when cars are shipped across. (http://search.ebay.com/vw-solar-panel_W0QQsojsZ1)
The panel is compact and easy to carry. Here are some observations that I'd like to share: I drained the battery as much as I could (loaded the USB port with a USB light attachment) so that it was near zero. Then, I plugged in the solar panel. The panel starts of at about 9.5 Volts in the morning with indirect sunlight (8am) and will start pushing 13.9 volts by 10:30am, or so. The panel does have a diode to prevent reverse flow. In the beginning, the laptop keeps showing a red LED light that will blink every few seconds. The laptop also emits a high pitched sound from around the power plug area. This sound will change its pitch as I move the panel from a horizontal to a vertical position, in the direction of the Sun. Pitch increases as light increases. At around 11am, the sound goes away and the charging LED turns to yellow. If I leave the panel in my car's rear window at an angle (so that it catches the sunlight from around 10am to 4pm) I get a total of 16% battery charge. I'll repeat these setups to see if I get stable results. Of course, suggestions are welcome. Questions: Is the high-pitched sound indicative of damage to the power electronics in the XO? Is the sound emitting because the panel does not spit out a full 12 volts? Will I get a better charge profile if I start with the battery charged part way (LED shows yellow instead of red)? Is the "official" solar panel much better because its a 5 watt panel (will 1 watt make such a difference)? Sameer -- Dr. Sameer Verma, Ph.D. Associate Professor of Information Systems San Francisco State University San Francisco CA 94132 USA http://verma.sfsu.edu/ http://opensource.sfsu.edu/ _______________________________________________ Olpc-open mailing list [email protected] http://lists.laptop.org/listinfo/olpc-open
