Sameer Verma wrote: > 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 > >
Is anybody using solar for charging the XO directly? I'd like to hear more on your experiences and ideas. 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
