Originally Posted by
StephenH
I was looking into solar systems to power a laptop at Christmas, not for a bike, but here at the house.
I think I figured up that with the panel I was looking at, a workable system would cost maybe $150 and power the laptop for a half hour or so a day. This was using components from Northern Tool.
One problem is that laptops don't run off 12v DC, so the simplest way to run it off solar or batteries is to convert the 12V DC to 110V Ac and then use the AC-DC adaptor that came with the laptop. That's an awkward way to do it.
Another issue is that the panel I was looking at was a 5-watt panel. The bigger ones were about 1' x4' and were 15 watt panels. But neither of those was enough to run a laptop. So you'd have to charge a battery all day and then run the laptop a little bit. And the expense is more in the electrical doohingies than in the solar panel itself. The batteries are heavy as well.
For powering devices with solar the trick is to rig the panels to either charge batteries or use the power directly. Any time you convert power from DC/AC or AC/DC you have losses. My current laptop uses 19.5 volts. I believe it would be more efficient to convert from 12vDC to 19.5vDC than to try and go back and forth with the AC adapter. FWIW the laptop takes about 3-4 watts at 19.5.
Aaron
