I've been doing some research into this, and wanted to know if anyone here had come across anything similar or mac specific. i wanted to kno if there was a way to create a solar power recharger for a laptop.
any ideas? from what i kno, the difficulty would be converting the power from an irregular source to a constant source.
feel free to use engineering language.
wow, there's an ad for solio at the bottomof the page. didn't know these ads were targeted! Anyways, i was looking for something that could be built in.
It's common for people on sail boats to depend on wind and solar power. I've learned a little through that route. First off the solar system you propose needs to be rather large. What you need to determine is the ratio of charge time to use time. Do you want to charge the system for three days so that you can use it for three hours. Or would you prefer to fully charge a dead battery in three hours. Or do you want to be able to use the notebook and recharge it at the same time.
In the sailboat case, people make an energy budget based on (say) 1 hour of usage every day for a computer (for weather faxes, email,..) and then the lights, water maker and so on. So your first step will be to determine how many Watts of power you need.
Next a few real world engineering guidelines.....
The best way to do this is to use a deep cycle lead acid storage battery connected to the solar array. This gets charged whenever the sun is out. For a small array you can simply us a diode as a "controller" so the battery does not discharge through the array at night. Then you connect an AC inverter to the lead acid battery. and you connect your Apple AC adaptor to the inverter.
You need to de-rate the sollar panne's published power in watts y a factor of two. Reason being is that rateedpower happens only at noon what the path of sunlight through the atmosphere is minimum. At other times you have longer path. Also account for the fact that your pannels are not mterized and do not track the sun. Factor of two works well. This assume no shade and you pannels are tilted to angle equal to your longitude. and facing due south De-rate father if you can't angle the panels correctly.
Next assume an 8 our day on yearly average or for any given day only 3/4 of sunrie to sunset hours are usable.
Size the storage battery "way large". The lifetime of the battery depends on the level of discharge. Going past 50% will kill even a deep discharge battery quickly. Buy at lesat 4x as many amp hours as you need
It should be clear that a 100W charger s not a portable device. It will take about 300 pounds of equipment to do it right.
The other way to go is to skip the storage battery and AC inverter. I don't think this is as practical. You would only be able to charge the notebook when the sun is overhead and you would still not have a portable system. The way to do it would be to buy a panel that puts out abut 16V and then use a DC regulator to supply the correct charging voltage to the computers. But you don't save much a 100W panel is never going to be portable
Adding a storage battery means you can use a much smaller solar array. Batteries are cheeper than panels. With the battery all the sunlight is put to use without a battery the sunlight is only put to use when the notebook is plugged in. With a battery you can charge the notebook at night
One more idea: For a small system, you could buy a small UPS. Connect the solar array to the UPS' internal battery (diode in series) then you plug in the Apple AC adaptor to the UPS. Yo are ineffect using the UPS as a battery and inverter saving some work
