Sam Deane answers:

Hey C, the answer is you should buy a panel that meets your needs. A 100 watt panel is pretty easy to find, but I’m curious about the desired voltage. Most panels are designed to charge existing batteries, which normally come in multiples of 6 volts. This is why battery banks of 12, 24 or 48 volts are so common, and large deep cycle batteries of 6 volts each so easy to find. A panel set up to charge a 12 volt battery normally has 36 cells in it, which yields an open circuit voltage of 18 volts DC. A panel for a 24 volt battery will have 72 cells, with a V max of 36 volts. If you’re trying to charge a 12 volt battery, 17 or 18 volts will work fine. If you are trying to do something outside the box like directly power your computer (which has a 19 volt power supply) with a 20 volt panel, then you’ll run into some problems that might be too numerous to mention here. Mainly, solar panel voltages are unregulated without a battery to anchor them, this is why they never list a nominal voltage on a panel, only its maximum, it might be anyplace between zero and max if hooked directly to a load. The only exception to this is when hooking directly to a utility intertie grade inverter, they are designed for these large ranges in voltage, almost nothing else is.

If you really want to get involved, here is what I would do. First, get a subscription to Home Power Magazine, it’s inexpensive and right to the point. Then look for an energy fair near you in the Calendar section of the mag when it arrives. Go to one of the fairs, we did 12 years ago, now our home is completely powered by the wind and sun. In the mean time, check out the sources below and learn what you can. One thing I encourage people to do is build up a small system themselves, with a 12 volt battery, panel, and small inverter. Now you can run your laptop, or other small electronics and lighting with your own power source. You’ll have a much better understanding of the entire technology and be more equipped to make decisions. Home Power has great articles about people doing just what you are trying to do, that is why it’s so worth the time and expense. Good luck C, and take care, Rudydoo

Sam Deane answers:

Http://www.thinkgeek.com/gadgets/travelpower/e193/?pfm=Search&t=solar%20laptop%20charger
its a bit pricey though

Sam Deane answers:

Http://www.makeitsolar.com

Sam Deane answers:

Those are 2 different items.

Since each is made along the similar designs of their respective applications, qualities will be about the same across the board regardless of manufacture in either case.

A charge controller is a different beast than an inverter.

You may find this blog of some use. Http://altenciruits.wordpress.com/

he will eventually cover inverters at the level where you could construct your own if you chose to.

It boils down to what additional features on each do you really want?

Sam Deane answers:

Let’s see, a desktop computer typycally has a 500W power supply at 65% efficiency, a typical CRT TV uses 300W so to run those two, you should provide at least (500)/0.65+300 or 1,070 W of photovoltaic cells. The cells are rated by maximum power output in full sunlight so assume you’r only get 63% so that means you’ll want 1700W solar panels. At $10 a watt installed, you’re looking at $17,000 worth of photovoltaics. Of course you can reduce this amount by taking into account how much of the day you actually use the computer, and TV for, selling the power to the grid when you don’t need it and buying it back at the higher power rate when you do but basically, it’s going to be expensive.