Portable solar for limited current draw

Isaac-1 wrote:
There is not nearly enough information here, what type of laptop, some newer ones draw 20 watts or less while running, others draw 75 watts or more. How many hours per day do you want to run the notebook computer, is this just to check email or do you spend 16 hours per day in front of the keyboard? Either way charging a deep cycle battery with the solar panel/panels and using an inverter to power the notebook computer is probably the best way to go. You could get a DC-DC power adapter for the notebook computer, however the efficiency difference vs using a modern inverter will be trivial, as DC-DC converters are basically a DC-AC inverter coupled to an AC-DC switch mode power supply.

Having said all of this a good rule of thumb on solar panels is that on average you will get about the equivalent of 5 hours of rated output out of a panel per day, and that you will loose about 25-30 percent by storing it in a battery.

To put that another way expect to get about 500 watts per day out of a 100 watt solar panel, then expect to loose about 150 watts of that storing it in a battery leaving you with about 350 watts of power on a sunny day to use out from a 100 watt panel. Which would be enough to power a notebook computer that draws 35 watts for 10 hours per day, or enough to power a notebook computer that draws 70 watts for about 5 hours per day. This does not count power for a water pump, interior lights, furnace blower, etc.

p.s. I have 400 watts of solar panels on the roof of my coach, and would not want to try to survive with anything less, this lets me use low power LED lights when I want, power water pump, and furnace blower on cold nights, charge my cell phone, use my notebook computer a few hours per day, maybe watch tv for an hour or two, etc.