Charging a computer directly to a USB port.
George Harvey
Sometimes things work exactly as I think they should, and yet I feel a sense of astonishment that they do. This is one of those times.
Right now, I am typing away on the article you see before you, using a computer that is powered directly from a USB port on the side of a 20-watt solar photovoltaic (PV) panel. All of the electricity for the computer, its monitor, and the dongles that connect it to its wireless keyboard and wifi, is supplied by that panel. And everything is going along without any problem. More amazingly, perhaps, is that the entire solar PV system is highly portable and costs only $85.50.
Truth be told, it was an unfair test. I could have plugged in a cell phone or two, and possibly a battery to be charged, and still have run that computer without a problem. The computer system, a Raspberry Pi 1 Model B, with its seven-inch monitor and the dongles, draws only a trifle more than four watts, leaving a lot of power for the panel to apply to other things. Assuming the local Wi-Fi works properly I could use the computer to check the news, surf the internet, or talk to a far-off relative on Skype.
We have come to a new age for solar power, as well as of tiny, highly useful systems. And to some degree, we in Vermont can thank Joe Yoder, the owner of TinySolar Vermont, for an amazingly small but truly significant proof of that.
Yoder became interested in solar power early on, but as he got to an age when he felt it might not be best to go up on roofs to install systems, he decided to consider a different business model for solar power. He started TinySolar Vermont in 2014 with a stated goal of designing and selling “very small, very affordable solar electric systems and related materials.
Larger TinySolar Vermont systems include solar panel, charge controller, battery and inverter. Images courtesy of TinySolar Vermont.
The TinySolar Vermont website, tinysolarvermont.com, is a place to go to buy small solar systems. The PV systems range in size from 20 watts to 150 watts. While the one I have been using has no battery, the others include them.
I should mention that the specifications on these systems are not written in stone. Yoder said that the biggest problem with building such systems is sourcing the small components, and they become unavailable really easily. His approach is not one of mass producing a product, so having a single source for all products is not the issue it would be in a bigger business. And TinySolar Vermont is a place where a custom design is not a difficult problem.
The system I got consists of a 20-watt panel mounted in a frame, with wiring on the back leading to a 12-volt cigarette lighter receptacle. Into this is plugged a separate device with a standard USB port. Larger systems include batteries, which are usually sealed or flooded lead-acid types.
You might ask why anyone would want a 20-watt system. There are lots of reasons to have a system like this. These systems are light enough to carry, and that means, for many people, light enough to use when you go camping. Or when you want to type an article in the back yard on a hot day in July. (And by the way, to be truthful, I have moved back indoors because it is just too hot to work outside today.)
Some of the reasons to have a system like this are rather surprising. Yoder talked about one person who had a series of automotive batteries in vehicles that go dead when unused for months at a time. A single small panel was able to keep a battery continually topped off.
In another case, he came across one person who had a large storage system that was charged by a single panel. The system was used to supply electricity to a retreat that was only used for one or two days on weekends. It had all week to be charged.
One woman lived off-grid for many years, without any hope of getting any electricity because there were only a few places at her home that got any sunshine, and none of them got it very long. She was able to move a small, portable panel among morning, mid-day, and afternoon charging stations easily.
There are other potential uses for very small PVs. For example, batteries lose cranking power in low temperatures, so small PV can also be useful to keep a battery that starts a standby generator from getting too cold in the winter.
Altogether, I have been through four power outages that lasted upwards of a week. From those experiences, I can say with absolute certainty that a tiny amount of electricity is a whole lot better than none at all. I think that everyone should have a small PV system like those available from TinySolar Vermont, just for emergencies.
Again, the TinySolar Vermont website is tinysolarvermont.com.
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