Where can I learn about Solar Rechargers?

First of all, go take a quick course in basic electricity. Things like Volts, Amperes, Ohms, Watts, etc. are not difficult. If you compare the power characteristics of two load devices, you may see some subtle differences.

Some users focus their thought on the output rating of the solar panel. How about studying the power input ratings of your load devices? Sometimes one manufacturer will have an awkward specification, and they want the users to purchase some special charger to overcome this. Often they will just accidentally fail to publish that awkward specification and then just let the new user fall into the pit. Then, if you inquire, they will not give you the number in black and white.

Second, you want to understand that most portable solar panels are rated highly, but that may not meet up with reality. If you have a portable solar panel mounted perfectly with respect to a strong sun, then often you can get close to the rated wattage coming out. Then, with proper charge control and utilization of the power, it can seem pretty good. In other words, just because a panel is rated at 10 watts, that doesn't mean that you can expect to get 10 watts out of it. Electrical resistance increases with temperature, and that represents loss in your solar panel. So, some manufacturers do their product tests on panels that have been cooled. That helps their numbers just a little.

Too many users can't get the rated power out. Suboptimal mounting angles can easily reduce power by 50%. If you are moving from sun to shadow to sun, you can easily reduce power by another 80%. Charge controllers help a lot.

My rule of thumb is that I figure out how much power I need in a solar panel, and then I increase that by a factor of five or ten. That's what I purchase. I could get by with less, but then I would spend all of my time fooling with the angles.

I never use my portable solar panel unless I am going to be gone on foot for a long time.

–B.G.–

Another thing that can be handy is an electrical multimeter. When you can measure volts and amperes, you can close in on the prey. A normal multimeter will fill up your shirt pocket, though, and that starts to defeat the ultralightweight purpose.

I purchased a tiny multimeter. It is smaller than a pack of chewing gum, and it plugs directly into the USB connector that is often found on solar rigs. It alternates its display between volts and amperes. This way, if I am trying to orient the panel for sun angle, I can see the output displayed.

–B.G.–

Bob,

Thanks. Going to start with the electricity course. What multimeter are you using?

"It is smaller than a pack of chewing gum, and it plugs directly into the USB connector that is often found on solar rigs. It alternates its display between volts and amperes."

If you can't buy it on Amazon.com, it probably doesn't exist. The one that I have is called Charger Doctor.

–B.G.–

Something to consider is that solar panels don't necessarily output their max output. They have to be in direct sunlight at a good angle to output what manufacturers advertise.

Because of this, you almost always have to have a battery set up for trickle charging to save the output from the solar panel, because many devices will refuse too low a power input. Just because a plug fits doesn't mean it is outputting power to correct specs, and devices that receive power may cut off incorrect power sources to protect themselves.

It then becomes a problem of finding a way to send juice to your laptop from said solar battery without the expensive DC->AC->DC process that a normal laptop wall wart would use and at a high enough wattage to satisfy your laptop.

I see that Voltaic Systems offers one such full system, but know nothing more about it than what their website provides.

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