We've all been there, you're listening to your ipod on a long bus trip and it runs out of power in the middle of your favorite song. No listening to podcasts, no music or audio books, what are you going to do with all the time ahead of you. If not that then surely your cell phone has given up the ghost half way through an important conversation. The phone sounds a beep and you see the low charge warning on the screen. Looks like you'll have to find an un-vandalized phone booth - good luck!

I guess I'm as guilty as the next person. I want immediate access to my entertainment or communications devices. This is the reason why I have this and that gadget for all sorts of things. Unfortunately all these appliances need power from time to time and I have forgotten to recharge them leaving me stranded. The way round this common problem is to use a portable solar power generator.

With the interest in solar power and the increase in hand held devices, there a number of good portable solar power generators around at the moment. The standard design is similar for most of them. A solar panel or cells will react with the photons in sunlight to create direct current electricity. This is passed to a battery that stores the electricity. The generator has a power point where various devices can be plugged in to use the current of the battery as if they where plugged into a wall socket.

The best part is that as long as there is some sunlight, your solar generator will always be charged or at least not losing power. Provided there is some sun out, the battery will always be charging. This should mean that whatever hand held device you may be using will always have a potential power source. You'll never be inconvenienced again from lack of power.

When going for a portable solar generator there are a few things to consider. First should be the type, size or efficiency of the solar panels. Bigger panels will obviously have more surface area and thus provide more direct current. This has to be weighed against bulkiness and aesthetic appeal. You want your generator to be compatible in terms of size with the devices it will be powering. And it should be comfortable to carry in a backpack or something like that, without being heavy.

You also want to find out what kind of capacity the battery has. For example, how long will an power sucking device such as a PSP last. The longer this time is the better the battery but again this has to be balanced against the size and weight of the battery if you want a generator that will be completely portable.

Finally, you should check out what portable appliances can be plugged into the generator and how easy this is. At a base level, it should be compatible with your cell phone and any of personal digital appliances you may have (including a gps device if you do a lot of car traveling). You will probably use it most often with entertainment devices like PSP's , portable dvd players and mp3 players so it should be compatible with these devices too.