The Use of Solar Chargers

a Solar Charger

Today’s electronic age provides millions of new opportunities for people of all walks of life – and this includes photographers, writers, travelers, backpackers, and even mountaineers who may be far away from a power supply when they need to use their digital cameras or other electronic equipment. Along with the new horizons and possibilities brought about by the digital age, come certain challenges. One of these challenges is – “how can I use my electronics when I’m deep in the wilderness?”

One method of meeting this challenge is the use of portable solar power devices .

But if you are looking for a portable solar power, you might feel confused about all of the different sizes, shapes, versions, and ratings of the various items available.

You might want to know how long it will take for a solar cell to charge your camera or batteries. Or whether or not your power supply will allow you to run and charge your laptop at the same time. Which portable solar device is correct for you, and how much money do you really need to spend?

To make the estimations and predictions necessary, in order to choose the correct device to suit your needs, it will probably be helpful to have a little bit of knowledge concerning electricity.

First of all – what is a watt? (Pun accidental!)

A watt is a unit of electrical power, equal to the power produced by an electric current which has one ampere and one volt.

A watt-hour is a unit of electrical energy, equal to the energy of one watt operating for one hour.

A milliwatt (symbol mW) is one thousandth of a watt. A milliwatt-hour is equal to the energy of one milliwatt operating for one hour.

A fully charged battery contains a certain number of watt-hours or milliwatt hours.

Today, solar chargers for batteries exist on the market which use the power of the sun to charge a battery in the sun, during the day. The battery can then be used, day or night, to run or charge your other electrical equipment.

Now, lets say you have a solar panel which you can use to charge a backup battery, and you can use that backup battery to charge your equipment. You want to know how long the backup battery will last, when you are using it to run one of your devices.

You can make an estimation of this, if you can find out how many watt-hours or milliwatt hours the fully-charged backup battery contains, and if you can find out approximately how many watts or milliwatts your equipment uses per hour.

Let’s take the example of a laptop computer.

1. With your battery fully charged, turn on the laptop, and then unplug it. Look at the power meter to find out how many hours your battery will last. (You might want to test the accuracy of this data, by using the laptop on only battery power and seeing how long it runs.)

Let’s say that you can run your laptop for 8 hours on battery power. (Remember the amount of hours it runs will probably vary, depending on your power settings for the laptop and what you are doing with it. But you can try to find an average.)

2. Now turn the laptop off and take the battery out. Look at the data written on the back of the battery, and try to find out how many watt-hours or milliwatt-hours that battery contains.

In our example, it contains 80 watt-hours. Divide that number by the number of hours you found in Step 1 above.

80 divided by 8 equals 10.

So we estimate that the laptop uses approximately 10 watts per hour.

3. Now find out how many milliwatt hours your solar battery backup contains, when it is fully charged (these backup batteries are often used in conjunction with solar battery chargers). You can usually find this in the specs of the item, where it is advertised (if you haven’t purchased it yet).

In this example, let’s say the fully charged backup battery contains 60 watt hours.

Your laptop uses approximately 10 watts per hour.

60 divided by 10 = 6.

Theoretical conclusion – if you charge your laptop from a fully-charged solar backup battery, it will run for approximately 6 hours.

But there are several other factors which influence this. This includes the settings of your laptop, what your laptop is being used for and how hard it has to work, how old your battery is, the temperature in which your battery has been stored, and probably some other factors only understood by God.

4. Now, not to thoroughly confuse you, but what if you don’t have a solar backup battery, but you have a solar charger for your laptop? And what if you want to know how much “sun time” you will need, to run your laptop for a certain period?

It’s impossible to say exactly, there are variables.

The amount of power generated by the solar device depends on the intensity of the sun, how much impediment there is to the sun, and the length of exposure to the sun. The charger will create more power in the middle of the afternoon, than it will at other times of the day. It will create more power when it is closer to the equator, than it will in far northern or southern regions of Earth. It will also create more power on a clear day than it will in cloudy, misty, or dusty conditions.

But if you want to make an estimation, try the following.

Find out how many watts your device produces under full sun.

Then look at the power adapter of the device you want to charge. Under the output rating, it should state a certain number of watts. If it doesn’t give the watts, it should give the amperes (amps) and the volts.

Multiply the amps times the volts, and you will get the watts:

Amps x Volts = Watts

We will say, for example, that the output rating is 60 watts. Remember, that’s the maximum amount of power that your device will use. When the laptop is turned on, operating, and charging the battery at the same time, it uses more power than it does when it has less work to do. It may have power-saving options which allow it to use less power. It will also probably use less power if it is only charging the battery but is not turned on (or if it is turned on but the battery is already full).

In any case, to estimate how long it will take to charge your battery (under full sun) use the data on the output rating of your adapter.

If the output rating is 60 watts, and your solar charger is 15 watts, you could estimate that it will take the solar charger 4 times longer to charge your battery, than it would take to charge it from a wall socket.

So… if charging your battery takes 2 hours from the wall socket, then charging it from your solar charger under the same conditions (and under full-sun) would take 8 hours. Remember that full-sun, if it occurs, only occurs in the afternoon, and it does not usually continue for an 8-hour stretch (unless maybe you are in the Sahara). So you will have to make allowances for this.

And… the ultimate test? Get your solar panels and your equipment, go up on a mountain top, and see what happens. (Or, maybe you can try it in your backyard first.)

Solar energy is still a pioneer field!

The information above is to help you choose which portable solar device will best suit your needs. Once you have obtained it, experimentation will tell you in the end, what results you can achieve.

And - who knows, portable solar power devices may some day become much more powerful. Solar energy may someday be an element of a better future for all of us, and a key to a cleaner world.

Future development may make it efficient enough to replace the use of fossil fuels, which are creating the pollution that is so damaging to this planet. Some individuals on this earth may not want this to happen (if they are making a lot of money from fossil fuels).

But the sooner we all understand solar power, the sooner we can effect a change.

P.S. If you feel utterly confused right now, try sketching this all out on paper. If you ever need to choose a portable solar power device to suit your needs, this information may be very important for you. If you still feel confused after sketching it out, contact me and I will try to make my article clearer!