Tuesday, October 19, 2010

How to select a solar charger for your mobile phone

A popular eco-friendly  way to keep your mobile phone charged is with a solar charger.
Most of us are confused by the available variety of these solar powered battery chargers, so what do you need to know before you choose one?
There a two important considerations

How powerful does the solar charger need to be?

Look at the nameplate data on the original charger, the one that came with the mobile phone. Read the part that states the output DC volts and milliamps, for example it may have OUTPUT DC 5.0 volts  900mA. This tells us the charger  provides a voltage of 5 volts, so the solar charger must be capable of providing 5 volts output as well.
You can use a charger that puts out a bit more voltage, say 5.5 volts or 6 volts but not less than 5 volts.
Why? ok here's a basic lesson in electricity: Volts is the pressure of the electricity in the wire. Let's compare electricity to water. Imagine you have long garden hose and you are trying to fill a water tank on a hill high above the  tap, now if the pressure of the water system is too low you won't be able to fill the tank because the system water pressure is too low to push the water up the hill, it's the same thing with electricity if the voltage (electrical pressure) is too low it wont flow through the circuit.
Amps is the current flow. Getting back to our garden hose, this can be compared to water flowing through the hose, A high water flow will fill the water tank sooner. Therefore a higher  amperage will recharge your battery sooner. A solar charger that supplies more amps is preferable to one that might supply the same voltage but a lower amperage.
A very high amperage can burn out the electronic circuit, but with solar cells that's not a problem because they are too small to provide a high current flow.
Ok, here's a quick lesson in photovoltaics:  All solar cells provide about 0.5 volts, that's a matter of physics, so to get 6 volts twelve cells are connected together like beads on a string. This string of cells might only provide 0.1 amps (100mA) The solar cells are glued to a backing board and there you have solar panel. The power (Watts) this solar panel can generate is calculated by multiplying the volts times the amps. so 0.1 x 6 = 0.6 watts (600mW)
Remember our garden hose? that's like the quantity of water it can provide in certain tome so water pressure times water rate of flow equals the quantity of water in given time and Volts X Amps = Watts, same thing! simple Hey!

What cable and connectors do you need



All solar chargers come with several adaptors to fit various mobile phones and also other popular personal electronics like Ipods, iphones and MP4 devices. Look at the wide range of solar charger adaptor tips that are available. The good news is the later model mobile phones are standardizing their power adapter tips, this will make your selection easier. The modern trend is toward the micro- USB plugs like those used with the latest Nokia phones.
But always confirm the compatibility of the adaptor tip with your mobile phone because some tips look identical but may have different pin configurations.