Wednesday, December 12, 2012

Solar Powered Smartphones

Negative news about solar power handsets

Nokia and some solar-powered smartphone research teams concluded that this technology was impractical. Their test project was conducted in various regions of the world including the Arctic Circle all the way to the African continent. The prototype test phones were constructed with a solar panel at the back of the phone to provide power from the sun in areas where no electrical outlets are available. According to their test results, the power output from the solar panel was able to keep the smartphone on standby mode but is insufficient to keep the phone running under normal applications such as web surfing, playing video and audio, messaging and calling. This limited power according to them was because of the small area of the solar panel and the difficulty with exposure to sunlight especially in the some areas of the Northern Hemisphere.

Don't pay so much attention to these negative thinkers! The good news is, there are already a number of promising developments in solar-powered smartphones.

Smartphone displays with solar cells

It is undeniable, yes, smartphones are technologically advanced in terms of applications, speed, 3D graphics, gaming, Wi-fi, and GPS... but these all drain the battery in a frustratingly very short period of time. You will end up desperately looking for an electrical outlet to charge your mobile device. This is the main reason why researchers are constantly developing longer lasting batteries and looking for ways to conserve energy and improve battery efficiency.

A research team from the University of Cambridge in UK is working on a prototype handset that generates power to run the phone from surrounding light sources available. This smartphone solar power source is achieved by utilizing an OLED (organic light-emitting diode) display that is made of solar cells. Because typical displays only require about 36% of the light to generate images, the model was incorporated with photovoltaic cells (solar cells or photoelectric cells used to directly convert light energy into electricity) all around the edges of the display screen. These cells can capture the light energy that escapes from the edges of the screen thereby conserving and reusing the energy. If this technology will become successful in the near future, it would solve most of the battery power shortage problems that we experience today due to power hungry applications running in smartphones.

Solar powered smartphones without solar panels

Researchers from the University of California, Los Angeles (UCLA) have developed an LCD screen display that does not need solar panels for recharging. The innovative screen is able to charge the battery using any available light source, indoors or outdoors. This means that it can use the light energy from the sun, fluorescent lamp, study lamp, light from a TV, laptop, and even the smartphone's own backlight to charge its battery. The special LCD is constructed with photovoltaics which convert the energy from the polarizing sheet with little or no waste of energy.

Samsung solar-powered laptops and smartphones

During the 2011 IFA consumer electronics trade fair demos and exhibitions in Berlin, Samsung featured a partially solar-powered laptop called the Samsung Note PC having a solar panel on its lid as well as a solar-powered smartphone with a solar panel for charging its battery. Samsung previously developed the Blue Earth smartphone and notebook computers which utilized solar panels for charging these devices' batteries. The Blue Earth was the first solar cell phone designed to be an environment-friendly mobile device. It has a charging rate of up to 40 mAh per hour. Samsung is planning to manufacture in mass production smartphones and tablets with solar panels in the coming years.

Solar-powered consumer electronic devices are coming soon! Apple is also planning to produce smartphones and tablet computers with solar panels in their products such as the famous iPhone and iPad devices. Solar technology firms such as SolarPrint in Ireland said they successfully imitated how plants harness energy from sunlight through photosynthesis. The company further said they were able to harvest ambient or diffuse light in any angle. Wysips, a French-based technology firm has developed a transparent coating for LED screens which can be used in a smartphone to allow it to fully recharge in about 6 hours under direct sunlight. The LED display screen is also able to charge using ambient light and indoor lighting which takes longer time to charge compared to the sun's light rays.

Solar panels exposed to direct sunlight for 1 hour can translate into 20 minutes of talk time. This means that when exposed for 3 hours, the solar powered smartphone can provide 60 minutes (1 hour) of talk time. Some solar panels provide about 3:1 exposure time to usable time. Some solar powered smartphones with better technology can harvest half an hour of talk time after 1 hour of charging time under direct sunlight. This equates to 2:1 exposure to talk time ratio. Solar powered smartphones can be recharged in about 6 hours under direct sunlight.

Smartphone and Laptop Batteries

Old laptops previously used Ni-Cad (Nickel-Cadmium) batteries as a secondary source of power. These batteries however drained quickly and were hazardous to the environment if not disposed properly. As a result, NiMH (Nickel-Metal Hydride) batteries were used and they provided longer running lives, better efficiency, and eco-friendly alternative source of power. NiMH batteries can be charged up to 500-1000 times and last longer than alkaline or NiCd batteries.

Nowadays, laptops and smartphones use Lithium-ion and Lithium polymer batteries. These batteries have lower discharge rates, lasts longer, and offer better efficiency than NiMH batteries. Lithium phone batteries usually have 300 to 500 charge and discharge cycles.

Charging times

The mAh capacity of a battery is the amount of electrical energy that the battery is able to store. A battery with a storage capacity rating of 1880 mAh can deliver a total current of 1880 mA for a period of 1 hour. My Motorola Atrix 4G smartphone has a battery capacity of 1880 mAh and allows me to use it for a continuous time of 6 to 10 hours depending on the running applications which consume big power such as video and audio playback, wi-fi web browsing, or 3G/4G internet surfing. Batteries with higher mAh capacity ratings will last longer and provide longer usage time.

To calculate how long is the charging time for a rechargeable battery, divide the battery's storage capacity (mAh) by the charger output current in mA.

Charging time = Storage capacity/Charger output current

Motorola's dual core processor Atrix 4G smartphone has a battery capacity of 1880 mAh. The charger output specifications indicate 5.1 V and 850 mA output current. Determine how long does it take to fully charge the smartphone when it is fully drained.


Charging time = Storage capacity/Charger output current

Charging time = 1880 mAh/850 mA

Charging time = 1880/850

Charging time = 2.2 hours

Battery life of current smartphone models (2012):

Battery life specifications provided by vendors are very frustratingly deceptive and misleading.

They would indicate a 10 hour usage time but in reality this is actually only 5 hours (half). What is the reason? Because they would like their product to sound good and look good and be sold, therefore, they cheat. They conduct their test under light load conditions. They test the battery with 40 to 50 percent screen brightness, Wi-Fi feature is turned off, no video or audio playback, etc. These do not reflect normal regular usage of smartphone owners. The worst thing is, they hide these testing conditions in fine print or even do not print it at all. May God admonish you, you cheating sellers and liars!

Two of 2012's smartphones with the best battery performance are the Motorola Droid RAZR Maxx 4G and the Sony Ericsson Xperia Play. Using the Laptop Battery Test with 40% brightness and continuous web surfing over 3G and 4G networks, these handsets lasted for at least 8 hours. The Motorola Droid RAZR Maxx 4G smartphone has dual-core processors and 8-MP camera. It has a Lithium ion battery with a capacity of 3300 mAh which can be used for a continuous talk time of up to 1290 minutes (21 hours) and standby time of up to 380 hours.

The Sony Ericsson Xperia Play is a smartphone and a gaming platform. This is a cell phone and a Sony PlayStation Portable (PSP) console in one. Under the LAPTOP Battery Test conditions, this mobile device lasted for an almost 10 hours of continuous running time, making it one of the longest lasting smartphone batteries of the year.

Smartphone solar chargers

Typical smartphones have 6 to 10 hours of continuous use under normal running of applications. It is often frustrating that you run out of battery power even before lunch time. Heavy smartphone users either carry a second battery pack as a backup and a solar charger in case of lack of power charging outlet.

While waiting for the solar-powered smartphones, tablets and laptop computers to be mass-produced, electronic gadget users can use solar chargers for the meantime. Additionally, for heavy users of eletronic devices, they can bring with them an extra battery pack. Commercially available solar chargers are designed to be used as a battery charger and a backup source of power for Cell Phones, Smartphones, iPhones, iPods, MP3 players, Bluetooth headsets, and most USB-powered devices. The best solar chargers have a built-in Lithium Ion battery that can be charged through a computer or electrical outlet using the provided USB cable as well as using energy from sunlight via the solar panel. These solar chargers are perfect for both indoor and outdoor usage which is very handy and useful for campers, hikers, and travelers.

Typical solar chargers have charging capacities of 2,000 to 10,000 mAh. One of the largest capacity solar chargers has 23,000 mAh for smartphones, iPods, iPhones and iPad tablets. The charger DC output current is 2A (2000 mA) with 9V, 12V, or 16V output voltage. Under USB, the charger output current is 2A and 5V output voltage.

Commercially available solar chargers include a built-in lithium-polymer battery with 10 charging tips (adapters) with USB port to maximize compatibility. These 10 mobile-device connecting tips, extension cable and USB port ensure the solar charger is compatible with most smartphones from manufacturers such as Sony, Samsung, LG, HTC, Palm, Blackberry, Apple, Motorola, and Nokia. Also, these 10 connector charging tips can be fitted for charging most Bluetooth devices, GPS, digital cameras, PSP gaming consoles, eBook readers, tablets, Nintendo DS, Amazon Kindle, and other electronic devices.    

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