Over 90 % of the worlds solar cells are made from silicon but they are not particularly efficient at converting light to energy. They are made from layers of high purity crystal more than 150 micrometers thick which is costly to produce. Thin-film solar cells are an alternative technology; they convert the sun’s energy using a more efficient semiconductor process and can get similar efficiency using lower purity material that is only 2 micrometers thick. This results in much lower production costs.
The majority of thin-film cells are made from a sandwich of cadmium telluride and cadmium sulfide (CdTe/CdS) which, thanks to recent advances are now approaching the efficiency of silicon cells. The problem with this technology is that cadmium based products are extremely harmful to living organisms. Researchers at Liverpool University in the UK have discovered that magnesium chloride is a good alternative to cadmium chloride. It is extracted from sea water and has uses such as road de-icing and as a coagulant for tofu, the vegan protein foodstuff based on soy milk.
Vegan Additive makes Non-toxic Solar Cells - [Link]
mjlorton @ youtube.com writes: In this video I go through the components that are part of a solar power solution. I explain the differences between On-grid vs. off grid.
How to Solar Power Your Home / House #1 – On Grid vs Off Grid - [Link]
By Dexter Johnson:
Quantum dots have offered an attractive option for photovoltaics. Multijunction solar cells made from colloidal quantum dots (CQD) have been able to achieve around 7-percent conversion efficiency in the lab. While figures like this may not seem too impressive when compared to silicon solar cells, their promised theoretical conversion efficiency limit is an eye-popping 45 percent. This is possible because when a single photon is absorbed by a quantum dot, it produces more than one bound electron-hole pair, or exciton, thereby doubling normal conversion efficiency numbers seen in single-junction silicon cells.
Quantum Dot Solar Cells Break Conversion Efficiency Record - [Link]
Raj @ embedded-lab.com writes:
This instructable describes in detail the setting up a full-featured weather station that records air temperature, relative humidity, and ground surface temperature right below the weather station. The project uses Phidgets SBC3 computer board, which is powered by an 18-watt solar power along with a battery backup.
PhidgetSBC3 based solar-powered weather station - [Link]
In December 2013 Linear Technology announced a new chip – LT8490. This chip includes a 80V Buck-Boost Lead Acid & Lithium Battery Charging Controller that actively finds true Maximum Power Point in solar applications.
No yet available, that chip looks very promising. It operates with input voltages down to 6V and can boost that to charge batteries with higher voltage. I made already a schematic and board design from the preliminary datasheet that charges a 3S LiPo from a solar panel with up to 5A. A small board size allows usage in model gliders with large wing span to charge the battery in flight.
Solar charger with MPPT - [Link]
Heinz Pieren writes:
ArdaSol is the project name for my solar energy and Arduino based monitoring system. This description shows how the system is built and how it works. The energy production of a photovoltaic plant is monitored and also the consumption or feeding to grid of the energy. Data acquisition during a solar day and publishing on the internet is also a function of this system.
ArdaSol – Photovoltaic Energy Monitoring System - [Link]
Maximum power point tracking (MPPT) is a technique that solar battery chargers and similar devices use to get the maximum possible power from one or more solar panels (several solar cells connected in series and parallel). Solar cells have a complex relationship between solar irradiation, temperature and total resistance that produces a non-linear output efficiency known as the I-V curve. It is the purpose of the MPPT system to sample the output of the cells and apply the proper load to obtain maximum power for any given environmental conditions.
Solar Cell MPPT - [Link]
A solar charge controller regulates the voltage and current coming from your solar panels which is placed between a solar panel and a battery .It is used to maintain the proper charging voltage on the batteries. As the input voltage from the solar panel rises, the charge controller regulates the charge to the batteries preventing any over charging.
Arduino Solar Charge Controller (PWM) - [Link]
The organic solar film producer Heliatek based in Dresden, Germany have announced an improved type of solar cell which gives a transparency of 40 % while achieving 7 % energy conversion efficiency. Although its efficiency is not as good as the company’s opaque organic cells (roughly 12 %) this new solar film can be discreetly integrated into building and vehicular glazing to provide an energy harvesting tinted transparent film. The film is also effective at low light levels and high temperatures where conventional cells lose out.
HeliaFilm uses small molecules (oligomers), developed and synthesized at Heliatek. Oligomers are deposited at low temperatures in a roll-to-roll vacuum process and by changing the spectral absorption properties of the molecules the film can provide different levels of transparency and a colored tint. According to Thibaud Le Séguillon, Heliatek CEO “The transparency of our products is at the core of our market approach. Our HeliaFilm™ is customized to meet our partners’ specific needs, we are a component supplier and this component is a film which can combine transparency and energy generation. This unique combination widens our market potential.”
Organic Solar Film adds Tint and Power - [Link]
Startup company Aquion Energy gave MIT Technology Review a behind-the-scenes look at their battery manufacturing process. The company’s goal is to make non-toxic, cheap batteries for storing off-grid energy. The batteries will first be sold in regions that don’t have access to an electrical grid, such as rural areas and villages in poor countries.
How to Make a Cheap Battery for Storing Solar Power - [Link]