Solar Powered Module for Portable Computers

A laptop by its virtue is a mobile apparatus, therefore, a power outlet may not necessarily be available to charge its batteries. Typical laptops have a range of up to 2.5 hr. of battery life under normal operation and some have as little as 1.5 hr. For the computer user on the move, it is important to have enough power available for more extended periods of time. Today’s technology provides a large number of other mobile appliances, instruments, and tools that will also greatly benefit from extended power. Existing solar panels operate under direct sunlight conditions and are deployed only when the equipment is in use or stationary. The solar-powered module developed at the Department of Mechanical Engineering, University of Puerto Rico-Mayaguez, has the advantage that it recharges the laptop in transit even when it is not in operation. By charging the battery when it is stored allows the battery to be recharged during a larger period of time thereby increasing the amount of energy stored. Different types of solar cells were tested under “real world” lighting situations in order to assess their potential for the intended application. The solar array was optimized for use under a larger range of illumination conditions such that it may operate when direct sunlight is not available. The ergonomic design is integrated into the laptop’s carrying case, but it may also be detached and/or repositioned if desired. The solar panel is based on the latest technology of triple junction spectrum-splitting amorphous silicon solar cells. The equipment allows the use of a laptop or other portable equipment in situations when power is not available, providing a needed service in remote locations to professionals in the field and provides a backup power source in the event of an emergency or lack of adequate infrastructure. This paper describes the design process in the selection of the solar cell technology used in the module.