Design and construction of a portable solar mobile charger.

Abstract

The relentless and continual power failure state accompanied with hike in the fuel and petroleum prices in Uganda, and electricity bills , solar energy becomes the most sought after energy source . Solar chargers are simple, portable and ready to use devices which can be used by anyone especially in the remote areas. Going solar can solve the problem of dependence on fuels and the prevalent energy crisis. This charger is made by converting, controlling and conditioning the flow of electrical energy from source to load according to the requirements of the load; this technology is called power electronics. An external adjustable voltage regulator is used to obtain the desired constant voltage. A zener diode switches on to ensure charging is cut off at the saturation point. The 7.4V lithium ion battery is used as backup; an operational amplifier works here as a comparator to signify when backup is fully charged. Ultimately, 11V and 160mA is supplied by the panel under full sunlight. This charger has an output voltage of 5V and an average of 785mA cur- rent to charge a mobile phone, this system charges a phone fully between 4-5hours and it has a capacity of 4800mAh. This device charges all mobile phones by all manufacturers using a universal serial bus connector. It is the only viable solution to charging mobile phones as it is portable, light-weight and does not cause pollution. a photovoltaic cell receives sun s radiation, and converts into electricity transferred to the solar panel that is utilized for charging .