A method to track the maximum power of multiple-input, portable, photovoltaic systems is proposed. The method shares a single current sensor by interleaving Perturb and Observe operations. The system has reduced size and cost, making it attractive for compact portable solar panels and solar battery chargers, such as for cell phones, laptops, and other portable electronics with rechargeable batteries. A flexible total system architecture design is proposed and tested. (C) 2011 Elsevier Ltd. All rights reserved.