Single Photovoltaic Cell Charger

NTT Energy and Environment Systems Laboratories aim to go green by working on a circuit module which is able to charge a lead storage battery with but a solitary photovoltaic cell.

This circuit module consists of a boost circuit with a DC-DC converter and an IC equipped with the “MPPT (maximum power point tracking)” function. The boost circuit can increase the typical voltage of a single photovoltaic cell, about 0.5V, up to 15V. The MPPT is a function to maximize the output from a photovoltaic cell in accordance with the change in sunshine conditions.

While using MPPT has increased the amount of electricity generated per day by 1.5 times, the boost circuit’s efficiency is still considered to be low standing at 70% to 80% – although that can be changed depending on the type of inductor used. Hopefully this technology will be perfected so that us cell phone users no longer need to tote around our chargers whenever we travel, relying instead on the sun’s rays to keep us talking.