Maximum power point tracking charge controllers for telecom applications-analysis and economics

Simple charge controllers connect photovoltaic modules directly to the battery bank resulting in a significant power loss if the battery bank voltage differs greatly from the PV Maximum Power Point (MPP) voltage. Modeling work at AES has shown that DC-DC converter type MPP tracking charge controllers can deliver more than 30% more energy from PV modules to the battery when the PV modules are cool and the battery state of charge is low-this is typically both the worst case condition (i.e., winter) and also the design condition that determines the PV array size. Economic modeling, based on typical telecom system installed costs shows benefits of more than $3/Wp for MPPT over conventional charge controllers in this application-a value that greatly exceeds the additional cost of the DC-DC converter