Historically, fuel cell systems have relied on power electronics developed for the solar industry.  The solar industry inverters are mature, commercially available and have the appropriate certifications for residential and light commercial use.  They are, however, designed for the solar arrays’ high voltage DC input (200 – 450 VDC) and their efficiency is strongly dependent upon input voltage; the lower the input voltage the less efficient the power conversion. 

In contrast fuel cells produce low voltage, high current, unregulated DC power that is relatively incompatible with commercially available solar inverters. Marathon LR technology bridges between the unique characteristics of the fuel cell and the standard interface of a commercial inverter. 

In addition, Combined Energies design uniquely improves in efficiency as input voltage decreases. In this manner as the fuel cell stack ages and voltage/efficiency drops the net solution efficiency is maintained.