A zero-dimensional electrochemical model of the Fe/V redox flow battery (RFB) is presented that can model RFB performance at low flow rates (< 0.5 mL min(-1) cm(-2)) and varied temperatures. The electrochemical model is appropriate for practical RFBs and provides good agreement with experimental data. In addition, a proposed non-ideal electrode model is introduced that accounts for higher voltage losses at low flow rates. Semi-quantitative operation strategies and electrode design guidelines can be obtained from the model. We found that ohmic losses associated with the electrolyte were dominating our electrode losses, which means operating the cell at higher temperature will reduce electrolyte ohmic losses and viscosity, thus leading to higher system efficiency. Thinner electrodes than the 4.5-mm-thick felt used in this study should reduce ohmic losses as well as pumping losses if the same space velocity is maintained. This electrochemical model can be easily incorporated into system-level and cost models, which will help in system optimization, system control, and pump selection and help avoid potential risks of large scale RFB system development. (C) 2012 The Electrochemical Society. [DOI: 10.1149/2.052212jes] All rights reserved.