The galvanostat used by Fleischmann and Pons was found to be at the edge of stability and would certainly have caused current fluctuations as a result of cell voltage fluctuations. This has been confirmed theoretically and by experiment. However, the fluctuations do not affect the calculation of the power going into the cell sufficiently to account for the excess heat claims; in the present work, power errors resulting from this effect were less than 0.001%.