the graph below shows the cell's on-load terminal voltage and temperature for the latest 5200 hours of operation (ie. seven months, since Mar 5th)
(click image to enlarge, use browser Back btn to return)
the cell-stack (2 cells in series) has been under continuous load by a very low-powered LED flasher circuit since the cell was constructed on Feb 17th (ie. 7.5 months continuous operation, so far)
the trend of the on-load terminal voltage shows a slight increase since the start of the experiment whilst the trend of the ambient temperature has decreased over the same period, showing a net charge effect is occurring on the cell stack
to compare the self-sustaining action of these cells with conventional cell behaviour, see the post "Comparison test using NiMH cell"
since the average terminal voltage has slightly increased whilst the average ambient temperature has decreased, it appears that the self-sustaining behaviour is not directly temperature-related and therefore neither is the system gaining its external energy just from ambient heat
the ambient temperature is approx. 20 degC; the mean on-load terminal voltage of this type #2 cell-stack is approx 1.2V