No I said 3 cells (4V5) connected to the 5Volt source or 5 cells (7V5) connected to the DCin jack. I also said that for light loads 4 cells might work although you may have 2 problems. The first and obvious is that a batteries voltage decreases with use so at some point the battery is going to approach the point where it is below the required input voltage and that that point might well be above the "dead" cell voltage (.9V to 1V1) and second that even good new cells would be an issue with a heavy load as their terminal voltage will fall far enough to make the power supply unstable. which brings us back to 3 cells on the 5V source or 5 cells on the DCin jack.
Bob