Challenge 31, what should be the output?

[DobbelB]

I was using this circuit to see the voltage of the battery. The voltage of the solution in the simulator shows 6V. But when I test my own batteries and capacitors, all combinations show only around 4.5V.

Is there something wrong with my components, the spring in the top of the capacitor doesn’t lay flat and is pulling the upper arm slightly off-center too.

[DobbelB]

A later puzzle solved the issue.
Tapping the capacitator changes it, knocking on the table works even better.

I also noticed you get more accurate readings if you start the capacitor at a too high voltage and it’s moving down.

The batteries are around 6.5 V