(I have no experience of electrostatic analysis - so I don't know what this problem is.)Concerning the change to the SI system, I thought I made clear why. We need a way to display any kind of results. The problem was eminent when support for electrostatics was added. ...
I have expressed my opinion about scaling of units in:
https://forum.freecad.org/viewtopic.php?f=18&t=69423
The results should be presented in the "Unit System" chosen.
So if you have chosen "Standard", the output should be in terms of mm/kg/s/degree.
(At this point I have to say that you should not use the word degree - you should use the actual degree unit, e.g. Kelvin or Celsius.)
The "Unit System" data then specifies the units of the results
If your displacements are very small, say, the "Calculate and Plot" function can be used to scale the values; the scale is then in your control.
"SI is THE standard almost everyone uses/understands" - try telling the Americans.
When I was doing FEA, my models were in mms.
The volt has units:
volt = kg .m^2 /(A . sec^3)
A - ampere - is a base unit (not derived.)
As a matter of interest, if you were performing an electrostatic analysis would the model be defined in metres?
You need to add the ampere to the lists in "Unit System" panel and make all the other systems consistent. Including Building Euro's units.
USER DEFINED UNIT SYSTEM:
Perhaps there needs to be an entry in "Unit System" for user defined. The only requirement is that the system be consistent.
The FEA uses the values that it is supplied, e.g. it doesn't know the units of length.
If the units are consistent, then any forces on the model will generate stresses in the consistent unit.
PROBLEMS WITH THE DISPLAY OF THE SCALE:
1 - try g format for the numbers.
2 - put numbers on the left of the scale.
3 - allow the scale to be translated.