Test a Voltage Stabilizer

[Paul-Ernest Levesque <pelevesque@globetrotter.net>]

I have read with a Volt Meter the voltage of the output of a battery charger
it read 14 volt and then pass trough the voltage stabilizer I read 14 volt
again, I thought the voltage stabilizer would reduce the voltage a bit and
keep there. What is the proper way to check that apparatus. Thank you in
advance.
Paul-Ernest