In message , Stuffed
writes
That would be a clever trick. ;-) Unless there is some form of electronics
regulating the output the open circuit voltage should be very much higher
than that. Have you measured the AC voltage direct across the transformer
- ie the input to the rectifier?

I seem to recall my cheap n nasty charger puts out around 12v when not
connected to a battery, but I've seen it reach 17v when charging a failing
battery after 12 hours or so. Which I don't think was good for the battery
but at least it was an old and tired one.

What was the shape of the 12.06V though? The DVM was probably struggling
to realise it was DC, try putting a large-ish electrolytic cap' across
it to smooth it out and measure again.
--
Bill