<VV> simple corsa clock question

[Jim Simpson]

One modification you can make that will help the longevity of the clock is
to add a diode across the electrical contacts to suppress the arcing.  Any
common rectifier diode should work.  Just connect it with the "band" end
(the cathode) to the "+" (battery) side and the other end to ground.  This
diode will shunt the reverse current induced by the electromagnet when the
contacts open that would otherwise cause an arc and gradually burn the
contacts.

And yes, the clock runs on the full 12 volts.