Zener voltage of automotive alternator diodes

[Circlotron]

I understand that the rectifier diodes in car alternators are made to avalanche at something like several tens of volts so they can protects themselves against transients in an automotive electrical environment. Does anyone have any figures on what this avalanche voltage might be? I want to see how much voltage I can get out of an alternator (no particular application, just messing around) but don’t want to cook the diodes if they begin to reverse conduct unexpectedly.

[bob91343]

Measure a few.

[Psi]

Usually automotive stuff is rated to handle double the voltage for 1 hour without releasing the magic smoke.
So you should get at least 24V out of it before the diodes kick in.

but YMMV

[Mazo]

I remember voltages in the 30-40V range.YMMV.

[SeanB]

Yes, somewhere between 30 and 60V, depending on just how the process was controlled. Some will do 100V with little issue, though when they do go at that voltage they tend to pop. If you want more reliability simply replace with external 3 phase rectifier block.

[Psi]

Can also use a 24V truck alternator if you want more output voltage headroom