Alternator belt tension

With the alternator problems that many of us are plagued with, I would at least like to get alternator tension right. What is the correct tension?

Thanks

 

[rdomeck]

Tight is tight and too tight is broke!

 

About 10mm (maybe a touch less) deflection if you press hard with a finger in the middle of the belt, always worked for me.

 

Duh, that is what I am trying to avoid.

Quoting rdomeck:
Tight is tight and too tight is broke!

 

Thanks, good to have some reference point.

Quoting Justin_Cosgrove:
About 10mm (maybe a touch less) deflection if you press hard with a finger in the middle of the belt, always worked for me.