"Home-Brewed" Battery + and - Terminal Blocks Finished Photos Added

A zener is a special series of diodes, mostly used for voltage regulation. They work like a normal diode in forward (conducting) but if hooked "reverse" as "not conducting" they will conduct "backwards" at their rated voltage. This is called "avalanche region."

Anyhow, What is going on here, is that if the pair wired up as Dave suggested conducts, the Zener will only let the conducted voltage "rise" to the voltage rating of the zener, IE 60V