This is very simple mod that add change to silent moons enchant.
-Fix silent moons enchant bug in vanilla(This fix is included in Unofficial Skyrim Patch).
-Change Silent moons enchant's property to "While the moons are out, absorb <mag> points of health." 
-Change Visual enchantment effect to red,
 And when it attacks, an effect is the same as vampire's absorb magic.
-Longer gauge than general absorb health.

Sorry, I'm poor at English. I hope this is transmitted correctly.