I finally enchanted my sword with Life Steal and for some reason I now have infinite charge on the sword.

I'm not sure whether it's the enchantment itself, or combination of it with Fiery Soul Trap.

Anyway because of this glitch I now have a sword better than Ebony Blade interms of Life Steal.

Just want it to share it with you all.

I think absorb life enchantments benefit from Destruction skill/perks. That might be why it never needs recharging.

Do you have 100% destruction fortifcations?

I do too.

That would be why. The cost in charges per use decreases with the cost of your Destruction spells, so if you have zero spell cost you also have zero charge cost. If you have mixed effects (say, Paralyze+Absorb Health) it's a bit more complex; I think the way it works is that it keys off of the more expensive effect, but I'm not sure.