My engine, 00 buick regal with 99 lesabre pulley and 95 bonn alt, 905k6 belt, I was driving in the rain after I had put my newly installed uim and the hedlights, wipers, radio and ipod charger wee all running and it just dropped down to about 8v from 14v and wouldnt go up, after a moment it went back up. Problem yes, Answers? Thank you

yea something isnt right... Just those few things shouldnt draw that kind of power. If you dont start your car for a few days will the battery go dead?

This is the first time ive driven in rain since I changed the uim and it was always fine before

is something grounding out possibly.

Ok, the ground on the block had no space after the swap so I bolted it to the cyl head, the belt isnt tight due to the tensioner and alt difference, it stays charged but then this happened in the rain.

Sounds like you need to get a slightly smaller belt, that should fix the tightness problem.

and the rain made the belt slip on the alt pulley?

How tight is the belt? Can you move it easy? The tensioner should be in about the center of it'* travel. If it'* near the end of it'* travel then it will be loose and water on the belt will make it slip, could be at the harmonic balancer or at the alternator.

It wont take a smaller belt, I have no idea why but it will not.

Is it possible your tensioner is getting weak?