Thread: Voltage drop from alternator

Ok so I am not a mechanic by any means. I have recently has issues with my car dying due to battery drain. I first assumed that it was the alternator and replaced it. Still not getting enough charge to the battery. I've had the battery checked out, and both the new and old alternator are only putting out 12v or less while the car is running. I'm pretty much at a dead end as to where my knowledge is and I wanted to see if anyone could help me with ideas to figure this dilemma out. I appreciate all the help and I'm sorry if this is a repost of any other problems just like it.

If the battery is dead, the alt wont do its job.

Where are you taking your measurements from?

I've had oreillys charge the battery about three times as well as putting it on the charger at home too after it gets drained. I'm using a multimeter and testing the output from the alternator at the battery terminals with the car running. Also using the ground on the battery and putting the positive lead to the connection on the fuse box under the hood. Getting the same voltage in both places. I don't see it being a bad alternator seeing as I've had them tested, so it was a bit of a waste that I bought a new one, but, oh well.

What I'm thinking is that I'm getting some resistance in the circuit somewhere....problem is, I know jack about the wiring and need some help.

I haven't added anything to the car, no. Actually this all seemed to start after a bad rain storm in which my car suddenly began leaking inside under the passenger dash onto the floor board. I've since sealed around the cowel on the car preventing water from going into the air box beside the drain on the firewall. I've teste it by running a water hose full blast on that area, which it would leak before, but now t doesn't.

Anyways, there is the potential that maybe something in that area got shorted out, there is a fuse box in the glove compartment and I've checked the fuses with no luck.

I'll keep trying with the meter to find variations in the voltage.

Oh and it takes roughly 20-30 minutes driving after charging the battery although I'm probably not charging it completely as my charger is old and doesn't give you any idea how much charge your battery has.

I am gonna try that, I just had both alts tested and they're both good, confirming my suspicion. So, I'll give residing the hot wire from the alt to the fuse panel and see how that works, but something tells me it's more complex than that, because that's just my luck lol

Ok so, and sorry for my lack of knowledge, I need to runs 6 gauge wire from the alternator to the fuse box, correct? And can you explain what a fusable link is exactly?

Awesome! Thanks! I'll give this a shot and see how it goes.

Hm, once the car is on, I think the ground switches to the engine/transmission. You may want to check that ground - it could be loose or something.

Thank you cerick and ejouie, I've done what you guys said and now I'm getting 14V output. Working good now! Thanks for all the help everyone, couldn't have done without all of your help!