280amp alternator with dimming head lights

[dgaf 10+ year member]

First of all go to a shop that specializes in alternators and let them test it, dont go to auto dumb or advanced stupid parts and see if it actually gives out the amps it says it would, i had a problem with my becouse i brought an rebuilt one and it was only giving 80 amps (i checked it at this onre place in chicago), use a different ground, that doesnt look like a good ground to me and that distro block aint good too. Triple check ur big 3 again. Also is your battery a dual purpose? If it is there is no possible way you could be dimming.

It's an Optima yellow top 34/78, no idea what dual purpose is.

That's a good idea, I'll swing by the alternator shop that installed it, and see if they can meter it.

 

[mac208x 10+ year member]

I just looked up in the interstate catalog that i got a the shop, and your battery is infect a dual purpose with means its both a starting and a deep cycle (Deep discharge designed)

It's an Optima yellow top 34/78, no idea what dual purpose is.That's a good idea, I'll swing by the alternator shop that installed it, and see if they can meter it.

 

[mac208x 10+ year member]

Oh also i forgot to mention this, Your belt on the alternator cant be too tight it has to go in at least 1/3 of an inch when you press on it.

 

[dgaf 10+ year member]

couldn't make it to the alt shop today, had a buncha stuff to do around the house, plus the weather is terrible.

will try and troubleshoot more tomorrow, weather permitting, will post results...

 

[Sub Woofin 10+ year member]

Have ya seen how close the power and grounds are on some amps? Especially when people use 1/0 adapters. His are fine.

yea, but still

Those are both ground wires, all my colors are wacky in there.The bolt that's holding the silver 1/0 is the bolt that the seat belt used to be attached to, it's the same sheet metal as the other place I had there that you can see in the picture. I had never used it, I did it then noticed the seat belt bolt and used that.

I'll give it a shot changing it, but it's the same metal, just one big bolt holding it down instead of four small self rappers and a washer.

you dont get any unwanted noise?

 

[dgaf 10+ year member]

^ Nothing I was getting before I had it hooked up.

(when iPhone/iPod is charging, it gets some noise, I just don't charge the device I'm using for music, and everything is clean)

 

[dgaf 10+ year member]

Today I finally had some time to mess around with my voltage problem again.

(In case you didn't read everything in this thread, I'm dropping to 11.8 volts when subs hit)

I know everyone said it was the ground, but, again, the ground was solid before, and I even ran the 4ga from battery negative to ground block as well as a 1/0 from ground block to factory bolt. Anyways, I'm not able to get to the 1/0 ran to the factory bolt, it's behind the box, which is way too big to move or remove with one person. However, I was able to get to the ground block. On the ground block I had 2 more spaces available for 4ga inputs. So I ran two more 4ga wires from ground block to frame. It's a nice spot, under the carpet, brushed away the paint, it's two more solid, good grounds.

Still dropping to 11.8.

I don't know how I didn't think of this earlier, I guess I just assumed it wasn't an issue, but, the more I think about it, this could be the problem. When the alternator shop installed my alternator, they didn't have the top mounting bracket for the alt. The original factory bracket wouldn't fit this DC Engineering alt. So, the shop just put in the two bottom bolts to hold the alternator in. I asked DC about it, they said it's fine, I asked the shop, they said it's fine.

So, the two top bolts that are usually attached to the bracket, which is attached to the engine, are not being used.

Think this could be the issue with the alternator not being properly grounded?

Should I run 1/0 from those bolts to negative, or from bolts to frame\chassis?

 

[dgaf 10+ year member]

up

 

[tc300 10+ year member]

Run wires to the alt Bolt holes.....? I have nota clue but it DOESNT sound right!! Lol.

 

[dgaf 10+ year member]

^ yea, but i'm thinking it may not be getting a good ground with just the bottom two mounting feet holding it on. can't really see what their attached to to see if it's making a solid connection to the engine block or what. i'm thinking about going from those bolts to the same points as my big 3 grounds?

 

[grandam888 10+ year member]

its not a bad idea to ground the alternator via the bolt holes. and one bolt should be fine, and going to the same place as other grounds is fine also.

let us know what happens