280amp alternator with dimming head lights

[dgaf 10+ year member]

i'll try taking the ground from the ground block off the seat belt bolt and back to the sheet metal i had it on originally.

but, do you really think that's what it could be?

it's gunna be a pain in the d!ck to pull all that crap outta there...

 

[dbjunior 10+ year member]

wow try checking the belt a loose or worn belt will slip resulting in poor output from the alt. sometimes you need to add a pulley to give you more contact with your belt

 

[dgaf 10+ year member]

that seems to make a lotta sense to me, but, belt seems tight, i dunno much about that, how tight the belt should be, but, i put my fingers behind it and pulled, it's tight on there, it barely flexed up

 

[ColterDC 10+ year member]

that seems to make a lotta sense to me, but, belt seems tight, i dunno much about that, how tight the belt should be, but, i put my fingers behind it and pulled, it's tight on there, it barely flexed up

Yeah you're alt and belt are fine.

It really sounds like a grounding problem. Did you try a new ground (You don't really need to disconnect everything if you have a few spare pieces of 0 gauge leftover from your install).

Btw... nice documentation on your install. Did you do as someone in your log thread suggested and clean up the big 3 grounds and spray some anti rust over all that bare metal?

 

[ColterDC 10+ year member]

For the most part, the battery is just there to start the car. You can start the car with your batt, then disconnect while the car is running, and the alt will keep the car going.

For the record......don't do that. It would be bad.

Most pre 80 cars were able to do this, but not modern cars.

 

[CHEMMINS 10+ year member]

How did you set your gains? With a scope or dmm? Are you clipping at all?

 

[09civic 5,000+ posts]

How did you set your gains? With a scope or dmm? Are you clipping at all?

i'm sure he is...

 

[dgaf 10+ year member]

Yeah you're alt and belt are fine.
It really sounds like a grounding problem. Did you try a new ground (You don't really need to disconnect everything if you have a few spare pieces of 0 gauge leftover from your install).

Btw... nice documentation on your install. Did you do as someone in your log thread suggested and clean up the big 3 grounds and spray some anti rust over all that bare metal?

thanks, yea, i did, was pretty dumb though, i scooped a can from home depot, clear, sprayed a little on the grass before to make sure it was all good, then i took the connections off, cleaned em all up, put em back on, and sprayed, spray came out brown... someone at home depot had switched the caps, so the brown can had a clear cap and was in the clear section... had to go back to home depot, get a new can, then take the connections back off, sand\brush the paint off... pain in the d!ck... but yea, their done now, look good, the one under the hood i actually drilled out a bigger hole, and put a nut and bolt through, so it's not just a self tapper, looks good...

How did you set your gains? With a scope or dmm? Are you clipping at all?

gains were set just by ear, and then turned down a little more to be safe. robin, (iamamp3pimp on here) set em, he knows what he's doing. i found a guy in town that has an oscilloscope, i'll probably hit him up and see if we can get it tuned in perfect after i fix this voltage issue

 

[ColterDC 10+ year member]

All I know is I've had my F250 running the 1800 rms watt stereo, front and rear dvd screens playing, dragging my 20 ft trailer up a steep canyon road with the A/C or heater on and my son rolling the rear windows up and down with no dimming whatsoever.

This is with the stock 130amp alt, stock battery and no big 3 done.

So either his new alt/battery is defective or he's got a wiring problem.

I feel your frustration though man. I struggled for a long time to figure out the dimming problem on my mustang. You can even check my past posts asking for help on here. But in the end it was a combination of things that took tons of research and help from my Ford mechanic friend to figure it out.

1. Stock alt was showing signs of dying. Got a 250 HO alt, that helped a little.

2. Car was idling to low, had to get the idle up to around 700, instead of the 450 it was at.

3. Cooling fan was going out and causing an extra large draw every time it kicked on.

(I also replaced the throttle body, IAC motor, CAI and filter and serpentine belt. No idea if any of those things had an effect)

So about $700 later and a ton of my time I can actually play my stereo with the A/C and headlights on without any dimming. And I'm running way less watts in that car than you have.

 

[The_Grimy_One 10+ year member]

For the record......don't do that. It would be bad.
Most pre 80 cars were able to do this, but not modern cars.

I was not recommending it, was just trying to prove that the alt does a lot more than just charge the batt.

 

[Devil Tiger 10+ year member]

I would bet that ground is what is causing it. Ground needs to be on the frame of the vehicle, not a seat mount.

 

[Sub Woofin 10+ year member]

I got big 3 done.

i really dont like that distro block you got there. the power and grounds are soo close to each other

 

[CHEMMINS 10+ year member]

i really dont like that distro block you got there. the power and grounds are soo close to each other

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

 

[mac208x 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.

 

[dgaf 10+ year member]

i really dont like that distro block you got there. the power and grounds are soo close to each other

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.