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140amps Alt enough?

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Old Nov 19, 2008 | 08:42 AM
  #11  
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Motor on,50hz tone to the sub until the amp clip, 13.1v at batt 10.5 at amp
That really doesn't sit well with me. That means the amp is drawing MORE than 140 amps. Unlikely. I would be suspect that the alt is on its last legs, or does a lousy job at making power at low rpm. Rev the engine and see how much that changes the voltage drop. Maybe a smaller pulley is all you need.

A bigger fuse is does not reduce resistance like that.

All a second battery is going to do is put a bandaid over a bullet hole.
Old Nov 19, 2008 | 10:58 AM
  #12  
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Originally Posted by Sasha
If the fusing and wiring is correct, and you still get big voltage drops, look into testing that battery, as it may be bad, and not charging fully, unless it has very small capacity, and not able to buffer your system properly.
Even if the voltage drop is only at the amp, at the batt terminals there's not a huge drop
Old Nov 19, 2008 | 03:23 PM
  #13  
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Even if the voltage drop is only at the amp, at the batt terminals there's not a huge drop
So you are saying at the battery terms the voltage looks good, and at the amp it is bad?
Old Nov 19, 2008 | 05:14 PM
  #14  
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Originally Posted by BIGEVIL
So you are saying at the battery terms the voltage looks good, and at the amp it is bad?
well when the amp clipped, at the batt terminals I got 13.1v, so the alt was still doing its job, the real prob was at the amp with only 10.5v

2.6v drop for a 16 feet 4ga run
Old Nov 19, 2008 | 06:54 PM
  #15  
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its too long man i have the same problem lol
Old Nov 19, 2008 | 08:40 PM
  #16  
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I used to have those same long runs. Simplest way to fix it is with a distro block. Now i happen to be running mine from the aux. batt, but who cares, if you run big 1/0 or something to a block (even 15 ft) then the drop is pretty small compared to puny 4 awg.

Then run 4 awg from the block to the amps, like maybe 12" or 18". The drop on that length of run is very, very small.
Old Nov 19, 2008 | 10:25 PM
  #17  
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Ok you both convince me, now i need to find the damn thing at a reasonable price... is the copper/strand better in welding cable?
Old Nov 29, 2008 | 10:53 PM
  #18  
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Originally Posted by John__Taylor
I used to have those same long runs. Simplest way to fix it is with a distro block. Now i happen to be running mine from the aux. batt, but who cares, if you run big 1/0 or something to a block (even 15 ft) then the drop is pretty small compared to puny 4 awg.

Then run 4 awg from the block to the amps, like maybe 12" or 18". The drop on that length of run is very, very small.
Today I installed the 1/0 and the 1/0 to 4awg block. WOW this is what i call a cable! But, I still get the same voltage drop... So now i am thinking that my ground's not good. I am currently grounded to the jack rack near the wheel (it looks like it's soldered to the chassis...). Tomorrow ill try another ground and see if it help.
Old Nov 30, 2008 | 02:51 AM
  #19  
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Crummy grounds can cause a lot of problems. Make sure you take some emery, scotchbrite, sandpaper, anything really and clean off any paint or rustproofing where you are bolting your ground.

You ARE bolting it down right? You know, get a big *** ring terminal and crimp it to the wire.

No Possible way you should be having a 2.5v drop in wire that size. You should be getting almost the same voltage at the back as near the front.

i was reading 14.2 or 14.3 at the front, and 14.1 or 14.2 at the back. I would say a 15 foot run.

Test the voltage with nothing running (except the engine) at the front, then the rear. I bet you its the same right?

Get back to us. You went and did the wire so I'd like to help you fix the problem.

Oh, I had an 02 once also, has the front of your hood started to rust away yet?

John
Old Nov 30, 2008 | 08:05 AM
  #20  
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Originally Posted by John__Taylor
Oh, I had an 02 once also, has the front of your hood started to rust away yet?

John
LOL yeah i had the hood replaced under warranty in 04! I didn't have the same luck with the trunk lid...

For the current ground, it's clean, i used sandpaper to get to the metal and i used a metal screw to hold the terminal in place...



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