Why is my voltage drop so awful?

[hatedonmostly 5,000+ posts]

Front battery? It's grounded at the factory ground points in the engine bay which is the front fender and the engine block.

How do I measure resistance of a wire? Set dmm to ohm and put one prong on each side of the wire I'm assuming?

 

[jco1385 5,000+ posts]

yep

 

[hatedonmostly 5,000+ posts]

Also, when I measured at the distro it was at the battery (input) side. Checked that a while back, figured the the distro could be one of the first things causing the issue...

 

[hatedonmostly 5,000+ posts]

Put the one probe on the wire down by the battery, and the other on the amp since that's as far as I could get it to reach.

So even passing through the distro, I only got resistance bouncing between 0.0 and 0.1...

 

[Stalin-ohaulic]

Since you STILL aren't getting it, let me break it down for you:
I asked:

You replied:

Yet, here you are on CA.com, complaining about CA.com.

... and I explained why... YOU are the one too dense to get it, just like you're too dense to fix your voltage problem.

 

[hatedonmostly 5,000+ posts]

... and I explained why... YOU are the one too dense to get it, just like you're too dense to fix your voltage problem.

Then tell me, all knowing one, what I am doing wrong? I've tried grounding both the amps and battery to the body and the frame, and there is no resistance between the battery and the amp, which is where the problem is occurring.

Let me guess, "you need to do the big three in 1/0" just like all the other sackriders are saying? Sure, that might help slightly, but not even near enough to make up for a 1v loss.

 

[Stalin-ohaulic]

Then tell me, all knowing one, what I am doing wrong? I've tried grounding both the amps and battery to the body and the frame, and there is no resistance between the battery and the amp, which is where the problem is occurring.
Let me guess, "you need to do the big three in 1/0" just like all the other sackriders are saying? Sure, that might help slightly, but not even near enough to make up for a 1v loss.

I had multiple opportunities to suggest that yet did not... why? We are worried about the difference in potential between the rear batt and the amp that is right next to it. How would changing something totally unrelated help? It won't. You have high resistance between the amp and the back battery. You can say you don't all day long, but that voltage drop proves you wrong. You have a bad solder joint or crimp on a ring terminal or too long of a run. I haven't seen your install but it's right there. It can't be anything else. This is common sense of course....

If I had to guess I'd say it is the soldered ring terminals. They provide superior connections most of the time, but when it slips a little as it's almost cool, you get a cold solder joint and it works but under a heavy draw provides lots of resistance.

 

[hatedonmostly 5,000+ posts]

I had multiple opportunities to suggest that yet did not... why? We are worried about the difference in potential between the rear batt and the amp that is right next to it. How would changing something totally unrelated help? It won't. You have high resistance between the amp and the back battery. You can say you don't all day long, but that voltage drop proves you wrong. You have a bad solder joint or crimp on a ring terminal or too long of a run. I haven't seen your install but it's right there. It can't be anything else. This is common sense of course....
If I had to guess I'd say it is the soldered ring terminals. They provide superior connections most of the time, but when it slips a little as it's almost cool, you get a cold solder joint and it works but under a heavy draw provides lots of resistance.

I appreciate your help man. I was under the impression that the voltage should be lower at the amp since that is what is drawing the current. I will try this tomorrow and we will see what happens...

 

[jco1385 5,000+ posts]

so did you re-do that terminal? if so, did it fix it?

 

[hatedonmostly 5,000+ posts]

About to take it out to test...

 

[hatedonmostly 5,000+ posts]

Didn't help at all. //content.invisioncic.com/y282845/emoticons/frown.gif.a3531fa0534503350665a1e957861287.gif

When idling and nothing playing, the front battery was reading different than the rear battery and the amp, which were reading the same. When playing full tilt the amp was dropping to 11.5 (it's hotter today, than before) and the rear battery was dropping to 12.7. There's still a difference between the two, although there shouldn't be.

 

[jco1385 5,000+ posts]

did you re-solder it or whatever? is the amp grounded to the battery or to the chassis? gotta ask... is everything tight? battery/chassis/amp connections?

 

[hatedonmostly 5,000+ posts]

did you re-solder it or whatever? is the amp grounded to the battery or to the chassis? gotta ask... is everything tight? battery/chassis/amp connections?

Yes, resoldered it; kept it hot and made sure not to move it while it was cooling.

Amp is grounded to the chassis, from that chassis ground there is a jumper to the frame, from that frame ground there is a jumper to the battery. Kinda retarded, but I did the best with what wire I had... :/

Everything is very tight.

My alt is a aftermarket replacement for these trucks, that's supposed to be OEM spec. Should I swap my original back on?

 

[jco1385 5,000+ posts]

all points of ground are sanded to bare metal? could it be a bad fuse?

 

[hatedonmostly 5,000+ posts]

Yes sir. I doubt it...