This fine?

[jbizzle 5,000+ posts]

I'm at work atm.. so I decided to check what my voltage drop was..

My front battery (Optima YT) Wouldn't drop below 14v at pretty much full tilt @ 2k rpm.

The back batt (Deka G31) was dropping to mid 13's sometimes high 12's. (readings were taken at the amp)

Even at idle the gauge didn't drop when the voltage was actually dropping..

Just wondering if thats normal...

Click to read more...

 

[jrwalte 10+ year member]

Sounds like a bad ground (or too small). The current is having a hard time flowing from the alt to the back amp and that results in voltage dropping. Some voltage drop is expected, but that much indicates an issue. How are you grounded in the back?

You aren't running an isolator, right?

 

[jbizzle 5,000+ posts]

No isolator, and its grounded directly to the frame

 

[jrwalte 10+ year member]

It looks like you may be running more wattage than a frame ground may be able to support (every car will be different). If you have any extra 1/0 wire I'd try a run from the engine block/alt to the rear bat and see if it helps. If so, install it.

 

[jbizzle 5,000+ posts]

I already have 1 run going to the back of + wire, are you talking about a - run?

I ran into too many problems with a - run to the back, so I grounded in the back.

 

[jrwalte 10+ year member]

Yes. I was talking about a - run. Problems with installing it or problems with it working as a ground - induced noise or something?

 

[jbizzle 5,000+ posts]

Amp wouldn't turn off, subs were pulsating..

The ground was directly from the front batt.

 

[jrwalte 10+ year member]

Odd. Never heard of a ground causing an amp not to shut off - not that it couldn't be possible. If you still have that run of - wire I'd test it from the engine block to see if it helps. You can test it with and without the frame ground.

If you haven't, you should check all the ground points and make sure they are tight and have no corrosion.

 

[jbizzle 5,000+ posts]

All grounds are fine and are tight as can be..

My ground is a little long though

I used an old ground I had that installers used (over a year ago)

 

[jrwalte 10+ year member]

Maybe you should try moving it closer. And I took it for granted that the - run from bat to frame is 1/0. That correct?

 

[jbizzle 5,000+ posts]

But I cleaned it real well, took off the paint, so its shiny metal

 

[jbizzle 5,000+ posts]

Yes, everything is 1/0, KNU KLM

 

[terra 5,000+ posts]

It looks like you may be running more wattage than a frame ground may be able to support (every car will be different). If you have any extra 1/0 wire I'd try a run from the engine block/alt to the rear bat and see if it helps. If so, install it.

not sure what you mean by that...I'm running 6k on a frame ground.

 

[MasterOfAllBass 10+ year member]

i could be wrong but this is my 2 cents worth. Maybe his back batt is not charging well... from lack of a good alt charge. I could be wrong

 

[jrwalte 10+ year member]

not sure what you mean by that...I'm running 6k on a frame ground.

I'm stating that not all cars have the same frame. While 6k RMS may be fine on one car's frame, it won't be on anothers. It could also just be the existing ground spot he is using.