Voltage Drops

[jmc916]

Hello,

So I decided to test my voltage yesterday after dealing with dimming lights and the engine feeling sluggish sometimes while sitting idle with my music playing at loud volume levels.

Here's what I have hooked up in my 2003 Nissan Altima right now. It's my old equipment that I'm using until I can afford all new equipment:

- Amp: Kenwood KAC-729, running at 150 watts RMS x 2 at 2 ohms

- Subs: 2 Sony XS-L151P5

- Wiring: Raptor 4 AWG Power & Ground (I think this may be my problem??)

- Alternator is about 2 years old, I had shop put it in after stock alternator went bad

- Battery is Enegergizer brand I bought from Costco about 2 years ago

- NO big 3 has been done

Here's the voltage readings I was getting with my multimeter at the amp:

- 12.86 with car off and no music

- 14.13 with car on and no music

- Once I started turning the volume up to loud levels the voltage would drop down from anywhere between 13 volts to low 12 volts. When the voltage would drop you could feel it in the engine, it felt sluggish to say the least... If I kept turning the volume up, the amp would eventually go into protect mode I'm assuming because it wasn't getting enough voltage at that point.

I also hooked the multimeter up to the battery terminals while the car was off and got normal readings 12.5-12.8 and when I turned the car on with no music I also got normal reading there 13.8-14.8

I don't understand why that little Kenwood KAC-729 amp would put such a strain on my electrical system. I would hate to see what a "real" amp would do to it. :-)

Since I'm using cheap power and ground wires (Raptor) I wanted to start by replacing those with some high quality brand name cables. Maybe that's the cause of this problem???

Any input or help is appreciated! Thanks!

[jmc916]

OK, here's what I did today.

I tested the voltage at the battery terminals with the car ON and OFF with NO MUSIC. Both of those tests showed normal voltage readings.

Then, I tested at the battery terminals with the car ON with loud music and the voltage levels still gave good results. For this test I was using the 4 AWG Raptor cable and the amp would go into protect mode once I got to a high volume level.

Next, I tested at the battery terminals with the car ON with loud music, but this time I was using the 8 AWG Rockford Fosgate power cable. The voltage levels still were at good levels. The amp would still cut out once I got to a high volume level, but I was able to turn the volume up louder than when I was using the 4 AWG Raptor cable before the amp would go into protect mode.

So to sum it up; the voltage readings at the battery terminals looked good whether the car was ON or OFF with loud music playing or not. So it looks like my battery and amp are OK.

Am I just experiencing clipping???
My gain on the amp is definitely not turned up.

[DroppedSdime]

Raptor isnt really that bad, but i doubt its the issue. You might have a ground issue, check all your grounds.

[jmc916]

Right now I'm grounded with the 4 AWG Raptor cable to one of the seat belt bolts under the rear seat.

Sine the problem gets worse the higher the volume gets, would it still be a grounding problem? Or would I see the problem ever at lower volume levels?

Thanks!

[infamous360]

Right now I'm grounded with the 4 AWG Raptor cable to one of the seat belt bolts under the rear seat.

Sine the problem gets worse the higher the volume gets, would it still be a grounding problem? Or would I see the problem ever at lower volume levels?

Thanks!

Seat bolts are usually TERRIBLE grounds. Ground to the frame if you can. Be sure to scrape off any paint etc...

[jmc916]

Right now I'm grounded with the 4 AWG Raptor cable to one of the seat belt bolts under the rear seat.

Sine the problem gets worse the higher the volume gets, would it still be a grounding problem? Or would I see the problem ever at lower volume levels?

Thanks!

Seat bolts are usually TERRIBLE grounds. Ground to the frame if you can. Be sure to scrape off any paint etc...

OK, I'll try to find a better spot to ground. You wouldn't happen to know off the top of your head a good place on a 2003 Nissan Altima? :-D