Voltage Issues in Classic


Spyder_1974

CarAudio.com Newbie
Apr 10, 2021
2
0
Canada
Hello so basically I have a on my 1974 Pontiac my issues include:

- Alternator whine higher frequency only comes in through my rear speakers
When I unplug my rcas the alternator wine stops not sure if this indicates anything.

- bumps from sub when breaking

-220a power basterds alternator does not keep the voltage to the rear battery (I have two) and the alt is brand new
between the front of the car and the rear when playing bass it shuts off from low voltage
unless if it is fully charged then you have about 20 min of playtime while driving.
while the car is running 14.4v at the front battery and never see over 13 at the rear as soon as you pull the voltage it drops to close to 11.8 and soon runs out of battery at the rear.
is this because I have 0 gauge CCA instead of ofc the wire has to be run about 25ft because the car is a boat.

My system includes:
all 0 gauge wire
220 amp power bastards alternator
2k skar audio amp
skar zvx 18
And rear Rockford Fosgate speakers that have the alternator wine are powered off of another amp in the trunk mtx amp
 

Kickstand

CarAudio.com Well Known
Jan 1, 2021
474
124
Maple Ridge
What kind of Battery is in the front and the back?
How is the back battery wired?
From the from the front battery, from the alt?
Is there an isolator ?
The second battery is obviously not charging
I would assume its not wired in right
 

SlugButter

CarAudio.com Veteran
Nov 5, 2019
941
324
arizona
Both of these problems could be bad grounding issues. This sounds like what happened to me when I did my first system. Low voltage to the amps and engine whine in my truck was all caused by bad grounds. Had to fix battery grounds and amplifier grounds both, and run my rca and speaker wires on the opposite side of the vehicle as power wires. That fixed my problem.
 

Spyder_1974

CarAudio.com Newbie
Apr 10, 2021
2
0
Canada
  • Thread Starter Thread Starter
  • #4
What kind of Battery is in the front and the back?
How is the back battery wired?
From the from the front battery, from the alt?
Is there an isolator ?
The second battery is obviously not charging
I would assume its not wired in right
I'll have to check brand but they are both 1100cca batteries relatively new have them wired together in parallel one straight wire from front battery to rear than rear battery is grounded to the car body the alternator power wire goes straight to the front battery connected with the wire that heads to the trunk.
I have tried running my rcas opposite from my power wire no difference in alternator whine my grounds look to be all clean but I'll try to maybe relocate them to see if it makes a difference on anything.
I did try a inline isolator on the rcas made no difference in whine. have not experimented with any other isolator
 

MattinMO

Senior VIP Member
Dec 31, 2017
1,138
328
St.louis, MO
Replace every ground you can find. I've had several classic cars and have had issues like this and 9/10 a bad ground has something to do with it
 

Kickstand

CarAudio.com Well Known
Jan 1, 2021
474
124
Maple Ridge
I was talking about an isolator on the second battery.
Because your running to the front battery first it's basically hogging the charge which is probably why your back battery keeps dying.
The first time I tried to set up a dual battery system I did the same thing and had the same results.
You have a couple options, use an isolator.
Run the line to your second battery directly from the alt (fused of course)
All of this however is putting more strain on your alt.
Honestly, on 2000 watts with a 220 amp alt you can probably get away without the second battery
If its not already I do suggest using an AGM Battery though. XSPower, Northstar, even Optima.
AS for your grounding issue
Here is a write up I did a while back on how to find a proper ground
Sorry about the pictures I was new here at the time and wasn't sure how to post them but if you click on the links they are all there
https://www.caraudio.com/threads/how-to-find-a-ground-for-your-amp.607223/
 

Create an account or login to comment

You must be a member in order to leave a comment

Create account

Create an account on our community. It's easy!

Log in

Already have an account? Log in here.


Users Who Are Viewing This Thread (Users: 0, Guests: 2)



Latest posts

Most posts - Past 30 days

Latest classifieds