Is it normal for battery voltage to drop this much?

  • 4
    Participant count
  • Participants list

Josh Dubin

CarAudio.com Newbie
6
0
So I'm having an issue with my system. At high volumes, the voltage at my battery is dropping from ~14V (with no music playing) - ~12.5V. Is this expected for an 1100W amp? If not, would this indicate that my battery or alternator is failing to keep up? I got my battery tested and it says it's fine but I'm not 100% sure that that test applies when you have an 1100 watt amp.  

Thanks,

Josh

 
So you are using a multi-meter at the battery terminals while playing music where the amp wiring is coming from?

Remember all Lead acids usually have a resting voltage of around 12-13V...AGM batteries can rest at around 13 or just under.  The Alternator is what brings the system up above 14v.

 
So you are using a multi-meter at the battery terminals while playing music where the amp wiring is coming from?

Remember all Lead acids usually have a resting voltage of around 12-13V...AGM batteries can rest at around 13 or just under.  The Alternator is what brings the system up above 14v.
Well I've measured the voltage at the battery terminals and at my amp, with and without music, with the car on and off. With the car on, no music, voltage at battery terminals is about 14V. Once I start playing loud music, voltage drops to as low as low 12's, at battery terminals. Is this type of drop normal,  or is there an issue? And would this issue be the alternator ?

 
You have an issue. What amp is it? What car/alternator current rating do you have? What subs and ohm rating being used?


You have an issue. What amp is it? What car/alternator current rating do you have? What subs and ohm rating being used?
It's the alpine mrx m110. 1100 watts. I have an infiniti g37. I believe it's rated at 150 amps. I have a single dvc 4ohm sub, wired to 2 ohms.

If my voltage is dropping significantly when the sub is hitting hard, would that imply my alternator is on its way out?

 
Last edited by a moderator:
im not familiar with that vehicle...but 150A alt. should have no problem with that amp, i doubt your seeing full power from it also...my amps in my jeep are capable of 2000 rms and i have 160A alt. never had a problem with voltage even before upgrading electrical (big 3, dual batteries).....throw a decent AGM under the hood and do the big 3....see what that does.....also check/clean all your grounds

 
Last edited by a moderator:
Activity
No one is currently typing a reply...
Old Thread: Please note, there have been no replies in this thread for over 3 years!
Content in this thread may no longer be relevant.
Perhaps it would be better to start a new thread instead.

Similar threads

What the ****? Are you trying to put ohm's law into very complicated verbiage?
6
862
I like the way these look. But whatever I do it has to be top post. My battery is on the driver side and right beside the air filter housing. So...
6
621
If your audio system constantly draws more amperage than your alt produces, it will drain your battery, to the point of the battery needing to be...
14
1K

About this thread

Josh Dubin

CarAudio.com Newbie
Thread starter
Josh Dubin
Joined
Location
Start date
Participants
Who Replied
Replies
6
Views
1,169
Last reply date
Last reply from
YourNameHere
DD451980-D607-41AB-B69C-6745AAE4B848.jpeg

SlugButter

    Mar 28, 2024
  • 0
  • 0
F98C6D78-7734-4659-9FCA-34969BDDC56A.jpeg

SlugButter

    Mar 28, 2024
  • 0
  • 0

Latest topics

Top