Headlights dimming with under 400W of power

[Mast0rMason_]

Oh, that reading from the ground terminal is does not sound correct.  You need to educate yourself on how to use a multimeter.  Its your best friend in car audio issues.

This is how you use your multimeter to see if you are getting a good reading with 12 v.

Set your multimeter to 12v dc, not AC.

probe the red one on the battery positive on your amplifier, and the black one on your negative one.  Should read 12v.

Ask a mate to start your car and keep the probes there to see the voltage drop.   If it drops to a few volts then you have to check your grounding points on the amp, head unit and test it again.

If the voltage still drops to a few volts then its time you replaced your battery.  Hope this helps you out mate.

Tested it again at work, one cca says 380a the other days 270a so the batteries powerful enough. Voltage drops to around 13.85 now when they bass hits and around 13.7 with the fans on max and the bass hitting and the headlights. Could slight corrosion on the positive on the amp on the battery effect this too then? I’ve only just got my driving license back from a medical condition and my car was sat for 9 months. With the engine turned off battery reads around 12.8ish or something.

negative terminal to engine is fine with the ohms couldn’t find a part on the chassis without paint under the hood.

 

[DRBOOM]

Hey mate,

Thanks for the update.  I suggest you disconnect your battery ground, then the positive one too, and get some sand paper and sand both terminals then wipe with dust cloth then connect your terminals back but do the positive one first, then the negative one last. 

I overlooked that issue as well,  maybe that should fix your issue after you clean it up and apply some light grease over the terminals to avoid water / corrosion issues in future. Also check that your battery connections are tight as well.

Cheers from Australia!

 

[Mast0rMason_]

Hey mate,

Thanks for the update.  I suggest you disconnect your battery ground, then the positive one too, and get some sand paper and sand both terminals then wipe with dust cloth then connect your terminals back but do the positive one first, then the negative one last. 

I overlooked that issue as well,  maybe that should fix your issue after you clean it up and apply some light grease over the terminals to avoid water / corrosion issues in future. Also check that your battery connections are tight as well.

Cheers from Australia!

Thank you, I’ll keep you posted if it fixes it, the terminals are dry so their could be corrosion on them! I’ll do it either in a min or tomorrow on my lunch break 

sanded down the terminals and everything and voltage still drops the same  

 

[DRBOOM]

OK, this is my suggestion to you now. 

• Upgrade your chassis ground to engine;
  
• Borrow a car battery from a friend, and give it a run in your car;  if the problem persists then;
  
• check your cars head light point, could be poor ground / corrosion to the head light connections itself or its not properly fitted to the car headlight mechanism;
  
• buy / another set of HID replacement lights /  try them out first to see if the problem persists;
  
• try out another subwoofer amplifier to see if the problem still persists;
  
• Are you sure you checked your car head unit, ground, Car battery ground, amplifier ground to see they are properly secured and tight?
  

Let us know how you go mate!

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