Voltage Drops

[digitalbass]

I have checked my wiring to make sure I was running the correct ohm load to the amp. However, I can not seem to stop breaking my fuses on the power wire in the engine bay. The fuses seem to break when I have the volume of the HU up to my max listening volume. They are Rockford Fosgate 60amp maxi fuses. The song that they break on has very powerful low bass. I have read that it may be happening because the music is trying to pull a large amount of power to hit these notes.

Is there any kind of textbook explaination?

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[faulkton 5,000+ posts]

what is the fuse ratings on your amps? Its not more than 60 amps for all your amplifiers combined is it? Start with the obvious. What about your gains? Are you sure they are set correctly?

 

[bjfish11 5,000+ posts]

what amp are you running?

 

[RandyJ 10+ year member]

The textbook answer would be this.

You amplifier is drawing more current for a longer period of time than the inline fuse on the main power wire can support.

Solution? As stated, go with the obvious and simple stuff first. Check the rating of the amplifier itself. If it is rated at 90A and you only have a 60A on the inline, then the problem is obvious. The answer is still simple though, the amplifier is purely drawing more current than theh fuse will allow.

 

[digitalbass]

I'm running an MA Audio HK1398 2-channel class A/B amp. There are (4) 30amp fuses on the amp itself. Would I need to match the total fuse ratings of the amp to the fuse on the power wire?

As for the gain setting on the amp, it is set a little below the half mark. The bass boost was set slightly higher than the lowest setting. I tend to keep the LPF around 70Hz - 110Hz.

Would breaking all of these power wire fuses damage any part of the amp or subs? How can low voltage issues be damaging to amps and subs?

 

[bjfish11 5,000+ posts]

well thats your problem, Yes you need to match the fuse size, so you need to upgrade that 60 amp to a 120 amp fuse.

 

[digitalbass]

How much damage could voltage drops do to the amp? Wouldn't the protect mode of the amp prevent any damage from voltage drops and voltage surges? Also, could voltage drops and voltage surges cause any damage to the subs?

 

[knukonceptz 10+ year member]

Blowing a fuse in your case is not going to hurt anything. A fuse blows to protect other parts from damage. In this case, your protecting the wire since the amp can and wants more power. Upgrade to a 120A fuse.

A few things cause voltage drop, one is bass, the other known as loss, is from resistance of the cable @ x amount of Amps. Using poor wiring or the wrong gauge cable, creates a bigger loss. Deep bass notes increase the severity of these drops/loss. Under voltage protect is listed by most amp maufactures in there protection circuit. However, that usually ends up causing most amps' failure. Lower voltage makes the power supply work harder to keep up with the outputs demand for power. Over working the power supply is what causes most failures (that and runing an amp at an impedance it was not designed for)

Use a digital volt meter to see what your voltage is at the amp. With it off you should see 14V, @ full volume you'll see dips into 13V, lower then 12.6 is not good

 

[johnecon2001 5,000+ posts]

I wouldn't just go and "upgrade" the fuse. You need to look at your power wire first to ensure that upping the amperage of the fuse won't light your car on fire.

Going up to a 120-150a fuse would be a great idea for you... IF you're running 4awg wire or higher. If you are running anything under that, stay at around and 80a fuse. But in this case the answer is pretty clear, you NEED to be running the larger wire WITH the larger fuse in it.

 

[murphy54]

it may be a electrycal redundacy effect ...if them aren't in good shape(electrical charge that keeps on staying there ,if certain tehnical prerequisits aren't meet -eventualy leads to overloading electrical circuits)

 

[digitalbass]

I have read the fuse section of http://www.bcae1.com and the maximum fuse size for the 4 awg power wire is 125 amps. I need to figure out what is the safest size fuse to use because I don't want to max the wires capabilities.

 

[helotaxi 5,000+ posts]

There is a margin of safety built into that chart on BCAE. 120A is exactly what you need.

They don't make a MAXI fuse that size, they are only rated up to 100A, you will need a new fuse holder and fuse. Either a MIDI or ANL fuse are what you are looking for.

 

[digitalbass]

I am not figuring the fuse size based on the MA Audio amp that I currently have. I will be getting a much more efficient class D mono amp. How would a 100 amp maxi fuse work with a more efficient amp using 4 awg wire?

 

[helotaxi 5,000+ posts]

Assuming that the new amp doesn't draw more than 100A continuously, it will work fine.

 

[digitalbass]

How would I be able to tell if the amp draws that much current? Is there a particular stat that shows how much current the amp is drawing?