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uncommon power issues


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thegage 
Member - Posts: 27
Member spacespace
Joined: February 15, 2008
Posted: July 26, 2008 at 4:34 PM / IP Logged  

Ok, so I recently invested in a hk802sx amplifier and two Hk15X2 subwoofers.

I have some questions on some things before I put all of this in my car. This is my first install of this magnatude and I dont really want to burn my car to the ground.uncommon power issues -- posted image.

The issue:

I will be running the 15's at .5 ohms stereo to the amplifier, heres what that will look like in amps.

500W RMS x 2 @ 4 Ohms Stereo / .8 = 104.166667 amperes

800W RMS x 2 @ 2 Ohms Stereo / .8 = 166.666667 amperes
1400W RMS x 2 @ 1 Ohm Stereo / .8 = 291.666667 amperes
2200W RMS x 2 @ 0.5 Ohm Stereo / .8 = 458.333333 amperes
4400W RMS x 1 @ 1 Ohm Bridged / .8 = 458.333333 amperes< =text/> vbmenu_register("postmenu_2345163", true);

So...1/0 gauge wire is rated for 350amps of current draw safely. And my amperage draw will surpass the power rated for one run of 1/0 gauge wires so ill need to run two.

I will be running one battery in the front and another in the back. So... Will I HAVE to run two runs of 1/0 gauge wire from the front battery to the back? Or just from the back battery to the amplifier?

Also since my amplifier only allows the input of one power wire how will I disperse the amperage draw? Run two 1/0 gauge wires from the back battery to a bussbar hooked up to the amp, fused by a 250amp fuse on each run of wire?

As I mentioned before I have never done an install this big so any help or CONSTRUCTIVE CRITICISM will be greatly appreciated. uncommon power issues -- posted image.

megaman 
Copper - Posts: 385
Copper spacespace
Joined: June 24, 2008
Location: Montana, United States
Posted: July 26, 2008 at 5:47 PM / IP Logged  

First thing is that your amp draw equation is almost correct.  You have to take into account the efficiency of the amplifier.

since MA Audio gives NO information about their amps online, then we have to take the worst case scenario.  Worst case, it's a A/B amp so it's approximately 60% efficient.

4400watts/.6 = 7300watts/14.4v = 506amps draw.

Best case scenario its a Class D amp and approx. 80% efficient:

4400watts/.8 = 5500watts/14.4v = 382amps draw.

My big question is what are their power output based on?  There is no listing as to what input voltage yeilds 2200watts /channel.

DYohn 
Moderator - Posts: 10,741
Moderator spaceThis member has made a donation to the12volt.com. Click here for more info.spaceThis member has been recognized as an authority in Electrical Theory. Click here for more info.spaceThis member has been recognized as an authority in Mobile Audio and Video. Click here for more info.spacespace
Joined: April 22, 2003
Location: Arizona, United States
Posted: July 26, 2008 at 5:48 PM / IP Logged  
First of all, those MA amplifiers will not put out the kind of power they list, so you will probably need less current than you think.  But more importantly, if you are putting in a 450 amp system, where are you going to get that power?  How many alternators are you installing?
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thegage 
Member - Posts: 27
Member spacespace
Joined: February 15, 2008
Posted: July 26, 2008 at 6:13 PM / IP Logged  

I have a 180amp alt currently. and big 3 upgraded with 1/0 gauge. And I do believe the amp is a class A/B (which sucks)

I hooked up one of the subs to the amp at 1ohm bridged and it was popping a 200amp circut breaker in about 30 seconds at 3/4 volume on the deck and with the gain barely up.

Any idea on how I can spread out all this amperage draw?

audiocableguy 
Copper - Posts: 630
Copper spacespace
Joined: January 27, 2003
Location: Idaho, United States
Posted: July 26, 2008 at 6:16 PM / IP Logged  
Since Audiobahn is no more, has MA taken over the over-rated, meaningless spec, ebay special title?
I continue to beat my head seeing people running amps below 1 ohm.
My amp overheats, it goes into protection, my electrical system is fried... and can't figure out why. Run that MA amp at less than 1 ohm and see which one of the three happens first.
If that amp could put out anywhere near the amount of claimed power wouldn't you think they would make it possible to connect that big of wire?
thegage 
Member - Posts: 27
Member spacespace
Joined: February 15, 2008
Posted: July 26, 2008 at 6:17 PM / IP Logged  

Also the problem I noticed with the amplifier is that in order for it to really work efficently I need to achieve some very high voltage, and Im not sure exactly what I can do about that.

I am only hitting about 13 volts at the amplifier currently, but it was just a trial using 4 gauge wire(about 12 feet long) with a 200amp circut breaker.

thegage 
Member - Posts: 27
Member spacespace
Joined: February 15, 2008
Posted: July 26, 2008 at 6:25 PM / IP Logged  

audiocableguy wrote:
Since Audiobahn is no more, has MA taken over the over-rated, meaningless spec, ebay special title?
I continue to beat my head seeing people running amps below 1 ohm.
My amp overheats, it goes into protection, my electrical system is fried... and can't figure out why. Run that MA amp at less than 1 ohm and see which one of the three happens first.
If that amp could put out anywhere near the amount of claimed power wouldn't you think they would make it possible to connect that big of wire?

Indeed.

I think they also need to replace that RMS title with Peak.

DYohn 
Moderator - Posts: 10,741
Moderator spaceThis member has made a donation to the12volt.com. Click here for more info.spaceThis member has been recognized as an authority in Electrical Theory. Click here for more info.spaceThis member has been recognized as an authority in Mobile Audio and Video. Click here for more info.spacespace
Joined: April 22, 2003
Location: Arizona, United States
Posted: July 26, 2008 at 7:14 PM / IP Logged  

MA Audio is a Taiwanese company that began life as Mobile Authority.  They were selling crap long before Audiobling ever hit the scene.  :)

So you have a 180 amp alternator and a system potentially capable of 500 amp draw?  I smell problems.  You need to be able to supply at least the total current draw of your system PLUS the requirements of the vehicle from your alternator.   You probably need 500 or 600 total amp capacity from an alternator array.  Lots of money layout ahead for you, I'm afraid, if you really want to run this setup.  Let me know if you are serious and I can recommend a company who can build your multiple-alternator array.  Expect it to cost in the neighborhood of $2K, plus the mods to your engine that you'll have to do to make it work.  You may need to discard your air conditioner if the vehicle has one..

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i am an idiot 
Platinum - Posts: 13,667
Platinum spaceThis member consistently provides reliable informationspace
Joined: September 21, 2006
Location: Louisiana, United States
Posted: July 26, 2008 at 8:14 PM / IP Logged  

When figuring current draw you used Class D efficiency numbers. 

thegage 
Member - Posts: 27
Member spacespace
Joined: February 15, 2008
Posted: July 27, 2008 at 12:36 AM / IP Logged  

Yes I did use class D numbers as a refernece. I am still unsure of the class that the amp is.

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