Will my stock civic alternator be ok with 1000rms?

[alexdbest2000 10+ year member]

Alpine MRV-M500 amp (500 rms @ 2 ohm)

MB Quart DSC 4125 (125 rms x4 @ 4 ohm)

-1 gauge wiring going to mono amp and a separate 4 gauge wire going to the 4 channel amp

-Big 3 is done with 1 gauge wiring

-Stock alternator (2004 civic, 70A alternator i think)

-Stock battery

Should i be ok?

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[mylows10 5,000+ posts]

Agm battery or two. One up front. One in back then yes

 

[Kastlez_ 10+ year member]

04 accord batteries Are horrible!

Mine were atleast

Do yourself a favor and put at least one Agm up front

 

[negolien]

70a is pretty small and I have a group 75 battery with about 900 watts with slight dimming at night and our alts are like 110 stock I think. Might think about an alt upgrade since you got the big three already. Will be the easiest fix for you imho.

 

[gstokes]

Alpine MRV-M500 amp (500 rms @ 2 ohm)MB Quart DSC 4125 (125 rms x4 @ 4 ohm)

-1 gauge wiring going to mono amp and a separate 4 gauge wire going to the 4 channel amp

-Big 3 is done with 1 gauge wiring

-Stock alternator (2004 civic, 70A alternator i think)

-Stock battery

Should i be ok?

let's do the math, at full volume the amp would be producing 1000 watts of continuous power, with 70 amps available (if the alternator is producing rated current) and 14V source would only provide 980 potential watts but that's not including voltage drop or any current to recharge the batteries or even run the ignition system and headlights, you might be able to use a maximum of 1/2 of the available current (driving in the daytime and it's not raining) for the head unit amplifier and anything else you have wired up, now with 35 max amps for the stereo and 14 volts potential provides 490 after minimum 2v drop = 420 total power, so i would say probably not, not even close...

 

[negolien]

let's do the math, at full volume the amp would be producing 1000 watts of continuous power, with 70 amps available (if the alternator is producing rated current) and 14V source would only provide 980 potential watts but that's not including voltage drop or any current to recharge the batteries or even run the ignition system and headlights, you might be able to use a maximum of 1/2 of the available current (driving in the daytime and it's not raining) for the head unit amplifier and anything else you have wired up, now with 35 max amps for the stereo and 14 volts potential provides 490 after minimum 2v drop = 420 total power, so i would say probably not, not even close...

Could you supply the math please as far as how do you do those calculations.

 

[gstokes]

Could you supply the math please as far as how do you do those calculations.

absolutely, with 1/0 gauge cable you will still incur almost 1 volt drop in source voltage and running 1 channel in 2~ will cause another drop and you will be left with 12 volts when you started with 14 at the source, you have so many amps to run the entire vehicle plus anything you add to it, like a sound system, it puts a load on the charging system that is more then it can handle so guess what happens next, the lights dim because of the voltage drop, the amplifier ****** it up and left nothing for the headlights so they dimmed.

If the lights aren't on when you put that load on then charging system then something else is dimming, you feel me. Power isn't free and it requires current flow and voltage to produce, if we only got 12 volts left after the pre-determined voltage drops from adding a length of 1/0 gauge and a length of 4 gauge and then another voltage drop for the channel running in 2 ohm and we multiply that x available current that tells us exactly how much power we are going to produce measured in watts, the sound system will probably draw more than 35 amps and you will make more power than i stated but it's only going to get "so" loud because of 2 things, line voltage and available current. You can compensate for the dip in line voltage by adding a battery and/or capacitor and placing it right next to your amplifier ..

Alpine MRV-M500 amp (500 rms @ 2 ohm)

MB Quart DSC 4125 (125 rms x4 @ 4 ohm)

-1 gauge wiring going to mono amp and a separate 4 gauge wire going to the 4 channel amp

-Big 3 is done with 1 gauge wiring

-Stock alternator (2004 civic, 70A alternator i think)

-Stock battery

Should i be ok?

 

[akillj 10+ year member]

Don't forget that amplifiers aren't 100% efficient. Assuming 80% efficiency on just the class D, you're looking at 1250 watts of power consumption from the amp. Or, 86 amps.

We figure this by taking 1000w (amplifier output) divided by it's efficiency (Guessing 80%) which gives us 1250 watts of power consumption.

1000 / .8 = 1250

Or, 86 amps.

1250 / 14.4 = 86

Unless your alternator can supply an extra 86 amps, along with running the car AC/Headlights/Ect then you will get voltage drop, which then means amperage (Current) must rise to compensate. Current = Heat, Heat = popped fuses / burned out amps and electrical system.

A good watch if you want to know what kind of electrical to have:

 

[alexdbest2000 10+ year member]

I used to have a 93 civic back in the day that has a mono amp running at 750rms and there was no dimming whatsoever, why is that? Everything was stock with 4 gauge wiring

 

[negolien]

voltage times alt got it thanks

 

[gstokes]

I used to have a 93 civic back in the day that has a mono amp running at 750rms and there was no dimming whatsoever, why is that? Everything was stock with 4 gauge wiring

could be several reasons, maybe your electrical system was able to handle the extra load, maybe you weren't actually running 750 watts..

 

[bmk6795 10+ year member]

I used to have a 93 civic back in the day that has a mono amp running at 750rms and there was no dimming whatsoever, why is that? Everything was stock with 4 gauge wiring

I've got the same car you do. Mines an 01. The alternative is 70 amps. I think you'll be fine running the amount of power you're running. Big 3 is about all you'll need. I'd look into doing an eld bypass as well. Else wise your voltage will be at 12.5v 90% of the time.

 

[alexdbest2000 10+ year member]

I've got the same car you do. Mines an 01. The alternative is 70 amps. I think you'll be fine running the amount of power you're running. Big 3 is about all you'll need. I'd look into doing an eld bypass as well. Else wise your voltage will be at 12.5v 90% of the time.

Whats your setup if you don't mind me asking?

 

[bmk6795 10+ year member]

Whats your setup if you don't mind me asking?

Right now its a single HDC 3 15 on a ppi bk 1800. Jbl ms62c comps up front on a rf 550.2. Running about 2k watts with big 3, kinetic HC1200 up front and a 75ah C&D in the back. Lowest my voltage drops is 13.5 at idle, but thats playing bass boosted music.

 

[alexdbest2000 10+ year member]

Right now its a single HDC 3 15 on a ppi bk 1800. Jbl ms62c comps up front on a rf 550.2. Running about 2k watts with big 3, kinetic HC1200 up front and a 75ah C&D in the back. Lowest my voltage drops is 13.5 at idle, but thats playing bass boosted music.

Where did you mount your tweets?