Can I ugrade to a second sub on my 50A Alternator?

[RSDXzec 10+ year member]

My car was made in 1984 so the stock alternator is 50Amps and there would be hardly any other draw coming from it other than the sound system.

My system consists of

4x45Wrms amplified speakers

350Wrms subwoofer

so i'm currently on 530W rms.

I'd like to get a second subwoofer which would be another 350W rms and I think 880W rms is a bit much for this old low power alternator. The easiest option for me would be to get a second sub and run them both with the same amp I have now and they will each be at half power, still giving me a 3db improvement. Anyone got any idea as to how much rms I should draw from this alternator?

Then I could get an amp powerful enough to power both of them but keep the gains/volume knob down so that they only use x amount of watts rms.

I will be looking at prices on better alternators soon, but I'd like to see how far I can get on the stock alt. I may also consider doing the big 3 upgrade on this alt to make sure i don't lose any power along the way.

Cheers.

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[chillin 10+ year member]

What are you driving?

 

[audiobaun 5,000+ posts]

Ohh man..50amps??? Id deff, do the big 3,and look into some old school amps that use 12 ga power supply,Like some of the Alpine Duo-B amps,ect.Run 4ohms if you can..You might be ok at 2ohms, but I deff wouldnt try 1ohms with your supply.be safe at 4ohms, and a non power hunger older amplifier..//content.invisioncic.com/y282845/emoticons/crap.gif.7f4dd41e3e9b23fbd170a1ee6f65cecc.gif

 

[audiobaun 5,000+ posts]

What are you driving?

^^^^ you in a Geo Metro or something like that??Excellent for the Gas price Hikes

 

[RSDXzec 10+ year member]

What are you driving?

right now I'm in a 1984 Holden astra... waiting until I can afford a toyota supra so this will do until then.

Ohh man..50amps??? Id deff, do the big 3,and look into some old school amps that use 12 ga power supply,Like some of the Alpine Duo-B amps,ect.Run 4ohms if you can..You might be ok at 2ohms, but I deff wouldnt try 1ohms with your supply.be safe at 4ohms, and a non power hunger older amplifier..//content.invisioncic.com/y282845/emoticons/crap.gif.7f4dd41e3e9b23fbd170a1ee6f65cecc.gif

I'm running 2 ohms now, is there a problem with that? I have 8ga power wires to it as well.

I was going to buy an audiopipe amplifier, most likely the 1000wrms mono amp and set the gains down so I won't exceed 700w rms. That would be at one ohm.

My subs are dual 4 ohm voice coil, so if i had two I would be at 1 ohm. I could have them at 4 ohms as well but i would need a bigger amp, then i'd go for the audiopipe 1500wrms amplifier so I can run it at 4 ohms. What's the difference on my alternator with a 4 ohm load as opposed to a 1 ohm load?

Since I=V/R I'm guessing a higher resistance reduces the current necessary but i'd like to confirm this.

And what ga wire would you recommend for the big 3 on a 50A alt?

Cheers.

edit: the amp I'm looking at if I go 4 ohms supplies 600w rms so each sub will be underpowered by 50w rms but i doubt i'll tell the difference.

http://www.audiopipe.com/products/amplifiers/ap/ap-15001d.html

 

[audiobaun 5,000+ posts]

When you run at 1ohms load..it will **** your battery/power down pretty quick.You really need some power to generate to stay stable at that ohms load and the amp runs hott all the time,4ohms will draw less current, and run much cooler,yet, will not be as low as 2/1ohms.I mean your alt will be working pretty hard if not go out pretty soon/getting hott trying to keep up with the constant supply needed.Yet, you can try it, as stated before..You want to see how far you can go??Might as well and try, and see what happens???I dont recommend it, but its your vehicle, and your system,ive given you my opinion,in which was asked of.Hope all ends well

 

[winkychevelle 10+ year member]

Ohh man..50amps??? Id deff, do the big 3,and look into some old school amps that use 12 ga power supply,Like some of the Alpine Duo-B amps,ect.Run 4ohms if you can..You might be ok at 2ohms, but I deff wouldnt try 1ohms with your supply.be safe at 4ohms, and a non power hunger older amplifier..//content.invisioncic.com/y282845/emoticons/crap.gif.7f4dd41e3e9b23fbd170a1ee6f65cecc.gif

really with the ohms = efficiency thing

a 500w class d mono that is designed to put out 500w at 2 ohm will have roughly 50 amps of draw

a 500w class d mono that is designed to put out 500w at 1 ohm will have roughly 50 amps of draw granted it will be more efficient and draw less power at 2ohm it will be putting out substantially less roughly 250w

higher ohm loads dont mean less voltage draw when comparing amps mayber when looking at one amp running 1,2,4ohm but then you are looking at three different levels of power as well

as long as the amp is designed to run the needed ohm load u will be fine. old class ab's running 1oh monos will draw double sometimes triple the amperage as a comparable class d

it gets even worse when you start comparing old school high current amps to the newer class d amps

to the op i recommend a new alt before anything. most cars can be rewound for more amperage for less than a comparable new alt. the big 3 and a good starter batt can go along way but the alt need to be bigger at least 150amp anything less is a waste of money unless it cant be built to that much amperage then the biggest you can get will be better than now

 

[MECHMAN 10+ year member]

You really need more charging power before you add more load. The alternator will be working at 100% output all the time and will not last very long.

You may be able to adapt a unit that is readily available in your country that will allow you 100a or more and save you the expense until you get your new car.