Alternator??????

 

Bronze Member
Username: Dustin3

Tigard, Or U.S.

Post Number: 84
Registered: Oct-05
hey,

i have a new battery that is called Exide 60 (i got it from baxter) and i have a jeep cherokee 1989. I have 2 12 inch sub and a total of 400 watts rms going to each sub.

what kind of alternator would i need so my headlights dont flicker and so i keep the power flowing well. how many amps of power from alternaor
 

Bronze Member
Username: Crazydude

Post Number: 50
Registered: Nov-05
http://www.the12volt.com/info/recwirsz.asp


http://www.excessiveamperage.com
 

Bronze Member
Username: Dustin3

Tigard, Or U.S.

Post Number: 85
Registered: Oct-05
yes, i already read that. that just says about the kind of alternators their are. i need to know how many amps i would need for my 2 12's. My stock one is like 60 amps or sumthin.
 

Silver Member
Username: Fandim

Reno, Nevada United State...

Post Number: 423
Registered: Jun-05
Amps x Volts = Watts. So.. watts / volts = Amps.

You figure it out. :-)
 

Bronze Member
Username: Dustin3

Tigard, Or U.S.

Post Number: 86
Registered: Oct-05
r u talkin about the watts that my amplifier is putting out? i dunno the volts i have an audiobahn a8002t amp
 

Silver Member
Username: Tdbdadrummer

Post Number: 663
Registered: Aug-05
Amps = Your fuse rating which on that amp is 2 30A fuses.

Volts = 12.5 I believe, which is standard battery voltage.

Watts = RMS rating of your amp in watts.

So...800W/12.5V = 64A.

You'll need an additional 64A to EFFECTIVELY power that amp. Honestly, it's actually quite beastly for a and Audiobahn lower end amp. I have it, it dims the heck out of my interior lights lol. I'm getting 180A alternator for it and my A4002T, so yea, you'll need some extra power.
 

Bronze Member
Username: Dustin3

Tigard, Or U.S.

Post Number: 88
Registered: Oct-05
wut r u running off of it tyler??

yea, i was thinking a 180 amp alt.
 

Bronze Member
Username: Dustin3

Tigard, Or U.S.

Post Number: 89
Registered: Oct-05
your a8002t.
 

Silver Member
Username: Tdbdadrummer

Post Number: 669
Registered: Aug-05
Soon, after Xmas lol, my total amperage consumption should be like near 100A. Not including any lighting I may add.

That's 10A for my HU: Kenwood KDC-X589
That's 40A for component speakers' amp: Audiobahn A4002T
That's 60A for subwoofers' amp: Audiobahn A8000T

That is all give or take a few amps of consumption, but it's near 100A. I believe my car comes stock with a 105A alternator, and the car's stock electrical system takes 60% of that's 63A from basic stock stuff. 100A for aftermarket gear, so I'll be pushing 163A hehe. Leaves me enough room for some moderate lighting equipment and such. But Nate's alts are supposed to be kind of beastly, so I'll trust that it can take the abuse, and I don't generally "bump" as they say going around on a standard car run!
 

Bronze Member
Username: Dustin3

Tigard, Or U.S.

Post Number: 90
Registered: Oct-05
how do you find how many amps for a HU and for sub's amp?
 

Silver Member
Username: Tdbdadrummer

Post Number: 670
Registered: Aug-05
By checking the fuses on the amp (you can tell what they are) they stick out and say on them, for example, 20A. There is one on the back of your HU as well.
 

Silver Member
Username: Fandim

Reno, Nevada United State...

Post Number: 428
Registered: Jun-05
The fuses is the point where the amp will eventually pop due to overload..you should not be running at what the fuses say..

A class D is roughly 80% efficient. So figure, if you're running a 1,000 watt amplifier, you will actually be drawing around 1,250 watts. (1250 x .8 = 1000 rms). Most amps (non-regulated, like the audiobahn), give their RMS rating at 14.4 or so volts. So, in the case of a Class D amp, putting out a true 1,000 watts RMS, you would be drawing about 86 amps of current.

Thing about fuses is, you shouldnt be drawing their max, because running at their absolute max current ( or in a lot of cases, even near it ) for a period of time, will blow the amp.

(Say you have a 100 amp fuse. At 105 amps of current, it might not blow for like 3 minutes.. at 200, might blow in like 10 seconds etc)
 

Bronze Member
Username: Dustin3

Tigard, Or U.S.

Post Number: 92
Registered: Oct-05
how would you be drawing around 86 amps of current???

so what does this mean for my audiobahn a8002t amp? and for my alternator situation...

also, what do you mean by 100 amp fuse. is that like an amp putting out 100 watts rms?

please help
 

Bronze Member
Username: Dustin3

Tigard, Or U.S.

Post Number: 93
Registered: Oct-05
the guy above said my audiobahn is 12.5 volts and you said it is 14.4? who is right?
 

Silver Member
Username: Tdbdadrummer

Post Number: 674
Registered: Aug-05
Seth is right. I questioned whether it was 14.4V or 12.5V. It's my mistake, I apologize.
 

Bronze Member
Username: Dustin3

Tigard, Or U.S.

Post Number: 94
Registered: Oct-05
so how would you be drawing around 86 amps of current as seth stated?
 

Silver Member
Username: Tdbdadrummer

Post Number: 675
Registered: Aug-05
You wouldn't. You'd be drawing less, like me, as we're both running 800W RMS.
 

Silver Member
Username: Fandim

Reno, Nevada United State...

Post Number: 429
Registered: Jun-05
My example was for an amp that was 1000 watts RMS just for easy math and to explain the formula you'd use, etc.
 

96bigdogg
Unregistered guest
does anyone know if a 200-250 amp alternator will damage stock electrical componets ?
 

Bronze Member
Username: Gezyon

Havelock, NC United States

Post Number: 20
Registered: Nov-05
Well about the lights dimming, I had the same problem in my vehicle, before I upgraded some stuff. I did not get a aftermarket alternator, I still am running the factory alternator and believe me before I did everything, the lights would dim like crazy.

How I fixed the problem, and now they dont dim at all, was:

1. I upgraded all my wires, ones from the alternator to ground and battery, and from the battery to the amp and ground.

2. I installed a deep cycle optimum battery in the rear inline with my battery up front.

3. I also have a Capacitor inline with my amp to help with the initial power drain that it pulls.

4. I have a digital readout on the battery in the rear, so while I am playing the stereo I can watch the voltage drop on the system. Before I added the extra battery the subs and amp was making the voltage drop well below 11.6 VDC which would make my lights dim and the amp was not getting enough voltage to even try to push the subs, now aftering doing everything I did, my voltage stays above 13.5 even when the system is hitting hard! Now my amp is getting the power it needs and my lights dont dim.

That is all I did. I am running a 1500 Mono Class D amp pushing 2 12" subs.

I dont know if this helps out with anything, but some info can be useful.

I know doing this on my system made a dramatic difference in how my system sounded and now my ligths dont even twitch.
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