Alternator and Battery Question

[ascitiesburn69 10+ year member]

I planned to get 2 sdc2.5 12's and run them off about 1500rms. But unfortunately I went to scrapin the coast and heard numerous systems that were 148+ and now I want nothing else but to be that loud. So I was thinking the only thing holding me back from pushing 4000-5000watts is my alternator and batteries. If I were to get a mechman 220 or 250amp alternator, would it be possible to push anywhere between 3500-5000wrms with the right amount of d3100s or kinetik 2400s or possibly deka 9a31s? I'll take any suggestions on types and amount of batteries needed.

And if anyone would like to give 3500-5000wrms amp suggestions that are on the "cheaper" side, it would be appreciated. I'd be running two 12" copper coil hdc3s OR two 12" DC lvl4 xl's.

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[91Chevy 10+ year member]

Realistically, 2800W is the max a 250A alternator (@ 80% Efficiency) can handle. If you have a large bank of batteries that would help, but you'd still have to listen to it for moderately short periods of time.

 

[ascitiesburn69 10+ year member]

hmm maybe I need to look into a 350amp alternator. That should handle 4k watts easily with 2 d3100s or so?

 

[tommale420]

hmm maybe I need to look into a 350amp alternator. That should handle 4k watts easily with 2 d3100s or so?

if your already gonna snag a 250, might as well spring for the 350 for safety reasons. could save u a bit of money in the long run and also in case of upgrades down the road. been there, done that

 

[terra 5,000+ posts]

If you want daily use, don't go bigger than 250amp. That will be fine to support a big system.

 

[tommale420]

If you want daily use, don't go bigger than 250amp. That will be fine to support a big system.

im sure your right, but curious, would a 350 damage anything on daily?

 

[MakeshiftAudio 10+ year member]

So, if I'm reading it right, a 250A alt with 2 D3100s will support a 4kW amp just fine?

 

[terra 5,000+ posts]

im sure your right, but curious, would a 350 damage anything on daily?

No but look at the at idle output of a 350 amp alt. What looks better for daily?

So, if I'm reading it right, a 250A alt with 2 D3100s will support a 4kW amp just fine?

After rise and voltage loss? Absolutely.

a 4kw amp will do just fine on a 250 Mechman alt and 2 D3100's.

 

[tommale420]

No but look at the at idle output of a 350 amp alt. What looks better for daily?

wont a simple touch of the gas cure that? as well as the other reasons i gave good enough to get the 350?

After rise and voltage loss? Absolutely.

a 4kw amp will do just fine on a 250 Mechman alt and 2 D3100's.

i do agree with this. i ran a 200 amp alt. with big 3 a regular bat under the hood, 2 HC2400s in the rear supporting a memphis 4000 and i didnt see under 13 volts.

 

[terra 5,000+ posts]

wont a simple touch of the gas cure that? as well as the other reasons i gave good enough to get the 350?

After rise and voltage loss? Absolutely.a 4kw amp will do just fine on a 250 Mechman alt and 2 D3100's.

i do agree with this. i ran a 200 amp alt. with big 3 a regular bat under the hood, 2 HC2400s in the rear supporting a memphis 4000 and i didnt see under 13 volts.

At a stop light I drop to 700 rpm. Sure I could sit there and rev it to 1500 to get huge output...but why? The 250 amp is a much better daily application. If for competition, sure just hold it at 1500rpm and get 330 amps from the big alt.

 

[tommale420]

right on. opinions vary. id spring for the 350, but thats me. sorry for the confusion OP

 

[terra 5,000+ posts]

250-daily bumping

350-competition use.

 

[MakeshiftAudio 10+ year member]

See, this confuses me...

The alternator charges at a voltage of about 14.4V with x amps. (Theoretically)

In a case with my setup in which I have 4 runs of 4/0, where I can run some 350A about 20' with .32V drop, will it be pulling the current from the alternator as much as it can until it reaches down to the voltage of the D3100s, which are charged by the alt to 14.4? Will the load be distributed between the batts and the alt, or what?

This confuses me, I'm more of a digital person and RF analog, not generators.

 

[tommale420]

250-daily bumping350-competition use.

you know, u can manually adjust the idle on your car. and also, yours idles at 700, doesnt even a stock idle at around 900 which in this case means there is a 200 difference in idle. would it be that be worth it considering some of the other benefits of having the 350? why didnt steve meades do 4 250s instead of the 350s hes running?

 

[terra 5,000+ posts]

you know, u can manually adjust the idle on your car. and also, yours idles at 700, doesnt even a stock idle at around 900 which in this case means there is a 200 difference in idle. would it be that be worth it considering some of the other benefits of having the 350? why didnt steve meades do 4 250s instead of the 350s hes running?

You'd have to talk to Meade but I don't think he is running production units. Plus he is powering gigantic amounts of power. Everytime I've talked to an alt company they recommend me a 250 amp unit for daily driver because of output at idle. Sure, get the 350 and raise your idle speed. Not worth it imo.