Total amperage pulled...?

[ThxOne Premium Member]

I am getting ready to try something new with my stereo. I am removing the RF DSP and I am going to use my head units full active abilities. I was doing some research on amps, ohms and voltages as well as wattage and here is what is going to go on:

Sub - 2ohm - 34.64v at the terminals - looking for 600w - amp says 800w rms @ 2ohms
Mid - 4ohm - 18v at the terminals - looking for 80w - amp says 100w rms @ 4ohms
Twt - 4ohm - 15.5v at the terminals - looking for 60w - amp says 100w rms @ 4ohms

The calculator I used shows only a total of 25.9 amps. This seems low to me but I have never looked into it before so... does this look right to you all? I am pretty much doing this now with the DSP and my lights do not dim even the slightest. Also, my head units volume will be at what the RF DSP deemed to be the max volume (36 of 40) when I delete the DSP and turn on network mode on the head unit. Kenwood says they are 4v pre-outs.

RF Prime 1200.1D
U.S. Acoustics Barbara Ann
Kenwood eXcelon DMX706S

Click to read more...

 

[Bobbytwonames 5,000+ posts]

So, what is your question?

 

[ThxOne Premium Member]

So, what is your question?

It's obvious.

 

[Boomin_tahoe 5,000+ posts]

69.44

 

[THATpurpleKUSH 5,000+ posts]

Total amperage depends on the efficieny of the amps circuitry and load. Amperage pull will vary depending on frequency due to the impedance and phase curves.

The sub will rise to around 6 ohms on avg so the sub amp should be around 50-60a on music.

The other amp is a current hog class AB so I would say 40-50a.

 

[ThxOne Premium Member]

I thought 26a seemed really low. That online calculator must need a new battery.

 

[Bobbytwonames 5,000+ posts]

It's obvious.

My bad, I'm still learning to read! Especially, when after a Lagunitas or two.

 

[n2audio 5,000+ posts]

Your calculations are current output from the amp. That will be much different than current DRAW from the electrical system as the amps step up voltage significantly in order to deliver high power to the speakers.

1200w rms will require something in the vicinity of 100A from the electrical system (WHEN playing tones at full volume).
If you're playing MUSIC loud, you can cut that in half. If you're playing at moderate volume, probably down in the 30-40a range.
That would be AVERAGE current draw. Actual draw will vary significantly second by second based on the signal.

 

[Boomin_tahoe 5,000+ posts]

To be on the safe side, I would go with a 200-250 amperage alt. Leaving a little bit left over for your cars electrical system while still maintaining your audio electrical. Big 3, if it hasn't been done already, using good quality welding cable 1/0 is the norm.

 

[ThxOne Premium Member]

Your calculations are current output from the amp. That will be much different than current DRAW from the electrical system as the amps step up voltage significantly in order to deliver high power to the speakers.

1200w rms will require something in the vicinity of 100A from the electrical system (WHEN playing tones at full volume).
If you're playing MUSIC loud, you can cut that in half. If you're playing at moderate volume, probably down in the 30-40a range.
That would be AVERAGE current draw. Actual draw will vary significantly second by second based on the signal.

Music loud is where I dwell when I am listening to and from deliveries. I was forced to get a new battery recently and I am deleting parts of my system and replacing other parts. I am going from 7 speakers and a 3-way active front to 5 speakers and a 2-way active front minus the stand alone DSP and will be using the head units DSP powers. Pretty sure my Alpine tweeters are unable to handle the Barbara Ann so they are out and in are my Massive Audio aluminum domes.

Crossovers are gonna be the tough choice. I know what the Silverflutes will play and they don't complain all the way up to 5K and down to 60hz. Since I am going 2-way I am thinking the SF's bandpassed 90-100hz and 4k to 4.5k. The Massive twt's at 4-4.5k and I kn ow my sub will play all the way up to 120hz in the enclosure it's in so crossed over somewhere at the bottom of the SF's, 90-100hz.

Your info makes a massive amount of sense. RF says average current draw is 55amps on music but doesn't say at what ohm load... it does say average so that should be the answer overall. I guess I won't have to worry about current draw so much since my battery is new and my stock alt is 125a. We shall see how this turns out tomorrow.

 

[ThxOne Premium Member]

To be on the safe side, I would go with a 200-250 amperage alt. Leaving a little bit left over for your cars electrical system while still maintaining your audio electrical. Big 3, if it hasn't been done already, using good quality welding cable 1/0 is the norm.

I have done the Big Three/4 with 0awg ofc, will be at 2ohms on the sub and 4ohms on the other 4 speakers.

 

[Slo_Ride 5,000+ posts]

My bad, I'm still learning to read! Especially, when after a Lagunitas or two.

Is that like some messican ****. God are you all related? ******* eww. Explains the retard.

 

[Bobbytwonames 5,000+ posts]

Is that like some messican ****. God are you all related? ******* eww. Explains the retard.

Joke bro. Lagunitas is real beer, not the water everybody else drinks. Chill the FO.

 

[ThxOne Premium Member]

I used to deliver craft beer in Ohio and Lagunitas was one of the major brands I delivered. IPA, Lil Sumpin' Sumpin and Maximus were/are my favorite Lagunitas beer.

Here are a few pics. The first one is of a small chunk of what I delivered and the second was of my first day delivering on my own. They gave me a bunch of kegs to break me in lol.

 

[wew lad 5,000+ posts]

You don't need a HO alt for that level of power unless your cars stock alternator is absolute garbage and puts out <50a.