help with electrical 2000w rms 2003 gmc envoy

[devin171moto]

Im currrently planning an uprade from my 500 w rms rockford p1 enclosure to something like 2 sundown SA- 12's or similar. in a 2003 gmc envoy
the sa's would be 1500 rms together and figuring in 125 w rms x 4 for components i would be at 2000w rms. (2500 w draw accounting for efficency, d class amps)
my question is.... do i need an alternator?? orr no? stock alt on gmc envoy is 150 amps
and i was either gonna go with 1 xs power agm d3400
or 1 Duracell Ultra Platinum AGM Battery with Dual Terminals for BCI Group 34/78 SLI to replace stock battery,and Duracell Ultra BCI Group 27M Deep Cycle Marine & RV Battery as a secondary. what do you guys think? im kinda lost here. have no idea where to go
amperage draw for 2500w from battery is 180A.

[miniSQ]

Probably the first thing i would do is have the current state of the electrical system tested and see if everything is working correctly. I don't know that you need a second battery. Maybe just get a new main battery that is a starter/deep cycle design if you plan on lots of listening with the vehicle off. The 150amp alternator should be up to the task if it is working properly, but no reason not to consider replacing it since it is almost 20 years old i assume?

[devin171moto]

yeah alt has never been replaced to my knowledge. i can check its amp output tommorow.
would you go for the xs power d3400 agm 80ah or something like a more mass produced red top or generic starting/cycle battery. (d3400 from xs is 360 bucks at 80 ah) and the generic brands at autozone are like 200 bucks for 55a:20 hours (but idk how those handle at like 150 amp draw)

[miniSQ]

I have had zero problems with my Optima Yellow top which is going on year 5, but if i suggested that to you people would immediately chime in and say that optima's are terrible and don't last. Maybe look at the Odyssey AGM's? Not sure if they have deep cycle that is also a starter battery.

[Theslaking]

XS are sweet. I have also had zero issues with my Duralast agm and I abuse that battery by never charging and rarely driving the car it's in.

Don't replace anything until you know you have a problem. Check your wiring and contact points, upgrade if necessary. Fire up your system. Your lights will immediately tell you if you need to upgrade.

[syc0path]

amperage draw for 2500w from battery is 180A.

That's assuming the electrical system maintains 13.9V under full draw of the amps. Simply put, it won't. At 12.5V, the amps would draw 200A. I would figure for at least that much when sizing your power cable and fusing.

Whether or not the stock electrical system can keep up depends on your listening habits and typical driving routes. If u are a dedicated bass-head and like to pound as often as possible in stop-and-go traffic, u will quickly run out of power. If u only crank it for a few minutes on the freeway, then u should be ok. But even then I would expect a lot of headlight dimming.

[dumdum]

That's assuming the electrical system maintains 13.9V under full draw of the amps. Simply put, it won't. At 12.5V, the amps would draw 200A. I would figure for at least that much when sizing your power cable and fusing.

Whether or not the stock electrical system can keep up depends on your listening habits and typical driving routes. If u are a dedicated bass-head and like to pound as often as possible in stop-and-go traffic, u will quickly run out of power. If u only crank it for a few minutes on the freeway, then u should be ok. But even then I would expect a lot of headlight dimming.

Not quite... if the amps are regulated to make the same power at lower voltages, most amps aren’t, so the current draw is effectively set, the power output drops, so the amps won’t draw any more

plus in reality you won’t ever draw near to 100a, and more likely <50a most of the time due to impedence rise, not playing sine waves flat out at all frequencys etc, so for such a system as this 150a of alternator is ample, I’ve run more off a lesser alt and it was fine

even when pounding as you put it, the average current draw will be sub 100a

[syc0path]

W/o a voltage reading and a clamp, we're just estimating what the draw will be. Using the same method I used to estimate the draw of his amps, my amps draw 150A. My car has a 125A alt, so estimated max draw is 150A / 125A = 120% of alt capacity. I get significant dimming when I crank the bass, which I generally do on the freeway at night for about 10 mins or so at at time. Lol... I actually had a guy start to pull over in front of me becuz he thought I was a cop behind him, due to the way my headlights were flashing!

The OP will be running 200A / 150A = 125% of alt capacity, so I would expect him to have slightly more dimming than I do.

U can argue that those amperage draw numbers are inaccurate, but I think the comparison is what's important. If I see that much dimming on the freeway, then it will only get worse in stop-and-go traffic.

[ckirocz28]

W/o a voltage reading and a clamp, we're just estimating what the draw will be. Using the same method I used to estimate the draw of his amps, my amps draw 150A. My car has a 125A alt, so estimated max draw is 150A / 125A = 120% of alt capacity. I get significant dimming when I crank the bass, which I generally do on the freeway at night for about 10 mins or so at at time. Lol... I actually had a guy start to pull over in front of me becuz he thought I was a cop behind him, due to the way my headlights were flashing!

The OP will be running 200A / 150A = 125% of alt capacity, so I would expect him to have slightly more dimming than I do.

U can argue that those amperage draw numbers are inaccurate, but I think the comparison is what's important. If I see that much dimming on the freeway, then it will only get worse in stop-and-go traffic.

You have to also consider what kind of amperage the car's electrical system draws. I saw somewhere that the alternators are sized to output 60% of their rating to run the factory electrical system. In any case, an aftermarket high output alternator is usually a good choice for a high wattage audio system.