DON'T GET A CAPACITOR! That's truly a trash way to do it on a low level setup. Capacitors are trying to charge up in the dead space between your music's sound. Depending on the music you listen to, you may have very little break for them to charge. Getting the proper size alternator is planning so that you always have enough power to keep your battery charged and your system powered.
Think of it like this. You are driving on a road that is constant hills. You're adding a load (amps/ call it a trailer). Do you want just enough power to get to the top, so when you start to go down hill you can keep it floored so that you can pick up enough extra speed to make it to the top of the next hill (capacitor), OR, do you want a bigger engine, so you can get to the top of any hill at any time with the power you have (proper sized alt and battery). Not to sound like a snob, but unless you have some LARGE setup that has it planned out for capacitors and needs them because you have a vehicle for your stereo, then they are a cheap way to jimmy rig it because you don't want to spend the money to do it right.

Lets figure this out. 450 watts + 500 watts = 950 watts. Use ohms law to divide 950 watts by voltage (I know you 2013 runs lower than it, but 14.4 volts for the standard number). 950 /14.4 = 65.9 amps. You didn't say if those were peak numbers or RMS, but this should tell you how to figure it out. Your vehicle with everything running is about 100-120 amps, (there are ways and videos on this, if you really want to figure it out).

If you listen to your stereo with your truck off, then we have 950/12 volts = 79 amps, (if you do sit and listen with it not running, then you would want to know how many amp hours your going to pull off your battery). Most people don't do this for very long, so I'll move on, but just giving you the basics so you can figure it out for yourself.


When buying an alternator there are two numbers that matter; output at idle, and rpms for max output. Your alternator has a power curve (usually straight), just like an engine. The difference between those cheap alternators and a quality alt, is how early does that curve kick in. You can buy a 300 amp alternator off ebay for $100, and it will do about 80 amps or less at idle (probably less than your factory), and won't get max output until over 3,000 RPMs, (think about where your RPMS are when you drive, you will never see max charge with those). A quality alternator, like my mechman puts out IIRC 186 amps at 600rpms, and individually tested to put out 256 amps at IIRC 2200 rpms. Every alternator seller should be able to give you those two numbers, and even better a print out of the tested curve.

I think you do need a bigger alternator, (and if you haven't done it do the big 3), but I like overdoing it. This is still dependent on what kind of music you listen to, how loud you listen to it, what other electrical you have, whether or not that was peak numbers or RMS, (if those were peak numbers, then you shouldn't need a new alternator. You'd be using half those amps at normal volume). If those were RMS numbers, and you listen to it loudly, then you would want a larger alt. Then there's the gray area between.

If you do plan on getting a bigger alt, plan ahead, and think is there ANY CHANCE AT ALL, that you might want to do more eventually. Another or larger amp, lights, etc.... and if so, then plan ahead and buy the largest alternator you MIGHT need the first time. It will be a minimal difference to plan ahead and won't hurt anything to go bigger except for a few extra bucks.

 

Has anyone tried the 220 amp alt. from a 19 or 20 silverado? Looks like they have the same 2 pin connector. They are only $150 or so.

 

My guess is that won't work, but you should be able to search for that. Not only are they different designs, but In 2003, 2004, or 2005 they started using external voltage regulators, (the alt stopped just charging at full strength and dropping off the excess). The alts started being controlled by the ECU so they could charge less, to get better mpg. I would guess the newer generations would have different factors involved and better programming. Slowly its added up to doubling hwy mpg over the last 20 years.

 

You need a solid supply of current. An extra battery is a good place to start. A big current alternator isn't a bad idea, but that isn't going to solve all your problems like others have stated. Back in the day I thought a capacitor was the answer, but it will only do its job on the first bass hit. Then its recharging, then discharging while the system is starved of current. A mentor of mine suggested running an X-Static Bat Cap. Its like a battery, but can discharge faster. So its kinda like a battery and kinda like a capacitor. Bat Cap, not just a clever name.

The amps you've listed aren't crazy. Keep in mind the max power rating vs RMS power. You are likely never at max power because everything has clipped out at that point and sounds like crap. Build your setup for RMS power, usually half of the listed max. It is always recommended to have the largest gauge wire your amp can physically accept. If the supply wires are your bottle neck, they'll get hot in a hurry. Make sure you've already done the "big 3" wiring upgrade. If you're seeing your lights dim while running down the road, I'd seriously consider an additional battery or a bat cap.

 

So I found the big 3 upgrade (https://www.the12volt.com/installbay...id=73496&tpn=1)

Has anyone got a simplified parts list? Call me lazy, I'm ok wit that!

Chad

 

DC power is a good high amp at idle type alt. as well.

 

I had a Mechman 370A alternator for my setup in my 2015 Yukon XL (Wolfram W-4500 for subs, Rockford 600-4 for Highs over 5k RMS), along with three AGM Batteries. Yes they are externally regulated after 2004, but they still have a sensor to check charge state and current draw and then the PCM ramps it up if need be. These alternators produce more at idle than the stock ones do at 5000rpm, and they have a smaller pulley which requires an inch shorter belt. If you get one from a big name place, they make the power but you will pay (mine was $630).

The installation instructions stated that the case of the alternator had to be grounded back to the battery, but the case ground wire has to travel through the "hall sensor" so it would pick up the additional current draw. This sensor looks like a plastic loop and goes around your current ground in the vehicle (my 0 gauge fit through there).

Whenever my Yukon sensed a nice current draw, the voltage would increase accordingly, and remain stable.

Capacitors only give you a nice voltage display, unless you go with a super-capacitor which is way more than you need for your setup, and very expensive if you can get one.

With a bit over 1000 watts, I would use my current stock setup, and improve the "Big 3".

Now, dimming headlights will always happen with halogen headlights, as their brightness is dependent upon the voltage they receive (ie. brighter at 15V than they are at 12V...). The only way to combat this is with LED headlights or HID headlights which have a regulated power supply, and thus a continuous power demand.

 

ok so this is a easy one . All you need is a better battery and do a big 3 up grade . I ran a ds18 2k amp on all factory wiring.. the factory wiring is good up till 2000 watts after that you will start to see lights dimming under heavy bass..

you don’t need a bigger alt till ur in the 5k range and running more then one battery..
it would be better for you to run 1/0 wire to a distro block then run ur 4awg from there ..

 

GTFO here with that nonsense. You don't need a bigger alt until 5K watts? A 2013 runs at lower than 14 volts. I'll use 12 volts. 5,000 / 12 volts = 416 amps... So you think the stock 145 amp won't have any problem keeping up with an extra 400 amp draw? Even if I use 14.4 volts that's 347 amps EXTRA, beyond what the truck is using.

1/0 wire, why? Its an extra 1,000 watts for the amps, (i'll guess thats max. / 12), thats 83 amps. They've already gone up two sizes for what they would NEED. Unless thats RMS ratings, and they are running those wires all over the place and some how need 20+ feet, they are good.

OP, or any searcher, just in case: plan your wire for the entire length. Those amps are only 40 some amps, but calculate the load based on the length from the amps to the battery not the splitter.

 

dude don’t be a dick read what I said again.. if my 04 can run a 2k amp with no big 3 or anything just a 4awg amp kit with no dimming then his newer truck will have no issues with what I said since he is running less then 1000 watts.. what I said about 1/0 made sense as like my truck his stuff is under the hood so running a 1/0 ofc power to the back where his block will be is fine. It also gives him the ability to step up and not have to redo everything down the road if he wanted too.. he will however need a better battery . I can think of 3 batteries he can run right now that will charge off of 145 amps and be rated for 2-3500 watts which again is way more then he is even running..

so let’s use his 1000 watts at 12v that’s only 83.333 amps and knowing that most amps have rating for 12-14.4-16v he is fine with his stock alt and a bigger better battery ( a d4800 xs power is rated for 3000watts just a FYI).