Headlights dim when the music plays
How to give your car's electrical system a power-up
Your headlights dim when the stereo pulls too much power out of your car's electrical system. This usually happens only in large, multiple-kilowatt sound systems. But sometimes even modestly powered systems can stress your car's electronics, especially during a sub amp's burst of energy when it produces the sound of the beat. Every part of the electrical system suffers because of the amp's sudden demand on the limited supply of power, even the amplifier itself. Your eyes are just more sensitive to the change than your ears, and you notice your headlights dimming along with the beat.
There are a few actions you can take to solve this problem. There are also some strong and differing opinions about the order in which you should do them, or even their individual usefulness. The following is my contribution to the argument.
Sometimes all you need is a new battery terminal.
Check all power and ground connections, and the battery itself
The first thing you should do is make sure all the surfaces used in power and ground connections are scraped down to bare metal, clean, and all the connectors and the battery terminals fastened tightly together. If that doesn't do it, take your car and have its battery load-tested at an auto parts or battery store. They'll often do it for free and can recommend the proper replacement if they find your old battery has problems. Car batteries rarely live to be four years old, so don't think you're being cheated when they tell you your old battery isn't holding its charge. A weak battery can often have enough juice to start your car but not be able to handle the quick jolt of demand when your sub amp hits.
If you do decide you need to replace your battery, consider getting an XS Power battery from Crutchfield. XS Power batteries feature a sealed absorbed glass mat (AGM) design, instead of the standard liquid electrolyte design, so they actually store energy — meaning you don't have to add a capacitor to your system to get a quick burst when you need it. We carry a full assortment of the most popular sizes available. We even have models which fit many European applications such as VW/Audi, BMW, Mercedes, and Jaguar.
T-Spec 3.0-Farad capacitor
Capacitors
Adding a capacitor to your system does not increase your system's power capacity. But if your lights dim only occasionally, and only on the loud drum beats, then a capacitor may just be the cure. A capacitor smoothes out the power demands by providing a short burst of energy when needed. I recommend 2 farads of capacitor for every 1,000 watts RMS of total amplifier power. That's more than the usual recommended dose, but it should ensure a quicker recovery time for the cap to be ready for the next thump.
XS Power BIG3XS big 3 wiring upgrade kit
The Big Three wiring upgrade
A good, cost-effective improvement is to perform the "Big Three" electrical upgrade. This will vastly improve your vehicle's electrical system, allowing more current to flow easier to all components. This upgrade replaces or augments three key cables in the electrical system with 1/0 or 4 gauge wires: the battery ground to chassis wire, the chassis to engine block wire, and the alternator plus to battery plus wire. This increases your electrical system's current flow capability, ensuring a more consistent voltage under varying demand conditions.
An unfortunate possible side effect of doing the Big Three is that occasionally it only makes your lights dim even worse. This happens because the amplifier is now able to suck juice better from the system through the bigger straw (the new cables).
High output alternator
The alternator is the ultimate source for all of your vehicle's power when it's running. The battery starts the engine, but the alternator takes over when the motor starts to turn. If your sound system demands more power than your stock alternator can supply, then you will benefit by upgrading to a higher output alternator. Replacing your stock alternator with an "HO alt" may seem like an expensive solution, but if you've invested in a sound system that draws this much power, you shouldn't mind solving this problem of supply and demand by increasing the supply of power.
For example: producing a 1500 watt output requires about 217 amperes of current from your car's system. It's actually about a third of that for music, which doesn't put out full power all the time — but it's still a lot of current. Most stock alternators are in the 80-120 ampere range and can only supply about 40% to 50% of that for non-automotive uses like amplifiers.
A 250 or 300 ampere aftermarket high output alternator should provide enough power for all your car's systems and your high-powered stereo too. Keeping that in mind, calculating the required output size of a high output alternator is not easy and should only be done while consulting with the new alternator's vendor or installer.
XS Power car batteries
Adding a second battery
Another method is to add a second battery, often back near the amplifier. This, in effect, provides another source of power available to fill in the gaps when the system needs it. When the power is asked for, it comes from the batteries. Two batteries wired in parallel act like one battery with twice the capacity. Crutchfield carries secondary battery wiring kits that feature all the hardware necessary for adding a second battery to your system.
XS Power AK3500 secondary battery wiring kit
A second battery becomes almost necessary if you play your music a lot with the engine turned off. Some people use isolators between their batteries, so that the one used to start the car won't get drained by the amp's pull. And it's a good idea to only hook up two batteries of equal strength and age. The stress of two different strength batteries constantly cycling charge between themselves to equalize the voltage leads to a shortened life for both batteries.
Note: Working with a car's electrical system can be dangerous. Tools and jewelry can be welded by the inadvertent discharge of a battery or capacitor. Sparks could fly, igniting flammable gases. Batteries have been known to explode when overstressed. (I know it for a fact: I witnessed a friend's battery exploding and setting his Lincoln on fire.) If you're inexperienced or don't feel comfortable working with high-current devices, then hire a professional to do these upgrades and installations.
And please, don't let anyone talk you into doing any of these procedures unless you are experiencing bothersome headlight dimming.
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Donald Masci from Dallas GA
Posted on 2/27/2020What steps should I take if I have a 1996 Honda Passport, and I want to keep it stock audio-wise, but wish to add other electrical mods, such as a touchscreen windshield mirror and backup cameras? Would the drain be too high for an older vehicle, and where could I find beefier alternator and battery options for it?
Buck Pomerantz from Crutchfield on 2/27/2020Donald, Your mirror and backup camera will not draw nearly as much current as a typical subwoofer amplifier that would dim lights.Dino from City
Posted on 2/22/2020Hi i have 3000w rms amp if i get a 250 amp alternator can i run the stock 45amp battery or just one battery up front in my gen 8 civic. If so what amp battery?
James from Las Vegas
Posted on 2/5/2020Hey how r u i have been a fan of crutchfield sense it opened and i have two 500 watt rms Alpine going to two 2300 watt Type R duel 4 0hm subs wired to two ohm and i changed the wire and the Altanator to two gauge wire and 230 A Altanator and my Alt Gauge drops at idel to like 8-6 Amps and i have the 2 g coming straight from Alt to Batt and i have the Starter wired and two other wires all connected to pos in on Batt all wires but the wire for the amps are stock i think 1 of them are the alt gauge wire and it starts stays charged when i have it setting with alarm set for 3-4 days straight what do i need to do to stop and get an acerit charging reading thanks ahead of time
Gilbert rodegeb from San Francisco
Posted on 1/31/2020Hello I have a 2005 toyota camry Le I just got a new 100 amp alternator about 2 months ago, and a interstate battery in the front a while ago. I have a skar audio Zvx 15' wired 1ohm to a skar audio skv2 1500 amp and the headlights dim. Would a stronger battery (xs power, or stinger rated for the power) in the front fix the problem? I don't want to get a secondary battery.
Buck Pomerantz from Crutchfield on 1/31/2020Gilbert, I don't think a single battery upgrade will fix your issue. A new high-output alternator, about twice as powerful as the one you just got, might work better.Devin Ancrum from Newnan
Posted on 1/13/2020I have 2 8" IB kicker subs in my rear deck. 6x9 component set in the front , lc2i with a 2000 watt amp,this setup ran fine for 7 months when I had a 6.5 component set, now I swapped to 6x9 and I'm getting low voltage to my amp. I'm replacing my in-line fuse tomorrow , because I couldn't get an instant 13.5 volts on each side of the fuse. my electrical system ran this system fine yesterday no problem no dimming etc. If the fuse doesn't change anything do I really need to upgrade? because my amp won't ever turn on unless I jump the remote wire over.
Buck Pomerantz from Crutchfield on 1/14/2020Devon, It does sound like your fuse may have an intermittent break. If you bought your gear at Crutchfield, you could call Tech Support for free help troubleshooting your system. Their toll-free number is on your invoice. If you purchased your equipment elsewhere, you can still get expert Crutchfield Tech Support - 90 days-worth for only $30. Click on this link for details.Dustin Cousins from Toddville, Iowa
Posted on 12/21/2019Very informative article Mr. Buck Sir so first thank you for sharing. So I'm in a 2007 Toyota Yaris with stock 80amp alternator slamming 2 Kicker L7 Q series 15's in front of an Orion kx series 5000 watt rms amplifier. From the upgraded batteries terminals to the ground all connections are sound, the big 3 have been done, AGM battery installed, and stock alternator just replaced with a fresh OEM alternator yet I'm only able to experience about 25% of what this system can produce before it starves and turns off my head unit and nearly the entire vehicle. Dimming in the headlights is significant, extreme really. Do you think I should just jump and upgrade the alternator instead of wasting time with anything else? If so would you have any idea ballpark where a HO alternators output should be for my application? I'm in the rural Midwest and help does not exist near me on this topic so I am truly grateful for any advice you can offer.
Buck Pomerantz from Crutchfield on 12/23/2019Dustin, Rocking 5000 watts RMS puts this system into competition level, where two or three HO alternators are necessary as well as two or three batteries. Go to your favorite local auto repair shop and ask if they'll help you to order and install the extra electrical gear.Rigoberto
Posted on 12/21/2019So doing the big 3 wiring upgrade will occasionally make my headlight dimming worse ? That tradeoff is not worth it!
Santiago from Oklahoma
Posted on 12/20/2019I have 2014 GMC Sierra had aired and grab rca with input up output converter to get signal to amp it mmats 1000watts and 2 10 mmats they dim my lights and while driving they hit my stock stereo off and than turns back on is it pulling to much power and what can I do
Buck Pomerantz from Crutchfield on 12/20/2019Santiago, It sounds like the power and ground wiring may be loose Or, the amp is too powerful for the electrical system. If you bought your amp from Crutchfield, you could call Tech Support for free help troubleshooting your system. Their toll-free number is on your invoice. If you purchased your equipment elsewhere, you can still get expert Crutchfield Tech Support - 90 days-worth for only $30. Click on this link for details.Kevin McCubbi from Louisville
Posted on 12/12/2019Hey, I have a sa 12 v2 on 1000 Watts rms and a 1200 watt rms dc audio mono block amp. I haven't had the system installed yet because everything is stock as of right now, and the amp alt is 100 amps. What size amp alternator do I need to run this system efficiently?
Buck Pomerantz from Crutchfield on 12/13/2019Kevin, If your audio system overloads the vehicle's electrical system - lights dim when the bass hits - then getting a high-output (200A and higher) alternator may become necessary.Juan from Houston
Posted on 12/12/2019Hello my 2013 scion tc has a 100 amp alt and I have 2 Pioneer GM-D8604. 1 is running 100 watts x 4 @ 4 ohms and another running bridged 300 watts x 2 @ 4 ohms. My subs are running off the bridged amp. I run a pioneer deh-80prs usually around 37 to 42 on the volume. I wanted to know if it would be possible to upgrade the sub amp to something closer to 1500 watts @ either 2 ohm or at 1 ohm. I have no issues with light dimming at the moment. Can I possibly do this without a HO alternator?
Buck Pomerantz from Crutchfield on 12/13/2019Juan, Bumping your system's total output power from 700 to 1900 watts RMS may challenge your vehicle's electrical system, but the only way to find out if that's the case is to do it.-
Mario from San Antonio
Posted on 12/2/2019Buck, always interesting articles, I just bought a high output alternator (370 amp ) but I have had always connected the main battery to it, I have a secondary battery, that I have always used for my sound system, and also I have a battery isolator in the middle of both batteries, tell me if I can run another wire from the alternator to my secondary battery to have the same voltage (14.5 Volts) on both batteries and still have the isolator in between them? My two batteries are Kinetik 2400, but I bought the XS 3100 to replace my secondary battery. Thanks for your time and your opinion as well. Mario.
Buck Pomerantz from Crutchfield on 12/4/2019 Mario, If you run a wire from the secondary battery to the alternator, where the primary battery also connects, the two batteries won't be isolated anymore. Jeffrey from Charleroi
Posted on 11/25/2019Hello I have a 93 Geo Storm with a factory 75 amp alternater. I'm currently running a 600watt(max) system and the dome light dims slightly at Max volume when the bass kicks in. I'm about to move to a 3100watt(max) system as far as amplifier but it's only 1650watt(max) as far as speakers. I already made sure that it will all work together,but I know I'm gonna need more power than I currently have. So I'm wondering what size alternator I would need/if I need dual alternators I'm also not completely sure of what grade wiring I would need for it all
Buck Pomerantz from Crutchfield on 11/25/2019 Jeffrey, Never use max ratings, when planning a system, always use RMS ratings. If your lights dim a little now, they'll do it a lot after the upgrade. If you're really going to increase your amplifier power by five or six times, you'll need to get the largest HO alternator your car can support. Geoffrey Koelzer from Sunnyvale,ca
Posted on 11/23/2019Hi there everyone! I am a huge Crutchfield fan, anywho: I have a high output alternator I am installing it with the big three on a difficult Ford Escape. My initial impression was to fuse the positive wire leading to the battery with the alt with the same size fuse(300ampsANL). Does this work or should I have the next highest recommendation fuse at 325 amp to protect alt from battery?
Buck Pomerantz from Crutchfield on 11/25/2019 Geoffrey, The fuse size depends on what size wire you're using. If 4-gauge, then I'd recommend an 85-100A fuse. If 1/0-gauge wire, use a 200-250A fuse. Matthew from NORWALK
Posted on 10/28/2019Hello, I have a 2013 Subaru Legacy with a stock alternator which is 110amps (I think , cant find much on internet) I have an Alpine MRV-500 pushing a 450w rms Hifonics sub and want to put in a 600X4w amp for my front components drawing 75per channel at 4ohms. I am doing the big 3 now but wanted to know if i will need batteries or a bigger alternator. Thanks
Buck Pomerantz from Crutchfield
on 10/29/2019 Matthew, The only way to find out if you'll need upgrades is to go ahead and install the system and see if your lights dim on big bass hits. Tony from Hoffman estates
Posted on 10/17/2019Hi i have a 2003 cadillac deville i want to put in 2 1200 watt subwoofers. What size amp should i install. Also would a 300 amp alternator work with this set up?
Buck Pomerantz from Crutchfield on 10/18/2019 Tony, Without knowing precisely what sub you're referring to, we can't help you with advice. If you want a question answered about a system, you must identify the gear by brand names and model numbers so we can get the right information to you. omar barron from fort worth
Posted on 10/13/2019hello good sir.. i have a 15 f150 has a 200 amp stock alternator and factory battery im looking to add 1 12 sub and a 1500 amp wired at 1 ohm 900 rms total will i be safe without having to do any other upgrades to the stock eletrical system ? thanks in advance
Buck Pomerantz from Crutchfield on 10/15/2019 Omar, Your vehicle's electrical system will most likely handle that amp safely. Dan from San Diego
Posted on 10/9/2019Hi Buck, I am a long time reader of yours and appreciate the advice. I have a build I am starting on my 2017 mustang; the main parts will be two AudioControl ACM - 4.300 amps to power the Focal components and Focal 2 ways in the back. The Focal sub will be powered by one AudioControl ACM - 2.300 with a 4 ohm bridge for 300 watts. All 8 channels and the sub will be 700 RMS total. I will control everything with a AudioControl DM-810. As for wiring, I am running 1/0 gauge OFC that splits to 4 gauge to feed the amps in the trunk. I planned on doing the big 3 upgrade with 0 gauge prior to the install but after reading your advice I have questions if it will really be necessary. I have 4 questions I would like to ask. 1: As stated, I will be running 3 AudioControl amps (class D) for a total of 700 watts RMS. The car has a stock 175 amp alternator and I am going for sound quality and not thumping volume (I am in my 50's). Do you think the Big 3 is necessary? 2: If I do the Big 3, I want to fuse it; should I fuse close to the battery or the alternator? The alternator is on the opposite side of the engine from the battery so I would have to run about 8 feet of cable. 3: The 0 gauge I bought is rated up to 300 amps and I purchased a 250 amp JL Audio ANL fuse; would this be sufficient for the big 3? 4: I also plan to fuse the 0 gauge amp feed to the trunk at 150 amps at the battery (the 3 AudioControl amps have built in 30 amp fuses). Would this be OK? Thanks Buc
Buck Pomerantz from Crutchfield on 10/10/2019 Dan, I assume you plan to bridge those amps, right? Bridge one 4-channel amp to drive two sets of front components (150 watts RMS each, 300 together); bridge another one for the two rear speakers (150 watts RMS each, 300 together); and bridge the 2-channel amp for the sub (300 watts RMS) and the grand total will be 900 watts RMS. Using 75% as the amps' efficiency and 13.8 volts as the running voltage, they will draw 86A when they're all going full blast at the same time. That doesn't happen with music. 4-gauge power wiring with a 100-amp fuse will be more than adequate for your setup. But using 1/0-gauge won't hurt. I doubt a Big Three update will be of any benefit to a system this size, but probably wouldn't hurt it either. JL Audio recommends mounting the fuse near the alternator, but I'm not sure I agree. The fuse sizes you mention are reasonable. Brad from Warsaw, IN
Posted on 9/26/2019Hi Buck, love your advice and have been getting a good laugh reading your Q&A! Do you have any coal fired power plants that will fit in the trunk of a car to power some of these systems people are trying to run? ??
Franz J. from Springfield, MO
Posted on 9/13/2019Hi Buck, I really appreciate how helpful you are about answering questions for Crutchfield... I will try to keep this simple... I have a 3000 watt amp powering 2x 15" 1500 watt subs set at a 2ohm load... I'm concerned about protecting my electrical system... I have a Chevy Avalanche with a 145 amp alternator... what enhancements would you recommend to keep everything running smooth..?
Buck Pomerantz from Crutchfield on 9/16/2019 Franz, If your vehicle's lights dim when the bass hits, you could do like the article suggests and put in a second battery or high-output alternator. Kenny from Phoenix
Posted on 8/26/2019Hello I have a 2015 Malibu and I was wondering if it would be ok to run a single Kicker L7 12" with a Kicker KXA800.1 amp? will this draw too much power from my car?
Buck Pomerantz from Crutchfield on 8/27/2019 Kenny, Most vehicle electrical systems can handle an amp that large. Gerald Hunter from Jacksonville
Posted on 8/12/2019I have a 2018 impala LT 150amp alternator currently all big 3 are 4AWG. I'm running JL audio c2650 ,c2650x , 12W3v3 and HD900/5 with 4AWG jl premium kit. I'm wondering ahould I have any issues? At the moment I get dimming lights at higher volume for the sub and the light on the HD900/5 goes red after being played on high volumes for a while.
Buck Pomerantz from Crutchfield on 8/12/2019 Gerald, Your issue may be loose power and/or ground wiring, a weak battery, or the sub channel's gain is set too high. Chris from Houston
Posted on 7/18/2019Hey! Chris wtih a 06 navigator. I have 2 nsv4 wired at half a ohm and a 4500.1 (4500 watts rms) wolfram amp pushing it. i have a stock alternator, big 3 upgrade with 2/0 gauge ofc wielding wires, 300 a fuse, and i use the 2/0 wleding wires for my whole set up along with 8 gauge speaker wires for the subs. i have a yellow top up front and a limitless lithuim battery thats 25AH 4500w at 12v with 150a of available charging. Is this a good set up? or am i killing my alternator? Also i recently added a 4 channel kappa amp thats 1200 watts .
Buck Pomerantz from Crutchfield on 7/22/2019 Chris, That amplifier is not stable pushing a one-half ohm load, and can draw as much as 450A from your electrical system. I think you'll need more than just a second battery to use this amplifier in your vehicle. Mikhail Jackson from Cincinnati
Posted on 7/16/2019I have a 2018 Hyundai Elantra SEL with a stock 150A Alternator and an OEM 60A battery. Will a Infinity K4 (x100RMS 4-Channel at 4-Ohm amp) and an infinity K600 (x600RMS at 2-Ohm amp(I plan on using a 4-Ohm sub that's rated at 300 watts RMS)) work perfectly without any issues in my car?
Buck Pomerantz from Crutchfield on 7/16/2019 Mikhail, If those two amplifier were both playing at their loudest, most powerful output, they'd be drawing about 68 amperes. An alternator usually has one-half of its total output available for aftermarket gear. So, in your case, one-half of 150 is 75, which is more than the 68-ampere demand. You'll be okay with the gear you have. Daniel from Beaver Dam
Posted on 7/14/2019Hi there I have 2 15 suds both wired parallel to like 1 ohm I think they're only getting to home I have a 4000 watt RMS amp and I'm going to add one or two more amps I'm adding one for sure it'll be less amps for the door speaker if you like a four channel thousand wok I have one more 4000 w RMS that I'm going to bridge eventually and im doing the big 3 upgrade either 1/0 awg or 2 awg but I'm still using my stock alternator I was going to get a 250 amp alternator would that be enough I also have a power cap with 50 farad that I'm installing but would 250 alternator be good enough or can I go smaller?
Buck Pomerantz from Crutchfield on 7/16/2019 Daniel, One 4000 watts RMS Class D amplifier will have a top electrical draw of about 386 amperes, and would probably overwhelm the kinds of electrical systems you're talking about. William from Los Angeles
Posted on 6/9/2019I have a stock Honda 2014 CRV, I am running a Alpine iLX W650 and bought a Alpine PWE-S8 powered sub. Can I use the existing power line from the stock radio harness to power the sub also?
Buck Pomerantz from Crutchfield on 6/10/2019 William, That powered sub needs its power lead connected directly to the battery. We recommend using 10-gauge power and ground wires. BAYANI CRUZ from Manila Philipphines
Posted on 5/10/2019Gud day sir..i'm here in the manila phil..i would like to ask ..f i can install big 3 update in my toyota vios 2011 even though i would not install high cap audio set ?ty and more power
Buck Pomerantz from Crutchfield on 5/13/2019 Bayani, Installing a Big Three upgrade on your vehicle won't hurt anything, will improve current flow, but won't actually add any power to the electrical system. Ken from St Clair Shores
Posted on 5/9/2019I have a 2008 Dodge Ram 1500 Big Horn. It has a 160 Amp alternator. My battery is a Bosch 65-850B, 1000 CA's. 850CCA's. I have done the "big 3 upgrade". I have a JBL GTO-751EZ set to 800 watts RMS (it actually puts out much more before clipping) powering two 10" Kicker CompVT's at 2 ohms, an NVX Jad800.4 powering just my front SPR-69's and SPR-10tw's (100W RMS x2, just the front two channels for now). I'm getting headlight dimming at higher volume, and occasionally the GTO-751EZ will turn off/go into protect. I have 0 gauge wire coming from the battery to a splitter under my rear seat where 4 gauge goes to the sub amp, and 4 gauge also goes to the 4 channel amp. At times when the bass notes hit, I can see the voltage drop from 14.4V down to 12.5V. I suspect my alternator can't keep up with the demands, but the battery is 4 years old. I'm debating on replacing either the alternator or the battery, and I would love to hear your opinion.
Buck Pomerantz from Crutchfield on 5/10/2019 Ken, It sounds like your subwoofers are wired together such that the amp is seeing a 1-ohm load, and it doesn't like that and goes to protection. It also sounds like a power or ground connection is loose. Check the wiring and then the battery. That strong alternator should have no problem powering your amplifiers. Dominic from Norfolk, UK
Posted on 4/23/2019Hi Buck, I'm upgrading from my existing system (Head unit running 4 door speakers and a 150w RMS powered subwoofer) and I'll like some amplifer advice. I've ordered the Pioneer GM-D1004 (4x45w RMS for the 4 door speakers HPF at 80hz) and I don't know whether to get a 300w RMS or 500w RMS at 4ohm amplifier for my new 12" JBL GT5-12 subwoofer. I'm deciding between the GM-D8701 and the GM-D9701 monoblocks both Class-D. My car is a 2003 Ford Focus and it has an 80A alternator. Will I be straining the alternator with the 500w amp? Or would 300w be enough to provide a heavy low end against the 4 speaker setup I mentioned? Thanks
Buck Pomerantz from Crutchfield on 4/25/2019 Dominic, The 500 watt amp will provide a better level of bass to match the power of the other amp. Your vehicle's electrical system should handle all of this setup okay. Paul hendrickson from Forney
Posted on 3/30/2019I have a 2016 jeep patriot with 2 scar audio 2k amps, 2 sundown x10 rev1 subs, 270amp mechman alternator, 2 optima red caps in the rear and one under the hood. I just upgraded my whole wiring setup from a single run of 1/0 to a double run of 2/0 (meaning double run from alt to batt, batt to two 300amp fuses, fuses to another set of 300amp fuses, fuses to batteries in the rear, and a double run of 1/0 connecting the rear batts in parallel, and a single run of 1/0 from the batteries to the amps.) Originally with the single run of 1/0, i have a solid 14.2v at the front batt, but it dropped to 13.2 in the rear, so i upgraded all of the wiring to dual 2/0, now i have 12.6v in the rear. And im not sure why i lost so much power flow to the rear, any thoughts??
Paul Moore from San Antonio
Posted on 3/12/2019Hi Buck I have a 2008 Chevy Tahoe I am looking for the best option for my setup I have been through three alternators in the last two weeks since system was put in running a 1,000 watts rms on a 160amp alternator and the alternator keeps going out what can I do to avoid this one from going out? No headlight diming when bumping no issues I see but just goes out
Buck Pomerantz from Crutchfield on 3/13/2019 Paul, A 1000-watt amplifier shouldn't take down a 160-amp alternator unless there were some other wiring issues like loose connectors. But if everything's right about the wiring, you may need to go to your local car shop and have them install a high-output alternator to run your vehicle and sound system. Matthew from Phoeinx
Posted on 1/18/2019Hello! I am going to be installing 2 MTX 5500 12's, an MTX XThunder 1200W mono for them, a 500w 4-chan MTX for the high end. So, we are looking at 1500-1800w. This is in my tacoma 2001 3.6L. I WILL upgrade the alternator to a high output 190amp alternator. I am also going to get a good battery (maybe one of Crutchfield's) and a solid 4farad cap. I do NOT want any dimming of lights. I usually don't crank it up, but when i want to blast it, i want a solid bank of constant electricity. Is this good???
Buck Pomerantz from Crutchfield on 1/21/2019 Matthew, That sounds like a good plan, to me. C from Philly
Posted on 1/1/2019Always use biggest wire possible. Dont use 8 gauge w a 1500 watt amp dont run threw door jambs dont be that guy!!
Shane Fine from Charleroi
Posted on 12/6/2018My 2014 volkswagen jetta with fender system has a 140 amp alternator. Will that be able to run a 2 ohms 500W x 1 amp and a 4 ohms 125w x 4 channel amp.
Buck Pomerantz from Crutchfield on 12/6/2018 Shane, That amount of power is just on the good side of the cusp of needing some electrical updating in order for the system to work properly. The figuring goes: you want 1000 watts RMS total, so 80% efficient Class D amps will try to pull 1250 watts RMS from the electrical system. At 14 volts, the draw is 89 amperes. But full-range loud rock music has a duty cycle of 30%, which means the continuous current demand will be more like 27 amperes. The rule of thumb for alternators is that one-half of their current capacity is available for aftermarket goodies like amps - 70 amperes in your case. You should be fine playing that system in your car. Tim from Belleville
Posted on 11/29/2018Hi I have a 2012 impala ltz and 2 12 inch rockford to punches 1400 rms a piece running off of the 1200.1 prime amp turned almost all the way down it dims every light in my car besides the headlights because they're after market leds but it pulls so much power it'll lose power and my car will say service stabilatrak and it'll briefly shut my car off while I'm driving in trying to see what kind of ho alt I should go with
Charvis from Gordon ga,
Posted on 10/20/2018Hey how you doing my name charvis & im sort of in a pickle like I have 2 12 bd3 Audiopipes 1800 watts each rms 900 each running off a alpine 1200 watts competition amplifier & my lights do dim I have my system in a 91 Chevy caprice classic v8 305 5.0 I still have my stock alternator I was wondering if I could somehow move the 120 amps alternator up to 220 amp would i still need a second battery or the big 3 or would cause damage to just get the alternator boost to 220 amps
Buck Pomerantz from Crutchfield on 10/23/2018 Charvis, An upgraded alternator shouldn't put any extra stress on your vehicle's system, but should provide a larger capacity for current to flow. You should try one electrical upgrade, before thinking about doing two or three. Nathan Sumner from Asheville, NC
Posted on 9/12/2018Buck, I have a 2007 Tahoe with a stock 160 AMP alternator, and brand new battery. I have bought the (2) Kicker L7S at 750 Watts each. I haven't bought a amp yet and want to know if I went with the Kicker CXA1200.1 would I need to upgrade any electronics. I want the Kicker CXA1800.1 but I am afraid I will have to put a ton of money in electrical upgrades. Side note: I'm not looking to blow my doors off so I am ok with the 1200 Watt amp
Buck Pomerantz from Crutchfield on 9/14/2018 Nathan, That amp trying to put out 1200 watts RMS, or 85.7A, may very well tax your vehicle's electrical system. If so, you may need to put in a second battery or a high-output alternator to combat light-dimming. Harry from Florida
Posted on 9/6/2018Hi buck. I am a complete newbie when it comes to audio upgrades. I'm trying to make a simple audio upgrade and would love your thoughts on this. I have a 2004 Jeep grand Cherokee limited 4.7 litre V8. I am planning on upgrading the four door speakers (2 front, 2 rear) to speakers that have power output of 100rms and 4 ohm of impedance each. I thought of adding a four channel 800 watt A/B class amplifier that has a RMS of 100 watt per channel at 4 ohms. I have a 130 amp alternator, would I have to get a ho alternator or a second battery? And would you recommend anything to be done differently. Thanks :)
Buck Pomerantz from Crutchfield on 9/8/2018 Harry, That gear should work fine in your vehicle with no need for a high-output alternator or a second battery. Jesse from Morgantown
Posted on 8/5/2018Hello, i have a 2018 Jeep Wrangler JL with a 240 amp alternator and a 700 amp battery. Is there any idea on how much wattage I could run without facing any issues?
Buck Pomerantz from Crutchfield on 8/6/2018 Jesse, In general, one-half of an alternator's output is available for your aftermarket equipment. A 240-Amp alternator can support amplifiers that can draw a total of up to 120 Amps. This translates to about 1344 watts RMS for Class D amplifiers, and 840 watts RMS for AB amplifiers. Brandon from Beaufort
Posted on 7/21/2018So I'm running 3k total doing the big 3 with 250 hours alt and extra battery. Is this to much? Just unloaded for a nice setup not trying to skimp out now want the best I can get out of the system
Jason from Mckinleyville
Posted on 7/19/2018One more question about my civic with 1500 watt system. Would you suggest a second battery like the xp 750 or 950, or a deep cell starter battery like the D5100r, again this to fix headlight dimming and allow for longer play when car is not running. Thanks.
Jason from Mckinleyville
Posted on 7/14/2018I'm running 1500w on a stock alternator in my 95 civic. I'm experiencing headlight dimming, and would also like to be able to play music longer when car is not running. I'm considering adding an xs750, or xs950 supplemental battery with an isolator. I've read that the extra battery will do nothing to help the headlight dimming while the car is running, what are your thoughts on my battery choice and the matter of dimming. Thanks.
Buck Pomerantz from Crutchfield on 7/16/2018 Jason, In spite of what you've read elsewhere, adding a second battery will help overcome light-dimming. It may not entirely solve the issue, but it won't hurt either. Brett from oceanside
Posted on 6/19/2018currently have 2 12" audiopipe subwoofers wired to a CT Sounds 1500 watt amp in my '07 Avalanche. Still running a stock battery and alternator but I just did the big 3 upgrade and my lights still dim. I'm not sure what model my Subwoofers are or the ohms because I had very little knowledge on stereo systems when they were installed. but I'm looking to go to an HO alternator, is this the right move?
Buck Pomerantz from Crutchfield on 6/20/2018 Brett, Upgrading your alternator will definitely help the electrical system, especially while driving. Another strategy you might employ to prevent light-dimming is to add a second battery to the system. Chance from Tampa, FL. (Seffner)
Posted on 6/12/2018I have a 2007 Nissan Altima 3.5L V6 and I'm having a sound system installed. (JL Audio 12W7AE-3 12" 3-Ohm Sub w/ JLAudio JX1000/1D 1000 watt RMS Amp) I am considering an alternator upgrade but I don't know if its needed or even what I have as factory OEM on my Altima to begin with. I welcome your feedback. Thank You.
Buck Pomerantz from Crutchfield on 6/13/2018 Chance, Don't try and solve a problem you don't have. You shouldn't even consider an electrical upgrade until after your amp installation, and your vehicle's lights dim on bass beats. Mike Bennett from Grayslake
Posted on 6/3/2018My headlights dim bad. I have a 2013 Honda Civic LX, and I am running a kicker cxa 1200 and an audiopipe Q-15, both rated at 1200 rms. Is this too much? I have been told this is too much and should consider getting different, less powerful gear. But before I do that I'd like to know if that's true and get a second opinion, or if adding an alternator will solve this problem. I was also told that could cause my electrical system to fail (not the alt, but the setup being too powerful) and would also like to know if this is true and am I putting my car in danger by running sucha powerful set up on a stock electrical system? Help would be appreciated!
Buck Pomerantz from Crutchfield
Posted on 5/8/2018Gregory, I think a second battery should be connected in parallel to the primary battery, not directly to the alternator. The Big Three is an independent upgrade that isn't required, but probably wouldn't hurt.
Gregory Horton from Eutaw
Posted on 5/7/2018Can i run my rear battery bank straight off my alternator.. if i do will i still need the big 3..
Buck Pomerantz from Crutchfield
Posted on 5/4/2018Matt, A system that massive will need more than what you propose - its peak demand will be in the 335- to 536-A range.
Matt from Gilbert
Posted on 5/2/2018Planning on buying 2 subs that pull 1500rms each, so a total of 3000. Plus 4 door speakers with 100rms each = 400rms. The amplifiers im looking at are rated 500rms (for the 4 doors) and 3300rms ( for the subs). So I have a total of 3700rms drawing from my 2015 nissan versa alternator providing 110amps. Obviously need a new alternator. Would a 270amp alternator suffice? Or would it be best to buy both a 270amp alt and a 2nd battery?
Buck Pomerantz from Crutchfield
Posted on 3/26/2018Robert, Sundown SA-12 subs come in DVC 2-ohm and DVC 4-ohm models. If yours is the DVC 2-ohm model, the only safe way to wire it to that amp is like this diagram, getting 400 watts RMS to the 750 watts RMS rated sub. If your sub is the DVC 4-ohm model, the best way to wire it would be like this, getting the 750-watt sub 750 watts. Neither setup should tax your vehicle's electrical system.
Robert from Ontario
Posted on 3/23/2018Hi Buck, Thanks for all your advice and articles on sound systems. I have a question. I have a 2016 Dodge Charger with a stock 180 amp alternator. I'm going to use an audiocontrol 1200 amp. I'm trying to decide if I should power it at 750 watts rms at 2 ohms or at 1200 watts rms at 1 ohm for one Sundown SA-12 sub. Will either of the two choices tax the electrical or am I in a "safe zone" with one or both wattages?
Buck Pomerantz from Crutchfield
Posted on 3/22/2018Jesus, That should do it and then some.
Jesus zuniga from Denver
Posted on 3/21/2018So a 250 amp alternator be enough for my sound system
Buck Pomerantz from Crutchfield
Posted on 3/21/2018Dale, There's no way to know if you need an electrical upgrade or not until after it's all connected and you experience light-dimming.
Buck Pomerantz from Crutchfield
Posted on 3/21/2018Jesus, At full blast, that amp will try to pull as much as 109A from the electrical system. Beefing up your system to 120A probably won't do much good. A 200A probably would.
Buck Pomerantz from Crutchfield
Posted on 3/21/2018Cletus, You can have an auto parts store check your alternator's voltage regulator for malfunction, but please do not bypass any factory harness of your vehicle's electrical system. That would be dangerous. The fact that your amplifiers will try to draw as much as 235A from a 160A system tells me you probably need a larger or a second alternator.
Dale from Cincinnati
Posted on 3/18/2018I just got 200 high output police alternator for grand marquis with 3000 watt taramp can I run it I have good battery to I got it tested pushing 12.9 volts with 0 gauge but not big 3 would I need extra battery or it should be fine with proper gain I haven't hook up yet
Jesus zuniga from Denver
Posted on 3/18/2018Hi I have 2 sundown sa-10 Rev 3 RMS 750 Dual 4 ohm with a class d amp hifonics Brutus 1200.1D wired to 1 ohm. My issue is I can't find a ho alternator for my 2012 civic LX sedan. My question is will rewinding my 90amp alternator to 120 amp help my electrical system or do I just to the big 3 with upgrading my ground cable too. Im just trying to get rid of the light diming of my headlights
Cletus Bosephus Rodriguez from HomeoftheRazorbacks
Posted on 3/17/2018Hello Buck, I would like to get your opinion on a headlight flickering problem. I have a 2002 Honda Civic. The stereo I'm running is: 1 - 12" L7 solo baric powered by an Orion XTR1500 2 - MB quart 6.5s, 2 - MB quart 6x9s, powered by an MB quart 4x120 amp. I put an ultima yellow top battery, Rockville RXC50D 50 Farad cap, and a 160 Amp Alternator. I have also replaced the big three wires with 1/0 5250 strand wire. I'm getting dimming on my headlights and interior lights when the bass hits. It's not extreme, but it's noticeable. I'm suspecting the voltage regulator on the alternator because it's wiring runs through the car's wiring harness. Is there a safe way to test this theory and bypass either the car's wiring harness or the voltage regulator without overcharging the battery? Do you have any other ideas on how I can eliminate the dimming?
Buck Pomerantz from Crutchfield
Posted on 3/9/2018William, Performing the Big Three upgrade is never a requirement when beefing up an electrical system, but it probably won't hurt either.
William Hall from Canton
Posted on 3/9/2018No matter what I'm adding a extra battery but should I also do the big 3 upgrade when sitting and not moving with the subs on I watch my voltage meter jump and bounce I have a good battery in it
Buck Pomerantz from Crutchfield
Posted on 3/6/2018Lance, It won't hurt anything to get a high-output alternator in order to support such a large amp, and may be just what you need.
Lance Nicholas Welch from INDIANAPOLIS
Posted on 3/2/2018I have a 4.2 trsilblazer. I am adding a sundown X 12v.1 and the amp will be a HIFI BRZ 2400 1.d. all off my buddies are in competition and are telling me i need to get a 270 alt and a solid battery. Can i get away with the big 3 (OFC) of course and a decent set of matching agm battiries? I just downgraded due to soace. I had a toyota 4 runner with a maxive box tuned to 31. So i am sure i will not have quite the sane output. But power wise would it be wise to get the 270 alt??
Buck Pomerantz from Crutchfield
Posted on 1/29/2018Adam, An amplifier's gain control is there to match the amp's input sensitivity to your receiver's output strength. Wanting that control set at any number is not the way to properly set it. You turn it up until you hear distortion, then turn it down until the distortion goes away. Your amp's wiring setup is straining your car's charging system. First, check the battery and wiring. If they're okay you can then replace your power wire with the correct 4-gauge wiring. And then apply more of the suggestions spelled out in the article.
Adam Malik from newnan
Posted on 1/29/2018Hi, i currently have a Rockford fosgate 12 inch enclosure with a 600 watt rms and 1200 watt max rating with a Rockford fosgate mono amplifier with a 750 watt rms installed. I want to be able to fully listen to the sub without causing any damage to my car. When the volume is turned to about less than halfway and a loud bass note hits, all my lights will flicker, interior and exterior. And I only have the gain set to about 4 but it goes up to 11. I want to be able to have it set around 7-8 without my lights flickering. But I installed this with 8 gauge power and ground wire so is this why my lights are flickering? if i were to change the wires to 4 gauge, would this solve my problem? I've done some research and found that 8 gauge only has a max of 600 watts so I'm not sure if i used the wrong wires and if i should swap for the 4 gauge instead.
Buck Pomerantz from Crutchfield
Posted on 1/15/2018Westley, The information I see about that mono amplifier is that it can put out up to 6,500 watts RMS at 1 ohm. Adding a 125 watts RMS per channel 4-channel amp brings the total wattage to 7,000 watts RMS. To produce this massive amount of output "all day" out of, let's say, 80% efficient Class D amplifiers with a 13.8 volt supply will require 634 amperes. Even if you're starting with a 130A factory alternator, adding a 370A might not support the full output you're looking for. You might be able to play loud music with no light-dimming with your planned upgrade - the 1/3 duty-cycle of music means the amp is only asked to produce top wattage 33% of the time - but "demoing all day," probably not without more upgrading.
Westley Gaskins from moncks corner
Posted on 1/15/2018I like this thread. None of this is installed yet, but I have a mechman 370 amp hi output alt on a bracket separate from stock alt, 2 xs 7500d batts ran in parallel, 1 ns-1 sundown amp (10,000 watt ems) powering 2 sundown nightshade v4's 3000 watt rms 15 inch subs, a sundown 125x4 v.2 on 4 jl audio 3 component 6x9s and 2 skar audio super tweeters with inline bass blockers. All with ofc certified basshead 1/0 power and ground, ofc 8 gauge ran for subs. The question is am I done buying parts? With all this power can I demo all day? Will this power supply work or do I need more?
Buck Pomerantz from Crutchfield
Posted on 12/6/2017Anthony, We don't sell alternators nor make specific recommendations about them. I'm not familiar with what's available in your country, but if you're really putting in an amp that size, you'll probably need a high-output alternator that can supply about 75 to 100 amperes beyond the electrical needs of the vehicle, plus a second battery.
Anthony from Durban
Posted on 12/5/2017Hi. I currently have a 2017 Hyundai i20 1.2 Motion and I want to add a 2500w rms sub with a 2500w 2ohm rms amp. What alternator would I need to run this system smoothly and would the stock battery work? Thanks
Justus from Geronimo
Posted on 12/3/2017Sooooo, when are you guys getting into the HO Alternator game? I can buy just about every other part of an audio system but that.
Buck Pomerantz from Crutchfield
Posted on 11/30/2017Jordan, It could be that your amp's gain is set incorrectly and it goes into protection mode due to being overdriven. I doubt your vehicle's alternator has anything to do with the issue. If you bought your gear from Crutchfield, you could call Tech Support for free help troubleshooting your system. Their toll-free number is on your invoice. If you purchased your equipment elsewhere, you can still get expert Crutchfield Tech Support - 90 days-worth for only $30. Click on this link for details.
Jordan from Ephrata
Posted on 11/30/2017Hi I recently started having an issue where my subwoofer shuts off/loses power when I turn my volume to about 70% max. I think it's my alternator but could it be my amp? I have a 5 channel for my speakers and another amp just for the sub.
Buck Pomerantz from Crutchfield
Posted on 11/15/2017Mark, You don't have to worry about anything. If, after installing and setting up your system, you experience light-dimming when the bass hits, then you can revisit this article for possible solutions. You shouldn't have to solve a problem until it actually exists.
Mark from Norwich
Posted on 11/13/2017Hi Buck. I'm planning some upgrades and was lead here by a friend after he mentioned the big 3. My total RMS will only be 700w RMS, do I need to worry about this? I checked my alternator and it's rated at 90a.
Buck Pomerantz from Crutchfield
Posted on 8/14/2017James, I assume you're referring to Kicker's CXA1800.1 amplifier, which can put out up to 1800 watts RMS through a 2-ohm load. It should have 1/0-gauge power and ground wiring, in order to produce its rated power. Perhaps it goes into protection mode due to it being stressed with an inadequate power supply. If your lights dim on loud musical beats, then upgrading the alternator will probably help.
James from canton
Posted on 8/11/2017I have an 03 malibu with 2 15in kicker L7s 4ohm wired to a 3600 watt kicker amp. It is not hitting to its full potential i know bc i had 2 12in kicker L7s. I have to upgrade from 4 gauge wiring to 1/0 but is that the only thing throwing my amp into protective mode? wasn't sure if i need to upgrade my alternator or not?
Buck Pomerantz from Crutchfield
Posted on 7/29/2017Ian, If your amplifier stays on after the stereo is turned off, its remote turn-on lead is not wired properly - the amp should turn off when the stereo does. Otherwise what you describe sounds like a loose ground or power wire, not an alternator issue.
Ian Wallis from Sydney
Posted on 7/29/2017Hi Buck, Some great information here. I have a Kenwood KAC-PS527 2 Channel Car Amplifier powering 2 x Pioneer TS-A6975S speakers in a 1973 HQ Holden. I get crackling and a popping speaker sound when the car is running with stereo turned off. I think it may be the alternator (Ingram - possibly a 55Amp). What would be the recommended sized alternator if this is the issue? There is some pretty serious gauge power and ground cables going to the AMP. Thanks in advance.
Buck Pomerantz from Crutchfield
Posted on 7/15/2017Brandon, Let me start with that first calculation. For car audio power supply planning, we assume a 50% efficient Class A/B amplifier is being used. To produce a 1500 watts RMS output will require 3000 watts RMS power from the vehicle's power supply. Using 13.8 volts gives us 217.39 amperes of current draw. See our Wire Gauge Chart for more information. Your second question is the million-dollar question of the decade: Does a capacitor do any good in a car audio power supply circuit? A capacitor is used for two things in car audio: filtering out any AC in the 12-volt DC signal, and to "stiffen" the system voltage to prevent lights from dimming when loud bass notes play. They accomplish this by supplying the amplifier with a quick jolt of power. Here's an article that may shed some light on that subject: Capacitor FAQ.
Brandon Briggs from Muskegon
Posted on 7/14/2017Hello, I'm just curious if normal rules of electricity apply to sound system power. I'm an electrician and know ohms law and power calculations. How does 1500 watt draw equate to 247 amps. P= I×E Power =watts I= current or Amps and E= voltage. 1500 watts divided by 12 volts equals 125 amps. My car runs around 13.7 volts when running which would equate to even less current (110 amps) I read a bunch of stuff not only here but other places with knowledgeable people such as yourself where their calculations doesn't add up to what I was taught in my IBEW apprenticeship program. I understand that none of these devices are 100% efficient but even to get over 100 amps of lost power due to resistance, making heat or electromagnetic effects doesn't make sense. My other question is how does a capacitor work in a DC system. Capacitance along with induction only exist in an AC circuit. All of the capacitor I've seen are supposed to be installed before the amp which is DC. Capacitive Reactance formula is Xc = 1/(2×p×frequency× capacitor value). But because DC has no frequency that value would be 0 which messes up the whole equation. I could somewhat see a capacitor working after the amp which is an AC circuit but the frequency value is constantly changing. Is there special rules that apply to sound systems or electronics? If so could you point me in the right direction to learn more about this.
Buck Pomerantz from Crutchfield
Posted on 6/27/2017Razaad, Not knowing exactly what amplifier you have (brand name and model number) makes it difficult to determine whether your capacitor is appropriate or not. The fact that your power wire fuse blows tells me that something's wrong. The power cable should be the same size wire from battery to amp, and the ground wire should be the same size as that. So should any wires connecting a capacitor.
Razaad Ahmad from Bethlehem.
Posted on 6/27/2017Hey there. I have 2 Skar VVXv3 12" subwoofers running in my Nissan Altima 2005. I have the 1500rms amp running those two subs. My question is should I include a smaller cap? I have an 8fraud cap. Also I've noticed the wire from my battery to my power wire to amp basically blows every couple months or so. So what should I do? I'm running 2 gauge towards my battery but all my wires connected to my amp and cap is 8 gauge wire. Everything is stock but with that much power should I just get a second battery VS A cap. If so what kinda battery or cap should I consider buying that's not too perfect for my set up so far? Also should I do the big three just to do it or no? I just wanna be able to eat the most out of these subwoofer and I feel like I'm really not getting as much powere as they can handle.
Buck Pomerantz from Crutchfield
Posted on 6/13/2017Eric, I doubt a Big Three upgrade will fix your light-dimming issue, but it certainly wouldn't hurt to do one. First, I'd check the battery and then the power and ground wiring for any weaknesses. If that doesn't fix things then maybe a capacitor would work in your situation.
Eric from Garfield Heights
Posted on 6/12/2017Hello Buck, let me cut to the question so i won't waste you're valuable time. I have a 2005 Scion Tc Electrical upgrades : 175 amp Alternator and an XS power D2400 with no big 3 upgrade. Personal upgrades : 2 12 inch American bass XFL1244 powered by a Hifonics BRX1516.1d at 1 ohm or 1500 watts rms My question is do i absolutely have to upgrade my Big three now that i have the HO alternator? I have slight headlight dimming and voltage drop from 13.3 to 13.1. Should i be afraid of frying my vehicles computers? Oh, did i mention my voltage at the battery charging is 13.3 with nothing on! Thanks in advance!
Buck Pomerantz from Crutchfield
Posted on 5/1/2017Matthew, If you want a question answered about a system, you must identify the equipment by model numbers as well as brand names. Without knowing the subs' impedances, I can't tell how they can be wired to an amp or what power output and draw would result.
Matthew from Wichita Falls, texas
Posted on 5/1/2017Crutchfield, I'm super impressed with your dedication to your customers ! Please help me, for I am a young Padawan. I am wanting to put 2 subwoofers 500rms each, and four door speakers 80rms each. (All are alpine type s) I'll have two alpine amps type d 500 watts(one to each sub), and one alpine amp 300 watt type d(for door speakers). I'm pretty afraid the 1300 watts is gonna kill my alternator. I have a 2014 chevy sonic, not super fancy. Do you think 1300 watts is a little much for the stock electrical system?
Buck Pomerantz from Crutchfield
Posted on 4/13/2017Sage, That amplifier should not be a burden to your vehicle's charging system or a cause of burnt-out bulbs. Maybe it has a loose power or ground connection. Turn the stereo and amp off and take your car to a service shop to have someone check the electrical system, battery and alternator. That sounds like your main issues.
Sage from Long Beach
Posted on 4/13/2017Super helpful post. I have a few questions! I am running two 10" Boston Aucoustic subs with a GT2 125 amp in my 2012 Mazda3... with a stock battery and alternator :( I've had the dimming lights for awhile and not only that, I've replaced shattered and burnt bulbs time and time again. Recently my car hasn't been starting as fast and turning over. And now I know for certain my alternator is failing. I'm sorry if this is a stupid question, I'm learning as I go... until I can upgrade my alternator and or get a capacitor should I go to the trouble to remove the wiring as well... (as I'm not sure if they have anything to do with the possible short that's making my head lights shatter) or can I just disconnect them from my amp and subs and be alright? And is my alternator permanately damaged and going to continue to fail even without the extra pull for power?
Buck Pomerantz from Crutchfield
Posted on 4/11/2017Joe, That massive amplifier will try and draw about 120 amperes of current while working, 300 amperes on musical peaks. This is a lot more than what most stock alternators can put out. Generally you can expect to be able to use half of your alternator's amperage capacity for aftermarket equipment like amplifiers. A second battery will help a little, but ultimately you may find you need a beefier alternator.
Joe from Tupelo
Posted on 4/11/2017I've already done a 1/0 big 3 upgrade for a previous system but only used 4 gauge for the amp. Im about to upgrade those to 1/0 because im wanting to run 2 skar audio ZVXv2 15"s (1500 rms each) on a skar SK3500v2 (specs say 3800 rms @ 1 ohm)....if I had a good enough second battery, could I manage with a stock alternator still? Any advice would be appreciated. Thanks
Buck Pomerantz from Crutchfield
Posted on 4/10/2017Zac, Not knowing exactly what amplifiers or subwoofers you have make it impossible to give advice on the system they're in. If you want a question answered about your system, you must identify your equipment by brand names and model numbers.
Zac from Sherman
Posted on 4/9/2017Just picked up a few things for my 1985 nissan 720 two 10" 1050 rms each runing from a 4000 watt mono block one 8" 500 rms and 2 4x10" 150 rms each running from a 1000 watt duel chl for my highs i have 2 6.5" 125 rms each and 2 1" tweeters running from a 200 watt duel chl should i go ahead and pick up and 2nd battery and a copacitor already got all the wires for the big 3 but my stock alt is 60 amp looking in too a gm swap for a 120 amp any help would be awesome
Buck Pomerantz from Crutchfield
Posted on 4/6/2017Dustin, A rule of thumb about a vehicle alternator is that 50% of its current capacity is available for non-automotive use, like car amplifiers. The 80-amps of available current in your vehicle will probably easily support your two amplifiers, especially if they use efficient Class D amp technology. As long as your amplifiers have adequate power and ground wiring, I don't see that you'll have any power supply issues. You should only consider getting a capacitor until after you detect slight light-dimming with loud music.
Dustin Zysset from Columbus
Posted on 4/5/2017I have a 2006 chevy tahoe with stock bose. I'm putting in one 13.5 in jl audio tw5 2 ohm which is 600 watt rms and I'm putting a 500 watt rms jl audio amp to power it, I'm also planning to replace the door speakers and use a 250 watt rms amp to run those, and putting in a new head unit. Its not hooked up yet so i don't know if lights will dim, but im trying to plan ahead I'm going to upgrade my big 3 regardless because i feel like it's going to be a good idea, i also plan to get a yellow top optima battery for the vehicle, i got to looking and found out i have a 160 amp alternator already installed. Now my question is after i get the better battery and upgrade my big 3 and get my stereo in do you think Im going to have to upgrade my alternator or should i be ok? Also should i get a capacitor or will i be ok without it? Thanks in advance for your help.
Buck Pomerantz from Crutchfield
Posted on 3/31/2017Travis, It sounds to me like you may benefit with a Big Three upgrade when you replace the alternator, augmenting the existing electrical wiring with larger gauge wires. The auto mechanic who will replace the alternator may recommend upgrading the wiring as well.
Travis
Posted on 3/31/2017So, I have a 1981 GMC C1500 pickup, I'm currently installing a new stereo in. I'll be using a Pioneer 7800BHS head unit, Kenwood XR900-5 5-channel amp, running 2 Pioneer TS-SW2502S4 10" subwoofers wired in parallel to a 2-ohm load, Focal PS 130 V in my doors, and some 4" Alpine 2-ways in the cab corners just for the time being. The truck originally has a 63-amp alternator, I'm swapping in a 105-amp later model one, and I'd like to wire everything up as correctly as possible, the factory wiring runs through 10 gauge wiring on the charging system with a few fusible links, am I able to leave this in place and simply run a larger gauge (and fused) wire to the battery, or am I going to need to rewire the entire charging system? As it stands, the factory wiring comes off the alternator, goes to a junction block on the firewall and goes to the + side of the starter, which has a 4 gauge wire going from the starter + to the + terminal on the battery. Thanks in advance. Side note, the amp is going to be wired up using 4 gauge OFC positive and ground, 10 gauge for the subs as they are the big draw, and 16 gauge to the speakers, all OFC, with amp power wire fused near battery with a 125amp fuse.
Buck Pomerantz from Crutchfield
Posted on 2/28/2017Ryan, You didn't say what Class amps you want to run, but whichever, assuming a 13.8-volt system, achieving 5000 watts RMS will take 453 amperes for a D-Class amp, and 725 amperes for an A/B amplifier. If you're bumping tones, I don't think there's a single alternator in existence that can handle that much current, so running multiple alternators plus multiple batteries sounds like your solution. For playing music however, when the duty cycle of the amp is more like a third of peak current draw, it might work with just one high-output alternator and a second battery, like an XS Power XP3000.
Ryan from Saint Louis
Posted on 2/26/2017Quick questions on electrical. Planning to run 4.5k rms to two 15s, and then about 500 rms to door speakers. Thoughts are throwing 2 batteries in the trunk and upgrading to a 250 amp alt, or adding another alt along with my current 200 amp HO alt. Big 3 is already done and will probably run a couple runs of 0 gauge. Do you think this would be sufficient enough to run 5k? Also any suggestions on batteries? Thinking maybe 2 XP3000s. Thanks for everything.
Buck Pomerantz from Crutchfield
Posted on 2/20/2017Rob, Let's do the math for your car: A 160-A alternator will have 80-A available for non-automotive use. An 80-A draw at 13.8 volts results in 1104 watts RMS for a perfect amplifier and 552 watts RMS for a typical 50% efficient AB amplifier. So, it looks like your 400 total watts RMS amplifier will pose no issues, as long as it's installed correctly.
Rob from Chesapeake
Posted on 2/18/2017Hello, I am looking into upgrading my system in my 2008 Chrysler 300. I am looking at replacing the four stock speakers with Kicker 6x9 3 ways 150RMS, along with adding a Pioneer deck, and using a MB Quart 4 ch 800 watt (100RMS per channel) amp to drive the four Kickers. I have no subs or additional speakers in the car. I would like to know opinions or facts as to whether or not I should be worried about having to change the alternator to a higher output. I hope I do not obviously, and reading the setups others are using here on this forum makes my system sound small in comparison. I have looked up the specs on the 300's stock alternator and it appears to be 160 amps. Give me good news lol...
Buck Pomerantz from Crutchfield
Posted on 2/14/2017EB, I'd listen to my installer and not cause issues with that wire or the alternator. You should take your vehicle back to him and see if the light-dimming issue can be resolved.
Buck Pomerantz from Crutchfield
Posted on 2/13/2017Eugenio, You might want to wait and see if the amp causes any electrical overdrawing issues before putting in a high-output alternator.
Buck Pomerantz from Crutchfield
Posted on 2/13/2017Teo, It sounds like you may have your two subs wired out of phase from each other, but if you like the sound, go for it.
E.B. from Louisburg
Posted on 2/13/2017I recently took my vehicle to my local stereo Shop and they did and upgrade to my negative wires. I thought it was the Big 3 upgrade, but they didn't replace or did anything to the alternator hot wire. They said in there past experience, when the replace the factory hot wire that I could cause issues, so they did 4 gauge ground wire from battery to chassis, battery to alternator, then 8 gauge wire from battery to body, which is the factory ground wires. I currently have changed the battery to a yellow top optima and I have 4 gauge hot and ground wires running to a distribution box the from the distribution box to my amp is 8 Guage wire, cause my amp will only accept no larger than 8 Guage wire. So with all that said and my headlightson dim a little still, but adding all these additions helped, should they have installed the hot wire from the battery to the alternator, a new wire, but still kept the factory hot wire? Thank You!
Eugenio garza from Fremont
Posted on 2/12/2017I have 2 12" solo baric 2 ohm at 50-750 watts rms each and am going to order a kicker CXA1800.1 mono amp at 1800 watts rms @ 2 ohms, i read that the amp can draw some serious amounts of current (up to 163 amps) and i was wondering if i should just go ahead and get a hight output aftermarket alternator.
Buck Pomerantz from Crutchfield
Posted on 1/13/2017Anthony, If you expect your alternator to output up to 240 amps, you will need to use Big Three wiring and a fuse that can handle that much current.
anthony from aubur
Posted on 1/13/2017hey i have a 2004 mitsubushi eclipse with a new optima red top battery, and recently purchased a 240 amp h/o alternator along with a big 3 upgrade kit. my question is is do i need a new inline fuse between the alt and the battery? the inline fuse already there is only rated for 120 amps
Buck Pomerantz from Crutchfield
Posted on 1/4/2017Mike, I recommend going back to your installer, show them the problem, and see if they can offer a simple solution, like tightening connections or adding a capacitor. An audio system this size should not overpower your vehicle's charging system.
Mike from Poland
Posted on 1/3/2017Hi! I have a 2014 Honda with a 95a alternator. There is only one amp driving the system right now and i already experience dimming when the bass kicks while the car stays on idle. The amp is a mbquart running about 2x85 to the fronts and a bridge of about 260 watts to the 10 inch sub. Wiring was done by a pro and everything is set up for an additional jlaudio 600/1 which i already have but not connected as i noticed the dimming (lights on, idle rpm, no other power drains like heated mirrors or seats etc. - just the lights and aircon). As you probably noticed the power drain from what i have now is not something substantial and the car has a special battery (80ah agm for start/stop usage). The vehicle is pretty new and has about 30k miles on it. What would you recommend?
Buck Pomerantz from Crutchfield
Posted on 1/3/2017Lorenzo, If you've already checked over and ensured good connectivity with the proper-size power and ground wires and the battery checks out as well, you may very well benefit from adding a second battery or replacing the alternator with a higher output version.
Lorenzo from Richmond Virginia
Posted on 1/1/2017Okay so I have a 2015 Dodge Charger SE. I have 4 Rockford fosgate 169 prime 3 way door speakers hooked up to a power T-400 4 channel amp. I have two Rockford fosgate P3's hooked up to a power T-1000 amp. When playing everything is fine up to about volume 15. Anything above that and the battery volts drop from 14.5 to anywhere between 11.5 and 12.5 and sometimes depend on the song below 11.5. So my question then becomes do I need an extra battery, do I need to replace the current car battery with a bigger one, should I do the big three or should I replace the alternator?
Buck Pomerantz from Crutchfield
Posted on 12/28/2016Joe, I recommend going back to your installer, show them the problem, and see if they can offer a simple solution, like tightening connections or adding a capacitor. An audio system this size shouldn't overpower your vehicle's charging system.
Buck Pomerantz from Crutchfield
Posted on 12/28/2016Casey, I hope you're not adjusting the amp gain on the fly. Gain should be set once and then left alone. If you have a Hifonics Brutus BRX2000.1D, it calls for 2-gauge power and ground wire. And if you plan on adding another amplifier later, you should put in 1/0-gauge wiring. But this size system will likely overwhelm any vehicle's factory charging system. The mono amp alone, wired to a 2-ohm load, will put out up to 1400 watts RMS, drawing up to 127 amperes from the electrical system. So, larger wiring, new battery, second battery, HO alternator: these are the solutions you should be looking at.
Joe cita from Milwaukee
Posted on 12/27/2016I have a 2012 Toyota Camery V6 SE. I had it upgraded to get full range from a pair of Hertz milipros in the doors and a set of same 6X9 in the rear deck. With an alpine sweep 10dr subwoofer, running through a pox alpine 5 channel amp. 75w x 4 to the doors and rear deck 300w to the subwoofer. I have 2 jl cr 350x inthe dash, not hooked to the alpine. The head lights slightly flicker when the sub hits. I upgraded the battery to a deep cycle with reserve (x2 bakttery from batteries plus). I plan to replace exterior lights with led, not the headlights, fogs turns signal etc), but the amp decrease will be minimal. The flicker is slight, and the batterybhelped but did not eliminate the flicker. The stereo pulls more than stock but based on set ups on threads is not pulling a ton of power.al professionally installed by the best reviewed installer in se Wisconsin. Would a big 3 upgrade be the recommended course? A higher output alternator seems like it would be overkill?
Casey Woody from Kingston, TN
Posted on 12/27/2016I have a 2004 Mitsubishi Lancer Ralliart. I have a stock alternator. My system is a 12" Alpine type x In a huge ported box made by fatbox. (The box really set the sub off! Tuned at 30.2 Very low bass) I also have a 2000 watt Hifonics Brutus 1 channel mono block. I also have a 3 farad Power Acoustik capacitor. I have everything wired to 2 ohms. I think I'm probably passing right around 1000 watts rms. I wired the system up with 4 gauge wire and speaker wire is 10. Also running with a sony head unit. I am going to do the big three upgrade, but here is my question. My lights dim at night. I find when I really start to push the amp ( I have the gain on my amp set to about 2/3) and during the day I can run my gain at about 2/3 which is the max I run because after that I notice clipping. But at night, if I turn my bass knob past the half way point, that is usually where I see the lights starting to dim. I'm looking into a h.o. alternator right now but needing to know which one I should do first. Big three or alternator? I plan on upgrading my component front speakers and rear speakers and push them with like a 5 or 600 watt amp as well. I know that my battery is 5 years old and might actually give out on me anytime. So I need to know about the big three or alternator first. I can find a 180 or 200 watt alt for my car for a decent price. And also, what battery, decent priced, do you suggest. I hope I have given you enough info because I want to get this figured out quickly. Thanks!
Buck Pomerantz from Crutchfield
Posted on 12/19/2016Adam, I suggest you wait until after your amplifier and subwoofer are installed, and after you start experiencing headlight dimming before you do any electrical system upgrade. There's no point in preparing to fix something that may not be broken.
Adam from Nashua
Posted on 12/19/2016Hello, I have a 2002 Subaru WRX and am planning on getting a Alpine type-r 10 inch sub and a alpine MRX-M110 amp. Will my car be able to handle this? Or should I get a capacitor or high-out put alternator? I also have a radar detector which is plugged into my cigarette lighter. Thanks
Buck Pomerantz from Crutchfield
Posted on 12/16/2016Brian, It's unusual for such a low-power system to cause light-dimming. Like the article says, the first thing you should do is make sure all the surfaces used in power and ground connections are scraped down to bare metal, clean, and all the connectors and the battery terminals fastened tightly together. And check the battery itself. If you still have dimming after that, you should consider adding a capacitor or second battery or a wiring upgrade to your system.
Brian from Cleveland
Posted on 12/16/2016Hey Buck, I had a kicker zr360 and 2 Orion xtpro122 connected and my lights dimmed even while accelerating on the highway. Since, it has been disconnected and I am going to connect a zr600 which I believe definitely will not help. What would be the best addition to address the dimming lights? Should these be wired a specific way? Thanks in advance!
Buck Pomerantz from Crutchfield
Posted on 12/13/2016Salih, Like the article says, the first thing you should do is make sure all the surfaces used in power and ground connections are scraped down to bare metal, clean, and all the connectors and the battery terminals fastened tightly together, Then you'd ensure that the battery checks out as well. If you still have dimming, then you may very well benefit from replacing the alternator with a higher output version.
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