The “Big 3″ is a very easy mod to your car’s electrical system that will help it maintain higher voltages for more power hungry amplifiers. If you’ve ever measured your voltage drop when playing music with the volume to the max with your engine running, you’ll see that instead of reading 14.4v or 13.8 (depending on car), your voltmeter will read 13v, 12v, or even lower! You can easily tell if you’re experiencing these voltage drops by watching your headlights. If they dim while playing your system, you most definitely have voltage drop going on. This voltage drop could potentially cause harm to your amp if it is significant enough. I had a Treo SSX 1500.1 blow because I was letting my voltage drop to about 9-10v, which the amp didn’t like very much.
What causes this problem are the stock, small gauge wires used to connect various electrical components. The stock wire is usually 8 gauge, which is sufficient enough for roughly 50 amps. Large amplifiers can pull up and over 200-300amps, so now you see the problem.
When doing this mod, 3 runs of wire will need to be installed. They are:
- Battery positive (+) to alternator – From the positive terminal on your battery to the alternator positive (+) post
- Engine block to chassis ground – From engine block to chasis. This is to strengthen the ground.
- Battery ground (-) to chassis ground – From the negative terminal on your battery to your car’s chassis.
Here’s a picture of the “big 3″ when completed. The colored lines correspond to the colors of the description listed above.
I recommend using 1/0 gauge wire. You could use 4 gauge wire if that’s all you have laying around, but you might as well use 1/0 the first time so you won’t have to go back if you decide to upgrade your system later on down the road. The wire I used was Knu Konceptz 1/0 Kollosus Kable You will also need 1/0 ring terminals to terminate the ends of the wire.
Before you do anything, make sure to be safe. Disconnect the wire from the negative terminal of your battery before you begin. This makes an incomplete circuit and keeps you safe from sustaining electrical injuries.
First, measure a length of wire to go from your battery positive (+) terminal to your alternator. Make sure to leave a little bit of slack, around 6 inches, so you’ll be able to position the cable freely. Terminate the ends of the cable with ring terminals, then connect the wire from battery positive (+) terminal to your alternator. There may be a plastic tab on the alternator post. If there is, go ahead and break it off; it’s what I had to do. If you don’t remove the plastic tab, you won’t be able to remove the nut off of the terminal post. Here’s a closeup pic of the run of wire at the alternator.
Adding a fuse to go in between the battery positive (+) and the alternator is highly recommended, but not necessary. There is a small chance that the wire will come lose and short out, but it’s a chance some people do not want to take. On the contrary, I have had no problems in the 2 years I’ve had the big 3 installed while running an unfused wire.
The next step is to run a wire from your engine block to your car’s chassis. This step may be difficult because you may have a hard time finding a place on the engine block to attach your wire. Look for a non-essential bolt; do not use a bolt that holds fluids back. Below is a close up pic of where I attached my run of wire to my engine block:
From there, you then need to attach the other end of the wire to your chassis ground location. This ground can be anywhere on your car’s chassis/frame, but make sure that you have metal-to-metal contact with the terminal and your ground location. A good start is to follow your stock ground wire back to its grounding location. If there is paint on the ground location you have chosen, you must sand it off until it is bare metal to ensure minimal electrical resistance. Below is another closeup picture, this time it is showing the ground point I used for both the engine block, as well as the battery ground.
The location is a little rusty, but you can see how I sanded off the paint until it became bare metal. The rust is because of time; I did this big 3 installation about 2 years ago. To prevent rust, use a rust inhibitor product around the contact points.
Lastly, the final step is to run a wire from your battery’s ground (-) terminal to the ground location on the chassis. Measure the wire and be sure to leave a little slack in case you need it. Then terminate the ends with ring terminals and attach one end to the negative terminal and the other to your grounding location on your chassis (as seen above).
Once you have made the new, beefier battery ground, you can cut off, disconnect, do whatever you want to the stock ground wire because it is not needed anymore. When you think you’re finished, go ahead and double check all of your connections making sure that they are snug and tight.
That’s it! The “Big 3″ is now finished. You should notice a difference in voltage when playing your system at max volume. Before I did this upgrade, my voltage was at about 10v under heavy load. After doing the “Big 3″ upgrade, my voltage under heavy load was stabilized at about 11v. Quite a large difference for how much you spent on the wire and terminals. That’s why the “Big 3″ is considered the first electrical upgrade you should do to ensure consistent power to your amplifiers.
If anybody has any questions, leave a comment and I will leave a prompt answer.
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I c that u hav a honda accord jus lik me, is it a 96 and how much power do u have,cause I two amps and my lights dim a lil bit when turned all the way up so I can imaginge when i upgrade I’m going to have trouble. An I really dont want a cap,it seems like a waste of money.
I was running an MA HK4000D. Approximately 3600-4000 watts. The big 3 helped out a lot, but I also had to get an extra battery to feed that much power. For simple headlight dimming, the big 3 is almost a sure fix.
I work for a company that has some expertise in dc/dc converters and charging systems for supercapacitors. One of the products that we manufacture is a system that is used to start commercial trucks. This system charges a bank of supercapacitors(1000 farads) to a voltage of 16-18volts. It can easily provide 3500A for several seconds with minimal voltage drop. The converter with modifications can supply 40A to keep the bank charged. Only #8 wire is needed from the battery and gnd. I wonder if there is a market for this device in High end Audio for those kooks out there that want to crank up the bass. Cost $1000
I am considering a much smaller device that has 50 farads with 35A average current output and a boosted voltage of 18V. Cost is around $160. Would the boosted voltage and the capacitor storage improve audio quality? Would the audio amps put out more power when required to do so? Would the amps run cooler improving reliablity?
Paul,
Holy **** on the commercial truck starter. 3500A at even 16v is enough to make any car audio competitor’s eyes pop out. I could see people with many amps (I’m talking 10+ 3000w amps) being interested in the setup because they only do “burps” for ~2-3 seconds at one frequency. Having that much power on tap with minimal voltage drop would be a god send, and for $1000, it’s a steal.
However, there are some draw backs that will drive a lot of people away. All the competition leagues I know of will only allow 12v batteries except for the “extreme” classes which allow anything. I think that setup above would be great for those people.
As for the smaller device, I really don’t think it would do you very good and you’d be better off with an extra battery. 35A at 18v would provide 630watts, which may be enough to run small amps, but not for larger ones. Plus, the draw on the device would suck all the power out quickly, leaving the capacitors to charge. See my post (link below) about why I do not recommend capacitors (unless they’re huge like the commercial truck starter):
http://www.isyougeekedup.com/car-audio-capacitors-are-a-waste-of-money/
The main issue is that all your amplifiers power is directly supplied by the altenator/battery. Isolated voltage from a converter ideally should be supplied to all your amps along with a large capacitance reserve(< 50farads). Boosting the voltage to 17V is good with each bass thump reducing the voltage to perhaps 14V with a complete supply voltage revovery between each beat. Music is trancient in nature and no speaker made could survive more than 100 watts on a continous basis before burning up. A higher voltage supplied to amplifiers reduces heating effects due to reduced input currents. A specialized buck/boost converter costs money along with high capacitance DL capacitors.
If you have contacts in “extreme audio” I might be able to prove this out.
to the creator of this guide, do you know the size of the bolt for the engine block where you put the 0 gauge ring? it’s the bolt in the picture, but i can’t seem to find one for my honda accord 99. thanks
I believe it is 3/8″, but it might be 1/4″. The ’99 is a different generation, but the concept is still the same. Find a non critical bolt that you can take out and put back in. Sorry I can’t give you any more detailed info.
haha, it was the 10mm bolt, found them at autozone, thanks.
i wanted to know do i add the AMP RMS and the SUB RMS to get the total of what kind of gauge wire ill be needing…i got a kicker zx1500.1 mono and a kicker solo x 2500rms/5000 peak so that means that i need a 0/1 gauge or what… please help…
Wire gauge is based on how much amperage you’re drawing. Easiest way to find out is to add up all the onboard fuses on all your amps and then use a wire large enough to carry all the current. I would do 2 runs of 1/0, one run for each amp. If the 1500.1 only has 4 gauge input, then use 0 gauge with a reducer to make it fit.
Is there a way to locate someone locally to try this?
Hello
thanks for the tutorial. I am planning to do this modification on my 2010 ford fusion (800 watt amp). Upon an initial inspection of what I’m getting myself into (kind of a novice), I reocognized both the + to alt and the – to ground wires. I believe I located the block to ground wire as well although it looked much smaller than the battery wires.
my questions are: is this wire I last referenced the correct one? is there a way to be sure? and: Should all 3 wires be removed when the new ones are put in? or is it intended that they be doubled up? I think the instructions mentioned removing only the – to ground wire, but not the other 2. Thanks
Corey, you don’t need to disconnect any of your stock wires if you don’t want to. You can simply add the 1/0 Big 3 to your existing wiring and leave your stock wiring there. It makes no difference as electricity will take the path of the least resistance. I just got rid of my stock ground wire because it was in the way.
Eric,
Is this “Big 3″ upgrade pointless if I’m going to buy an additional battery to run my system? I was going to get an Optima Red Top for the engine, and a Kinetik 2400 for the sound system itself.
Eric,
After the “Big 3″ wiring upgrade. Do i have to put an additional 4 gauge wire all the way to the trunk near the AMP for better grounding? It’s a standard size sedan with 1 or 2 AMP’s? It is necessary or just a waste of money?
LeBron – No, the Big 3 is almost mandatory for any system pushing any kind of power. It will help you out regardless.
Kinny – I’m a little unclear, but I’ll try. Are you asking if you have to ground your amps using a grounding position in the trunk? Yes, you have to. 4 gauge will be fine if that’s the largest your amp accepts, but 0 gauge is even better. If you’re asking if you need to run a ground cable all the way from your battery’s ground to your amps in the trunk, then that is totally up to you. It’s a bit more of a pain to run another cable all the way to the trunk from the engine compartment. Serious competitors do this, but for the average Joe, it’s really unnecessary.
I guess i won’t be running a cable all the way to the trunk then. I might just try if i can put in 1/0 gauge ground wire to the amps. Thanks.
i have a 93` toyota camry le. im wondering if i should do the big 3. heres what i have:
idax200
mrp-m500
12″ alpine type-r
rf punch 240×4
6022′s
sps-69c3′s
rf 1 farad digital capacitor
stock battery (duralast)
stock alt.
i am running 4 guage for my mono amp and 8 gauge for my 4-channel amp. my lights do dim. i say 1 to 10, 10 is the worst, i give it a 7. any suggestions? btw i havnt installed the cap yet.
Yes, sounds like the perfect candidate for a big 3 upgrade. Try it and you’ll probably see a noticeable improvement.
alright cool. i looked inder my hood, and it looked to confusing! is it easy? those pics of yours look so detailed and nice but with my wires it looks wierd. so 0 gauge right? any brand will do? and get a (6) 0 gauge terminal rings right?
Yes, it’s pretty easy. 0 Gauge is recommended, Knu Konceptz is a good brand, so is Kicker. 6x 0 gauge ring terminals is correct.
Just follow the guide: Positive battery to alternator, negative battery to chassis, chassis to engine block.
how long of 0 gauge should i get? can you email more for more info please? i looked under the hood of my car .. . it looks so confusing. i know that pic above looks simple and looks like everything is at the right place but my stuf is kinda wierd i dont know. i cant take pics if you want. here my email: imsooocal@yahoo.com. peace.
WTF? why did you ground the engine to the chassis, ground it directly to the battery.
how many battery terminals do u need ?
and approximetly how much feet of wire
I installed the “Big 3 Upgrade” a couple of months ago using 4G. It does make sense. The manufacturer never intended your vehicles electrical system to be used with large aftermarket amps, ect. Doing so would needlessly raise their costs.
My car, Subaru, had only 12G from battery to chassis, nothing from the alternator to battery, (2x 12G from alternator to underhood fuse box), 8G battery- to engine block, 8G engine block to firewall and a 4G Battery+ to starter. As you can see, there are some electrical bottlenecks in the design, especially the ground to chassis and lack of alternator to battery.
The improvement after the upgrade is noteworthy. No noticeable difference the first night, headlights still dimmed, but after a few days the headlights dim ONLY when bass-heavy songs are cranked to insane levels at idle. And even then the dimming was barely noticeable. Before, the headlights would dim at much lower volume levels at all RPMs. I don’t know for sure why the improvement effect was delayed. (Battery)?
The only weakness left in the electrical system are the 12G wires that feed the underhood fuse box from the battery and alt, which are the push in type from beneath. Eff-It, too difficult, they’re staying.
I retained all of the stock wiring on the car and simply piggy-backed the upgrade. My battery is an autoquest cheapie group 35 that was in the car when I bought it. The alternator puts out 85 amps max, (not at idle).
Bottom line= Recomended Upgrade