working with a weak electrical system

[THATpurpleKUSH 5,000+ posts]

I install audio gear for my friends and a buddy with a 96 Civic wants me to put in 2 amps that will run about 800wrms in total. The only problem is that from what I have seen, the stock alternator is 70amps. I have never had to deal with such a weak electrical system. What should I do to make sure it's adequate to power everything? Big 3 upgrade and a cap? Thanks.

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[IBmikexxx 10+ year member]

I'm running a 98 civic, so I've got the same electrical system and I'll be running around the same rms. Can someone shed some light on this, cause I'm mid research on how I can make sure my electrical is sufficient. I know a HO alt would probably do the trick, but thats probably the pricier of options. Anything good to solve the matter at hand?

 

[ahole-ic]

Everyone is going to say ditch the cap and go with batts... Don't listen to them just ditch the cap don't get a batt. Do the Big 3 with wires as short as possible and run power wire as short as possible. Ground directly to the frame. Then set the gain with a dmm and be Conservative. Just because the amps are capable of 800w doesn't mean they have to put that out. You'll get better sound if the amps have clean power than turning the gain up and getting dirty power.

 

[IBmikexxx 10+ year member]

True. I got the big 3 ran in 1/0 right now, but I could for sure run a new bat under the hood, and also throw one in the back. I just don't want to do that if I'm still looking at having a problem. If thats the case, I'll just have to go ahead and grab a HO alt. I just don't want to over due it either.

 

[IBmikexxx 10+ year member]

I'm going to re-do some of my grounds first and make sure thats not part of what causes my headlights to dim, but then from they're I'll probably run a better wiring kit, and possibly a battery to the trunk.

 

[ahole-ic]

I'm going to re-do some of my grounds first and make sure thats not part of what causes my headlights to dim, but then from they're I'll probably run a better wiring kit, and possibly a battery to the trunk.

A Battery cannot STOP your dimming. It can reduce it if your voltage was previously dropping below 12.6v. The dimming usually comes into play when the alternator cannot keep up and the voltage drops from ~14 to 12.6. Adding a million batteries will not raise your system voltage. The only thing you can do without adding a high output alternator is reduce the resistance of your electrical system as much as you can. Batteries ADD resistance. That's why they have ESR ratings. If you replace your battery up front with a low ESR battery you have done as much as you can battery wise.

There are some funny arguments here. Here is an example of the argument. Since 2 - 4 ohm resistors wired in parallel shows a final resistance of 2 ohms (4 divided by 2) then 2 batteries will have half the resistance of 1. This couldn't more more far from the truth. Does wiring the batteries in parallel make them easier to charge? No of course not. ESR does not equal actual series resistance. The only 2 reasons to ever add batteries in the back is to be near the amplifiers to prevent the voltage drop incurred by the power wire and grounds and to keep the amplifier's voltage above 12v. The other is if you like to play your stereo with the engine off and you buy an isolator.

 

[IBmikexxx 10+ year member]

Well I'm currently running off of a Walmart Battery, so I could probably see a nice increase going to a yellow top or Kinetik battery.

 

[bubbagumper6 5,000+ posts]

Honestly, with only 800wrms, you should be fine just upgrading the hood battery and doing the big 3. Once you cross that 1kw line though, I'd look into at least a second battery, and possibly even a better alt.

 

[IBmikexxx 10+ year member]

Well the big 3 is done and I still got my lights dimming. I would say since I have a shitty battery though, going to a low ESR battery would probably make a good difference for me. And even if I decide to go HO Alt, I'll probably want to get rid of the current battery so why not start with upgrading that.

 

[bubbagumper6 5,000+ posts]

Well the big 3 is done and I still got my lights dimming. I would say since I have a shitty battery though, going to a low ESR battery would probably make a good difference for me. And even if I decide to go HO Alt, I'll probably want to get rid of the current battery so why not start with upgrading that.

I don't really understand why people think the big 3 is a solution to dimming...it can actually make it worse. I mean you get dimming because your amplifier is pulling more current than your system can handle, so you get a voltage drop. Increasing the size of your wires can make it easier for the amp to pull more current and thus make the voltage drop more...

 

[hornedfrog1985 5,000+ posts]

I do poo

 

[ahole-ic]

I don't really understand why people think the big 3 is a solution to dimming...it can actually make it worse. I mean you get dimming because your amplifier is pulling more current than your system can handle, so you get a voltage drop. Increasing the size of your wires can make it easier for the amp to pull more current and thus make the voltage drop more...

Maybe this will help you understand. I'll tell you how I first discovered the "Big 3". My first install many years ago when I was 16 had horrible dimming. I took my high school electronics (at the time) education outside to try and figure it out. Living at home and having a decent paying job gave me expendable income, so I had extra wire. I looked and found a 10 foot 10 gauge wire connecting my battery to my vehicle's chassis. This meant that all current that was drawn throughout the entire electrical system was going through 1 piece of 10 gauge. I didn't want to cut it because it was connected in this boot at the battery. The same goes for my alt to batt charging wire. I upgraded these two and my dimming was nearly gone. It's because the huge resistance those stock wires have under heavy draw don't allow the headlights to draw the current they need.

So you're looking at is as, people who have too small of an alternator need not allow their amps to draw any MORE current by doing the big 3. I look at is as, almost EVERYONE has too small of an alternator for their stereo, but the big 3 allows us to eek out as much current as we possibly can by reducing resistance.

We both have points. Nobody is wrong or right here although if all wiring is done properly I only run this risk of blowing up my alt. You run the risk of popping fuses or burning your car down due to too small of wire.

 

[bubbagumper6 5,000+ posts]

Maybe this will help you understand. I'll tell you how I first discovered the "Big 3". My first install many years ago when I was 16 had horrible dimming. I took my high school electronics (at the time) education outside to try and figure it out. Living at home and having a decent paying job gave me expendable income, so I had extra wire. I looked and found a 10 foot 10 gauge wire connecting my battery to my vehicle's chassis. This meant that all current that was drawn throughout the entire electrical system was going through 1 piece of 10 gauge. I didn't want to cut it because it was connected in this boot at the battery. The same goes for my alt to batt charging wire. I upgraded these two and my dimming was nearly gone. It's because the huge resistance those stock wires have under heavy draw don't allow the headlights to draw the current they need.
So you're looking at is as, people who have too small of an alternator need not allow their amps to draw any MORE current by doing the big 3. I look at is as, almost EVERYONE has too small of an alternator for their stereo, but the big 3 allows us to eek out as much current as we possibly can by reducing resistance.

We both have points. Nobody is wrong or right here although if all wiring is done properly I only run this risk of blowing up my alt. You run the risk of popping fuses or burning your car down due to too small of wire.

Yeah, I agree. I said it can increase dimming, I didn't say it always did. It just depends on why your getting dimming to begin with. I did it on my original car and made my dimming worse. Upgrading the rest of the electrical system (batteries & alt) fixed it though

 

[legendndisguise 10+ year member]

Pretty much everyone has a good point. I would start with a battery and alternator upgrade. If the system is truly putting out 800wrms, and figure the voltage is roughly 13.8V, you will be pulling close to 60 amps. You have already stated that the stock alt is only a 70 amp alt. You will be putting a strain on the electrical system, battery would probably fail first and then the alt. I would assume that when installing the amps you will be using proper wire size and grounding for clean flow. There is an eBay store that I bought a rebuilt alt from that put out more current for my vehicle now and have had no problems in the past year. The sellers name is "more_amps", and they are fairly cheap. I have an alternator that was on my 99 Civic Si a few years ago and was putting out 130 amps that is just sitting around. I am not sure if it will fit a 96 or not, but if your friend wants it shoot me a pm, I will let it go cheap and have it tested before hand.

 

[MustangGT25YRS 10+ year member]

Hello/

I have a *1998/Saturn SC2*.It comes w/a 90-95 Amp Alternator.I did all of theUnder Hood

Connections with *1/0 Red & Black TryStar Welding Cable* from the E/Bay Store:Coppercableman.

I even upgraded the Alt Cable to 1/0.I had enough cable and wanted to make sure anywhere

I could upgrade Power & Ground Cables,I did.../;O].

I have 2/Old School Kicker ZR Amps.One is a ZR/600 for the *CDT ES Front Stage* with 6.5 Subs

from them.They are 2 X150 @4/Ohm Stereo.But it's probably around 2X175 @ 4/Ohms Stereo.

The second is the ZR/1000 @1225 Watts Bridged Mono @ 4/Ohms to 2/Eclipse 88120 Subs.

So I have approx. 1575 Watts Total RMS.They have 4/Gauge Red & Black Welding Cable

for power & ground,plus an 8/Gauge Remote Cable for each amp.

I have very little dimming in my headlights.Yes it was alot of work,but am very happy that I've

had *No Issues* w/my 90-95 alternator.I can't remember if it's 90 or 95 Amp right now.

IMOPO,I believe it did really help me.I can't stress enough trhat *Proper Termination* of the

cable lugs is *Very Important*.And I highly recommend the use of *Adhesive Dual Wall Shrink Tube*.

Yes,It costs alittle more but it rewards you*10/Fold* down the road!!!.Done properly,there will

be NO:*Moisture* getting into the cable & lug connection.NO: Dirt/Road Salt/Etc. getting in it

either.and is 100/Times better than Electrical Tape,I've had:*Zero Electrical Problems* since

approximately 2006.Also...*Use High Quality Cable Ties and Route Neatly and Securely*!!

Use *Heavy Duty Black Cable Ties* w/120 Lbs.Tensile Strength[Written On Package Lable],when

doing the 1/0 Cable,under your hood.Use Loom or Good,tright Weave Expandable Sleeving.

You can get it on E/Bay at a Store called:Furryletters.Great Prices and a Nice Man.Type in:

*Expandable Sleeving*.Check that small box too,under that heading.

I hope this can help you and I'm not criticizing you or anyone else here/=O].You,If Done Right

*Will Not* have to look back and say"I should've gone a few extra $$$ and bought better materials".

Take Care and *The Best Of Luck* w/your system.../;O].

Best Regards/

Raymond