alt differences?

[Gmc-76]

I have an 85 c10 with a 305. I replaced the factory alternator with a "higher amperage" factory one from advance auto. I have 2 amps and 3 12' subwoofers in my truck, and they draw a lot of power from the alternator. What is a good alt upgrade? Tired of the lights dimming every time I listen to the radio.

[reporter000001]

I had the same problem, I just taped into the wiring and put thelights on a relay off the bat. probem solved.
Its a ton of work but just uping the amperage wont fix the dimming, Ive tried it.

[Gmc-76]

Originally Posted by reporter000001

I had the same problem, I just taped into the wiring and put thelights on a relay off the bat. probem solved.
Its a ton of work but just uping the amperage wont fix the dimming, Ive tried it.

thanks for the reply, do you possibly have any pics of the relay in the headlight harness?

[reporter000001]

no i dont,i just used a standard "hella" relay with the tab on them to screw them into steetmetal, i used the factory tan and brown??? wire leads to tell the relay to turn on... dont quote me on those colors, any ways.....heres some people that did a similar job.... http://67-72chevytrucks.com/vboard/s...eadlight+relay

[rich weyand]

I bought a relay harness from these guys and just plugged it in. Five minutes, and no wiring changes. I bought the 9003 for my '78 with the two 7" round headlamps. $25.

People have told me "Oh, those kits use cheap relays" and then they do a ton of work to accomplish the same thing, but this kit has been on the truck for 2-3 years with no problems.

On this page, there is a ton of stuff, so do a "Find" on "9003", and the third hit will take you to the relay harnesses.
http://www.autolumination.com/headlights.htm

[wilkin250r]

What's happening is that you're getting a voltage drop when your subs hit. Just like music isn't a constant volume, the power that your amps pull isn't constant either, it pulls a sudden surge of power from your system when it pushes your subs really hard. That sudden surge of energy causes the voltage in your entire system to drop.

You've probably already figured that out. What you may not know is the subtle nuances of electricity. I happen to be an expert in that area (I'm an electrical engineer).

Ever look at battery specs? They list Cold Cranking Amps, typically 800-1000. That means your battery is capable of supplying 800A*12V = 8600watts!!! And it can do this all on it's own, even without the help of the alternator, it just can't do it forever, it will eventually go dead. But you're not having dead battery problems, right?

So if the battery is capable of pushing 8600 watts, why are the lights dimming when my amps are pulling a mere 2000, less than a quarter of what the battery can supply? The answer is that the problem isn't in your source of electricy, it's NOT in your alternator and battery. Upgrading those won't do much good.

The problem is in your wiring, and voltage drops and losses in wires that are 30yrs old and weren't designed for high-power audio to begin with. THAT'S the part you need to upgrade to keep those voltage drops under control.

I'm thinking a large capacitor on your power wires to your amp will solve your problem. The capacitor will store energy. It holds less than a battery, but it will release it faster and better. It will release it's energy when your subs hit, and recharge between hits, and is specifically designed to reduce voltage drops in large-power audio systems.

Something like this should work nicely. http://www.crutchfield.com/p_1203DDC...Capacitor.html

[rich weyand]

That's one way. The other way is to run a separate wire directly from the battery to the subs' amp. I ran an 8AWG wire from the battery to my subwoofer. It has it's own in-line fuse at the battery. So I don't use any of the wiring that was in the truck to run the sub.

[reporter000001]

im sure he has an amp install kit already nobody is dumb enough to wire the amp using the fuse box...

the headlings get power from the 12red splice. the box and everyaccesory gets power from the 12red incoming off the firewall.

Maybe your system dosent draw enough power to show a voltage drop at the fusebox.....i wish i could ost a video of back in 2009 while playing a cd my afermarket guage showed 10v at the fusebox when a 40Hz wave longer than2 seconds dumpedddddddddddd.

that was 6g wire to 2 12in dvc's on a 500watt amp....a true 500watts.....not that walmart claimed "1500000 watts!!!!!"
It was straight off the battery and grounded to FRAME. battery was a 4yo costco. alt was a cheap-o pepboys 3pole 80-100amp... idk....
when subbin hard the lights dimed noticeably and if heat fan was on, even it would buzz around.

im telling ya, its a 30+ old system, with new technlogy in it..... im sure new wires new bat and new alt would be great....but if your drawing some serious power from a clean system,like 2 15 fosgates on a 1ohm bridge..... that amps gonna bbbbrrreeaaatthhhheeeee and the lights will show it...


so i repeat..... just wire the lights off 2 relays, 1 highs, 1 low......directoff battery or off junction block, use nice 12-16g wire.... problems solved. Ive done it, if u have the money a NEW not not not rebuilt alt would be awesome, but relays are cheaper......

i changed my entire wiring system because of this, im now using 2batts on a remote trunk kit, 100a high vent fan on alt, charging post off alt to my underhood junction/starter point, amp and truck off there...... lights NOT thrugh switch, now off relays fed with 2 fused 8g wires 1 high 1 low off junction oint......
i spent 6 months drawing diagrams and doing research...... the charging system on these trucks makes sense, but is inferrior to new methods.........if you do your research.

in addition,my Sylvania's are now white/blue and not puke yellow,

a capicitor aka cap is alway a good idea, but its like xanax for your condition..... it will just mellowout the dims. idk what kind of amp and system ur using, but if its "bugging" you u prob spent some good money, and is going to draw no matter where it comes from, a quick dumping 2farad cap or 2 batterys parallel.

i went to school with 2 guys into sterios, one was a 4 alternator 1bat chevy cab through 4 fosgate 15's......he had over 10 sound violations....... another was a chevy s10 and that had 2alts, 1 bat, a cap, and a small motorcycle battery feeding the cap allllll in hopes to stop voltage drops and supply a CLEAN steady 12-15v dc...

both of them with that song by......2-short would hit so hard, the cd player would sense too much of a drop and shutdown..then it would regain current and restart..... and shut off.......

a CLEAN "noise free" charging system and good cables can make a 100 doller system sound like a 500 doller system......i spend 125 with tax at bestbuy in 2006 on an open box and it blows peoples minds to this day. eminem guess whos back and an unknown artist with the song "i oly love you hen were f***ing" turns heads everywhere i go.... i once drove for 3 miles before i noticed the cobs behind me, thought i was running when i just couldent hear them, it was a 1way road and alls they wanted to da was pass me haahah

[69heavychevy]

I'm no stereo expert but I'll share the set up I had in my old 69 that worked great IMO...
First thing I did was do the headlight relay upgrade. There's plenty of write ups on the net on how to do this, or you could just buy a kit.
Next I upgraded to a CS130 alternator (90's GM alt). There's plenty of write ups on how to this as well. Mainly requires splicing in a resistor if you don't have idiot lights.
Then I bought me a yellow top optima. I got lucky and was able to get one of the last Aurora made ones. There made in Mexico now and there quality has suffered. My optima is 8 years old and still ticking...
My set up consisted of a comp. Audiobahn 12" Cant remember exactly which model, but it was rated at 1000W. It was powered by a 800W mono amp. My 4 door speakers were powered by a 600W amp.
I never had any dimming of my lights and my gauge read at a steady 14V. I would get a small amount of voltage drop when standing at a stop light with the bass at max. Based on my gauge it would drop to around 13.6-.8. But like I said that was with the stereo at full blast with all lights on.
The only thing I would do different for your set up is get a good capacitor and maybe go with a CS144 alt.

[king-918]

Originally Posted by Gmc-76

I have an 85 c10 with a 305. I replaced the factory alternator with a "higher amperage" factory one from advance auto. I have 2 amps and 3 12' subwoofers in my truck, and they draw a lot of power from the alternator. What is a good alt upgrade? Tired of the lights dimming every time I listen to the radio.

You need to get one built like from Singer or Irragi

[king-918]

Also what amps are you running and how many amp hours are your batteries

[Tdubbyount]

I run relay harnesses from classic industries. Replaced my alt with a power master 200 amp, no dimming issues even when I've got my 4 kc's on. I run 2 amps with a 12 inch sub. A little over 1000 watts rms between the two.

[enaberif]

CS130 (105a) is one of the easiest upgrades to higher amps.

CS140 (140a) is another alternative which takes a bit more work but nothing dramatic.

Both will also require an adapter which you can get at Napa .. ECH EC80 and EC82. The EC82 has the resistor.

[king-918]

What amps do you have?