Calling all charging experts

[tobyp]

So I installed a medium sized stereo and I wanted to run a couple voltages across you all to see if i am running too small alternator, need a optima battery, etc.

I have a 110 amp alternator from a pontiac transport

I am running dual electric fans

2 fairly nice sized amplifiers

Battery in trunk with 4ga wire leading to the starter, 8 gauge to the alternator, direct from batt

I get 13.6v at idle

When the stereo starts pulling and the ac is on in traffic I am lucky to get 11v

What needs to be upgraded?

I did make sure that the stator is being excited.

 

[Jshock]

Definitely the alternator, you should get 14-14.1 volts out of a correctly performing alternator. When the stereo is pulling that much you need an alternator that can supply the power without the big drag on the system. Also, I recommend an AGM style battery (Optima quality is going down especially for the high price) because it can better handle the higher transmission of electricity. The battery acts as an accumulator/sponge when the vehicle is running absorbing voltage and current spikes, whereas your alternator is the supplier and regulator of electricity! I know they have 120amp and higher alternators in the stock configuration without having to go aftermarket!

 

[shortydoowop138]

You have a few options.. 1.) You can get your alternator respun to match the current draw.. 2.) Buy a bigger alternator.. 3.) Get a 2nd battery for the trunk & run a battery isolater btwn the 2.. That way the system runs off 1 battery & the car uses the other.. I also suggest doing a "Big 3" upgrade; battery to alternator, battery to ground, engine to ground.. Make sure ALL 3 are the same size (2-4 ga)..

Ain't nothing worse than stalling out at a light because you have the windows up, A/C on, system blasting & foot on the brake.. Bass hits & da car shuts off.. LOL Don't ask me how I know BUT you learn from experience..

 

[shortydoowop138]

Here's a link about the "big 3" upgrade.. Goes into more detail & easier to follow than what I just said..

http://www.kingofthestreet.com/forums/i ... ntry950980

 

[86 Grand prix]

That 4ga wire needs to be upgraded to at least 1/0. for a run that long the voltage drop on 4ga is not doing you any good. I would keep the 4ga for charging and add a 1/0 for the starter supply.

 

[pontiacgp]

:?:

 

[565bbchevy]

I use a 1/0 from my trunk mounted battery to a Ford solenoid near my firewall and also a 1/0 from there to the starter, I also have a 2 gauge wire going to the front of the car for a power tap and I think at least a 4 gauge going to my alternator.

 

[Evan11]

Your wires aren't nearly thick enough. The 4 gauge on the amp is doing no good if you just have 8 gauge to the alternator. I would run a zero or two gauge wire from the alternator to the battery, also the same size ground wire from the battery to the engine block, as well from the battery (-) to the body. I would then run a 2 gauge wire to the Amps with a distribution block, splitting it into two 4 gauges for the two Amps. I'd pick up a 140 amp alternator off of a 1994-ish Buick Roadmaster, you'd have 30 more amps of power right there. Also, I would run one really one battery, like a large "kinetic" & install a 3 or 4 Farrad capacitor back with the amps. I certainly think it would be much better to have the battery up front. the shorter the wire from the batt to the alt is, The more power you'll have. Hope this helps.

 

[tobyp]

I'll probably beef the supply wires. I am running a 20 farad hybrid digital cap

 

[Evan11]

Damn, a 20 Farrad cap is basically enough for 20,000 watts. You shouldn't need over 3-4 Farrad. 1-2 Farrad per 1,000 watts is the general rule.