The infamous capacitor discussion

[LongThrow]

I've done much research on this (as far as google goes) and I have never so many mixed reviews on the necessity of this in my life.

I'll start with my problem.

all my equipment is in my sig, but for the lazy scrollers, 94 ford explorer - normal battery from autozone - brand new 95 amp (same rating as the stock alternator) alternator which is specfically for this vehicle. 4 guage KnuConceptz wiring. 500w sub amp wired to 2 ohm. Tested battery at autozone, it's fine. Alternator is fine. Wiring and connections are secure. Fuses are fused properly. Ground is clear of paint and is perfect. Tested battery again with DMM, showing 12.89 at idle with car off. Car running at idle shows 14.34. However, every now and then, when my car is at a stop light, I'll have 2-4v voltage drops. I'll turn my stereo off, still having dips in the voltage. This is only when stopped, while driving is fine.

was told a capacitor would fix my problem, no more than a 1.0 would be needed. is 500w + the 150w of my door speaker amp = 650w of power be too much on my stock system? Have not done big 3 uprade was told it was unnecessary for the entry-level equipment I have.

I'm wearing a fireman suit so I don't get burned by the flames I'm about to encounter.

Click to read more...

 

[big scott]

that is not going to help with a voltage drop like that.

you have something wrong or your trucks ecm is controlling your alt.

and the caps you see at like sonic are really no good.

now the maxxwell cap are good but expensive.

 

[wew lad 5,000+ posts]

it sounds like a problem with your vehicle considering you still get the drop when you turn the stereo off. the most drop i'd imagine you'll get with that system maxed out would be no more than one volt.

i'd look into the alternator voltage regulator, and possibly the PCM if your year ford has one, im really not familiar with fords. newer vehicles will turn off the alternator at idle to save gas mileage - i doubt a 94 would have that.

 

[brafferty]

newer vehicles will turn off the alternator at idle to save gas mileage - i doubt a 94 would have that.

is this why ive died at a stop light once or twice?

 

[wew lad 5,000+ posts]

is this why ive died at a stop light once or twice?

need more information than that, but an alternator turned off will not cause a car to die imo

 

[adulbrich 5,000+ posts]

I'm getting some of these after high school when I move my system to the Silverado

XS Power XS15K Lithium Powercell (XS15K)

Quick power like caps, and lots of reserve

 

[LongThrow]

that is not going to help with a voltage drop like that.
you have something wrong or your trucks ecm is controlling your alt.

and the caps you see at like sonic are really no good.

now the maxxwell cap are good but expensive.

How would i go about testing this? Take it into a mechanic/audio shop?

I forgot to mention, my lights also have a constant flutter/flicker when my car is on. Just the headlights, not the rear lights, brake lights, headlamp interior lights, etc. If it means anything, my relay box under the hood GETS HOT, I guess that is normal considering how hot and humid it gets in the Missouri summer.

it sounds like a problem with your vehicle considering you still get the drop when you turn the stereo off. the most drop i'd imagine you'll get with that system maxed out would be no more than one volt.
i'd look into the alternator voltage regulator, and possibly the PCM if your year ford has one, im really not familiar with fords. newer vehicles will turn off the alternator at idle to save gas mileage - i doubt a 94 would have that.

I'll check that out.

Thanks for the speedy replies!

 

[LongThrow]

need more information than that, but an alternator turned off will not cause a car to die imo

Forgive me for the noob question - but I replaced my alternator last week sometime, and had it tested before I even installed it. Is a voltage regulator apart of the alternator? Or does it "clip on" after assembly? Because if i replaced my alternator, then it shouldnt be the regulator - if it is apart of the alternator as a whole.

 

[trumpet 5,000+ posts]

You need to get the vehicle checked by a reputable auto tech. At minimum, take it to a parts store that does free charging system tests. An Interstate Batteries store will do this as well.

 

[LongThrow]

that is not going to help with a voltage drop like that.
you have something wrong or your trucks ecm is controlling your alt.

and the caps you see at like sonic are really no good.

now the maxxwell cap are good but expensive.

I was told my alternator is only rated for my vehicles specified power, and maybe 10-15 amps on top of the normal operating power of the vehicle. And that my audio system was pulling too much power - over the rated amps of the alternator. But what does he know? Autozone employee.

 

[wew lad 5,000+ posts]

Forgive me for the noob question - but I replaced my alternator last week sometime, and had it tested before I even installed it. Is a voltage regulator apart of the alternator? Or does it "clip on" after assembly? Because if i replaced my alternator, then it shouldnt be the regulator - if it is apart of the alternator as a whole.

it's an internal part of most stock alternators, it's unlikely that it failed new but its possible and should be checked. the other option would be the computer commanding the alternator to a lower voltage.

 

[LongThrow]

You need to get the vehicle checked by a reputable auto tech. At minimum, take it to a parts store that does free charging system tests. An Interstate Batteries store will do this as well.

Any 'reputable' mechanic shop? Or specifically one that works on electronics? I took it to auto zone and had them test the battery and alternator, but is there a seperate whole-circuit charging that can test more than just the single battle or single alternator? Would it cost anything to have a auto shop just look at it/test it?

it's an internal part of most stock alternators, it's unlikely that it failed new but its possible and should be checked. the other option would be the computer commanding the alternator to a lower voltage.

So back to the shop it is.

 

[wew lad 5,000+ posts]

I would try to find a local alternator specific shop with good reviews and recommendations. They'll have the real deal as far as equipment to check your charging system. Auto parts stores will have a tool as well but I've had good batteries test bad on those so I tend to lean away from them.

 

[trumpet 5,000+ posts]

Any 'reputable' mechanic shop? Or specifically one that works on electronics? I took it to auto zone and had them test the battery and alternator, but is there a seperate whole-circuit charging that can test more than just the single battle or single alternator? Would it cost anything to have a auto shop just look at it/test it?

Your Explorer's charging system is simple. A computerized charging system tester should make quick work of this, although there's a slight chance a tech may need to take the vehicle for a drive to confirm the problem. Nobody can tell you if an auto shop will charge you for testing it, but I doubt this has anything to do with your sound system's current draw. Expect them to find a problem that will cost you money.

 

[UMWDawg92 10+ year member]

Have you done the big 3? On these old fords, you can upgrade your alt quite cheaply just fyi, do you have the 3g alt? If you do they made the 3g in a stock 130amp version and there are tons of reasonably priced aftermarket 3g that are rewound to produce 150-200amps. The 3g is internally regulated and the regulator is mounted on the alt, you can try replacing it. They only cost about $15 for just the regulator.