Alternator Engine Load

[Brian617]

I have a 2008 Altima 2.5l with a 110 amp alt. When the base hits, the lights dim and the car sort of surges. Under acceleration or steady driving under power, such as up a slight grade, drum beats can be felt like braking action and the RPMs drop in sync with the beat. My first thought was the drop in voltage was affecting the engine. But after an email with Singer alternator, I'm thinking it may be the alternator loading to provide current and physically bogging down the engine.

Does anyone have experience with alternator loading?

Even if I add a second battery, the alternator will load on the drop to 12 volts, won't it?

Do high output alternators put noticeable drag on the engine?

Thanks,

Brian

[Broke_Audio_Addict]

I seriously doubt one stock alt would be enough to big you down like that. You could be having belt slip when is the last time you changed your belt and tensioner? Also what does your system consist of? it could be possible you are drawing so much power that you are pulling your voltage down to the point of almost shutting the car off and the alt is fighting to keep up Hence the surging and dimming

[Brian617]

Sorry it took so long to answer. I can only post early in the morning or late in the evening. I just have a couple of amps, an Orion XTR15001, and a Rockford Fosgate P8004. I think they both put out rated (1500 RMS and 800 RMS) given the proper input voltage. I changed the belt 20k miles ago. I'll look today for any belt dust or slippage indicators.

[Guest]

when did you change the tensioner

[jarrius]

On a stock 110amp alt you car running lets say 2.3k rms. i feel you are pulling more power then your car can supply and that could be causing the issue but i could be wrong.

Do you have a volt meter in your car if so what volts is it showing wile you are playing your system at 2k rpm's

[wccfan12]

I know exactly what you're talking about. My car has the equipment in my sig and when the bass hits I can kind of feel it bogging down the engine a little bit. Granted mine is a 4 banger and I"m assuming yours is the 2.5L v6, but I have a Mechman 240 amp alt and it does the same thing your stock alt is doing. On songs with a drum like beat it does the same thing as well, it's almost like I can feel it slowing down a tad with the beat. My friend's honda did the same thing when he installed some subs on a 1500 watt amp, he was running stock alt too. My car has done it for as long as I remember and I've never had an issue. With the equipment in sig and the Dc 3.5k at 0.4-.6 ohm voltage doesn't go below 13.0 so I know it ain't that.

[Brian617]

I know exactly what you're talking about. My car has the equipment in my sig and when the bass hits I can kind of feel it bogging down the engine a little bit. Granted mine is a 4 banger and I"m assuming yours is the 2.5L v6, but I have a Mechman 240 amp alt and it does the same thing your stock alt is doing. On songs with a drum like beat it does the same thing as well, it's almost like I can feel it slowing down a tad with the beat. My friend's honda did the same thing when he installed some subs on a 1500 watt amp, he was running stock alt too. My car has done it for as long as I remember and I've never had an issue. With the equipment in sig and the Dc 3.5k at 0.4-.6 ohm voltage doesn't go below 13.0 so I know it ain't that.

I appreciate your reply. You have pretty much confirmed my suspicions. And the 2.5l is the 4-cyl... the Nissan 6-cyl is a 3.5l. My lights are dimming too, so I have 2 problems; voltage drop and alternator loading. I think I'll add another battery and a capacitor before I go buying a 500 dollar alternator. I don't listen long at full volume, so I'd hope two batteries would find time to charge. I think a cap would stiffen short drops a bit.

I've read in several forums to get a good quality capacitor. There's several references to the ones in a felt lined box and a volt meter being bad, but no real references to which ones to actually get. I'd be looking at 1F caps... probably two in parallel. What caps might be good quality for the money?

[jarrius]

IMO. the amount of money you will be spending a second battery and a good cap should be just about the price of a alt.

Optima yellow top (ok for car audio) 150-200

Rockford Fosgate 1 farad cap (looks kinda cheap to me) 75-107 from sonic electronics

so on the cheap end you can get away with spending about 250.

Here is the better way to do things IMO with out adding a alt

xs power d3400 and xs power d680 OR the xp2000.

the xp2000 is about 250 and the d680 is about 125. and the d3400 is about another 250

really the choice is yours but IF it where me I would just get the alt and do the big 3.

[Tarball]

Over 2k RMS you need batteries and h.o. alt. To do it properly.

[MECHMAN]

Adding a high output alternator will worsen the "engine bogging" problem, but improve the voltage drop problem.

Assuming that your system will actually use more than the 110 amp capacity that you currently have, the car will slow down more when the bass hits. More amperage requires more Horsepower, there is no way around that.

We could tell you otherwise in order to try and sell you an alternator, but we would be lying.