Acrimonus

Hey guys, I just got a new system in, I have one of those Alpine power packs that you can put behind the deck, I don't remember what it is called, 45W 4 channel, and a X1200M kenwood amp with two Alpine Type-R 10" subs. My car is a 2008 Hyundai Accent, I think I might be overloading my alt, when I crank it pretty loud using Ghosts n stuff by Deadmau5 as my test song the heaviest bass hits cause my lights to dim to the beat.

How much juice is going out here? I would assume that the kenwood amp is putting out 800W RMS not 1200 since it's only 1200W at 2 ohms and 800 at 4 ohms (not that I know what any of this means). It was professionally installed. If my headlights are dimming this is bad for my alternator right? I would need a more powerful one wouldn't I? Would installing an aftermarket alt void my warranty?

Also, to prevent any damage, turning my system down so that I'm not pumping it hard would prevent my alt from overloading correct?

JohnVroom

when your lights dimm the electrical SYSTEM is over loaded, not just the alternator but the battery and voltage regulation system. With the car running the power comes from the alternator (14 volts or so), if you draw more power than the alternator can provide at a given RPM then the voltage will dip (the voltage regulator will oppose this) then you will dip into the battery somewhere around 12.5 volts.

no juice just electricity...
you have a much better grip on electricity than most new guys. Assuming 800 watt draw you would be pulling 67 amps at 12 volts


it is putting a significant load on your alternator and it MIGHT shorten its life or not. As for voiding warranties that is a question for the holder of your warranty. An aftermarket alternator isn't a horrible idea as your cars charging system is probably 70 amps or less. Prior to that I would recommend a larger battery, an overdrive pulley on your alternator, and the big 3. (we have a sticky on the big 3 in this forum). Several (maybe 5) have sworn by using capacitors in this situation others swear at them

Also, to prevent any damage, turning my system down so that I'm not pumping it hard would prevent my alt from overloading correct? [/QUOTE] YES SIR

JohnVroom

The bottom line here is you have spent $ to get into this situation and the fix shouldnt cost more... big alternators are expensive, expensive to install, expensive to uninstall, expensive to ship back to the manufacturer and then to reinstall (lets assume it works the second time)

Acrimonus

I don't know if I want to use an overdrive pulley, that sounds like it would put some extra strain on the alternator. The dimming is pretty hard to notice, sometimes I feel like I'm just imagining it, but I'd rather not risk it.

How does replacing the battery help and the big three? Assuming the voltage that comes out of the alt is the same that goes into the battery, (12.6V?) then my alt can put out about 882 watts of energy at maximum assuming it is a 70 amp alt. My subwoofers by themselves are almost this much (800W RMS). Then you throw in AC, headlights, power steering, brakes, and the inner speakers (45x4 = 180W RMS). How would the alternator possibly keep up with this by replacing the battery? Is this assuming that everything isn't drawing at maximum all the time? (Like the subwoofers obviously are not playing 800 watts worth of power continuously).

MR2NR

iTrader: (66)

Start with the Big 3 (or 4) to make the delivery of current as efficient as possible. The larger capacity battery is just that, more capacity to help you through the peaks and store in the dips. A current draw is a slow downward spiral on batteries and alternators in most cases. Remember that it is not just the audio system that is drawing current, it is the rest of the vehicle as well. In winter throwing your heater and rear defrost on is going to draw lots of current as well.

JohnVroom

risk ... with an over drive pulley?? the overdrive pulley simply makes the alternator turn a little faster this allows the alternator to make more current at idle or at low RPM. It will not make more current than it was designed to, it will just make max current at say 2000 rpm. This is the same trick the aftermarket alternator folk use by the way. I would not give it a second thought unless you are winding out the engine to the rev limiter all the time. The challenge is finding the right pulley for your car

once the alternator runs out of power where will the power come from??? using a second battery is common using a bigger battery is common (this is like racing, if you don't have enough horse power or torque expect to be slow)

big 3 allows ALL the power in the system to flow to where it is needed, currently you have a car designed for a 30 watt stereo... you have to have an electrical system designed for the power used the big 3 is part of that. The 8 gauge wire feeding the cars ground ain't gonna cut it

the alternator wont keep up, the system will for brief periods (bass hits) exceed the car electrical system capacity and pull from the battery and if it pulls deep enough your lights dim. BTW you are changing your topic, your topic is "how do I stop my lights from dimming" not "how do I properly design my electrical system so that it properly feeds all the electrical needs of my car with an upgraded stereo". You will still briefly exceed your alternators power production but the larger faster acting AGM battery should eliminate the dimming... BTW without an overdrive pulley a 300 amp alternator will only make 50 amps at idle and you would still be on square one

sudanberry

This amp draws a lot of power (but puts out alot). A good battery, and alternator is key.