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Hey all, I am a member of caraudioforum.com which I am sure alot of you are members of as well. I was talking to some people about a problem I was having with, A) dimming headlights and B) Voltage on my Alpine M301 jumping around from 10V-14.4V. They all told me to start out by grounding the battery with larger wire, atleast as big as your power wire, to the chasis. Previously, I did the grounding kit DIY, but I only used 8G wire and bolted it to I think it was 5 places in my engine bay. I didn't notice a difference with the headlights, and it obviously doesn't do a thing with stabalizing the voltage on my amplifier. Probably the same way with my Alpine T420, except I can't tell because there is no digital readout. But anyways, for those of you that have a system and have upgraded the ground correctly, I didn't do it correctly, does it really make that much of a difference. Do you all think that will keep my amplifier voltage stable? I can assure you that the amplifiers are grounded correctly in the first place. Or should I go ahead and to the "Big 3", battery - to chasis, alternator to battery +, Chasis to engine? Thanks.

 
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ifa nything I would say get a bigger battery, all the wires in the world will do you no good unless you are supplying more power to go thru them

 
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I have a new battery, it isn't a yellowtop or something, its a diehard I believe. The old stock battery was a piece of ****, my system kept on draining it and eventually killed it.

 
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I upgraded my grounds today and it fixed the problem. I connected the chasis to battery and the engine to the negative via 4G wire. Basically through the same two points in which the stock ground is connected, but with their own seperate wire going to the ground. Now my amplifier Voltage stays pretty constant, in the high 13V range - 14.4V. Can't wait until tonite when I test it out to see if my headlights dim with the bass hitting.

 
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Grounding is gonna help but its still not gonna fix your problem 100%. The electrical system in your car was designed for the stcok components. When you add a sound system (especially a big sound system) it starts to taking over and takes the power from other components. So the only real solution is to add more power, a new battery is still not the answer, at the end your power supply will have to be upgraded (alternator).

 
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^^ Did you get a new alternator?

 
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Yea, I am not going to spend all that money for a new alternator. I will live with the flashing headlights, etc for the time. Also, I thought that the grounding fixed the problem with the amplifier voltage jumping around, and when my car is idling, it stays pretty constant but when I start driving around, the voltage starts to jump around more. I don't know if it is grounding or just my amplifier not getting enough power because of the other amplifier I have running my components or what. This is one thing that I don't understand about my amplifier:

RMS Power (at 12V,20Hz-200Hz)

Per Channel into 2Ohms (Š1% THD+N) : 250W x 1
Per Channel into 4Ohms (Š1% THD+N) : 150W x 1

RMS Power (at 14.4V,20Hz-200Hz)

Per Channel into 2Ohms (Š1% THD+N) : 350W x 1
Per Channel into 4Ohms (Š1% THD+N) : 175W x 1

At 2Ohms, which my 12w6v2 is wired at, the power can be 350W or 250W, depending on the voltage going to the amplifier. What dictates whether the voltage is at 12V or 14.4V?

 
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Most cars votage are affected by the rpm of the engine.

 
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That makes sense, but why would the voltage go down when I am driving and the RPMs are higher vs going up when my engine RPM is lower at idle?

 
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Its probably a honda thing to try to save gas. I notice on my car it does freaky things with voltage. They probably compute the level of the battery and adjust the alternator to only give as much power as needed to keep a voltage. My voltage usualy sits around 13.5 to 13.8V. When I turn up my radio I can drop it do 11.5 though

 
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would a yellow top battery fix the problem?

 
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interesting. I have an Alpine MRD-M501 and the headlights dim alot. At idle the voltage seems to drop as low as 10 volts when the bass really kicks in. I have not checked the voltage while driving though the lights seem to dim less than at idle. This amp really does seem to draw alot of current.

 
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Actually, if your car is running your alternator is normally supplying somwehere around 14v (13.8-14.4). When the amp is running off the battery, it will only be supplied with 12v. Therefore, what dictates whether you get 12v or 14.4v is whether or not your car is running.

 
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2k2civic, have you checked this out for yourself on your civic? Mine never goes up above 14.0 and only occasionaly even hits 14.0V.

 
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i can get about 14.2 or even 14.3 on a good day when I first start my car

I have a huge amp though (1400w) and I have never seen my voltage drop to 10v... damn

 
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I drive a hybrid so my voltage is probably more regulated since they use the motor assist as the alternator. And you can't have both at the same time. Either that or I have a bad cell in my brand new battery. And that would make me mad

 
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The ideal running voltage on a new car is 14.4 Volts. Resting Voltage is around 12V. The charging system(alternator) determines the increase in voltage. I imagin there are alternators that would produce more current and therefor be able to sustain the higher voltage better...

 
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I actually haven't tested my car but I would imagine if would be on the lower end maybe 13.8-14v while running. It is correct that the alternator would determine the voltage and the reason you would hit 14.3 when first starting your car is because when the car first starts and is cold it be in a high idle which would produce slightly more power (alternator spins faster).

But ya, as far as I know, ideal running voltage is 14.4v. So I would imagine thats why most manufacturers rate their amps with 14.4v. I've seen a few manufacturers that rate amps at 13.8 instead of 14.4, but not many do.

 
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Just curious, what brand/model amp is this?

 
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Yea, I guess its just our electrical systems, they are just restrictive and a new alternator would probably be the only solution. I drove back to college today and on the highway with the RPMs higher, my amplifier stayed in the high 13V range. Overall, my subwoofer still hits hard regardless of where the voltage is and the temperature of my amplifier stays pretty low since it has good ventilation. As for my Alpine M420, I can't tell the voltage since there is no digital readout, but I am sure it is the same way. Do I really have to worry about either my M301 or M420 failing on me because of the voltage issue, keeping in mind that both stay pretty cool and don't overheat? Thanks.

 
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Wow, when I start my car, it's usually around 14.4-14.7 V.. then after I drive around, it'll drop down and stay around 14.4..

Before I upgraded my alternator, I would drive around and I have the stereo on (I have two M300s), it would drop down as low as 12.1 volts.. I upgraded to a 200 amp alternator, an optima yellow top, and 0/1 awg wiring for my power and grounds.. now it usually doesn't drop below 13.5 V when I'm idling.

ZSKCivic01 ,no, you shouldn't have to worry about the M300 and M420 failing on you. If you say it's staying pretty cool, it'll be fine... Staying in the high 13s is pretty good and you shouldn't have anything to worry about.