Proper Power

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VW337
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Proper Power

Post by VW337 »

Most automobile electrical systems from the factory are adequate for what the vehicle is factory equipped with. The minute you start adding audio equipment, alarms, video, and countless other powered accessories you are exceeding the factory limits. A weak electrical system can cause noise in your audio and video, you may also notice your headlights dimming to the music. The following information is provided at an informational level as guideline for proper planning of your installation.

Step 1 Under Hood Cabling

Replace the factory cable connecting 12+ on the battery to the alternator, in many cases the factory cable is 8 gauge and will restrict the current flow in high demand applications. Add a cable between the battery ground (12-) and the mounting bolt of the alternator, the factory does not use a cable to do this and relies on typically very weak ground connections between the alternator and battery. Upgrade the factory ground (12-) to chassis connection at the battery as well. Use at least 4 gauge cables for all of the preceding upgrades.

Step 2 Battery/Batteries

The vehicle manufacturer will usually provide an “adequate” battery but you will typically want to replace this as well. Look at your existing battery for a value indicated as CCA in many cases it will be near 500; this value is your Cold Cranking Amps. This is the current surge capability of a given battery at 32F for 30 seconds or before falling below 7.2 volts. The other value you will want to be aware of is the RC or Reserve Capacity. The RC is the most important factor when talking car audio. The RC rating is the time needed to lower battery terminal voltage below 10.2 V at a discharge rate of 25 amps. This is with the battery fully charged and at 80° F. Reserve capacity will appear on the battery as a time interval in minutes. When you are looking for a replacement battery there are many options. You will want to look at options that will actually fit in your factory location (unless you plan on relocating it) with a CCA value of 750 or greater and an RC of 80 or greater. Only one battery is needed in most cases since the audio system actually runs off of the alternator while the vehicle is running, but if you are listening to your music for extended periods of time with the vehicle off you will want a second battery. The second battery will need to be separated from the primary battery so that you will be able to start the car even if your audio has completely drained the secondary battery. To do this we suggest using a solenoid, an isolator will work as well but has a slight internal voltage loss.

Step 3 Capacitor

Capacitors are very misunderstood, since they are typically sold for the wrong reason. A capacitor will not stop your headlights from dimming. A capacitor will store power which it can discharge faster than your battery for dynamic musical peaks; this does not mean that if the bass goes boom every other note that it will help. If you are listening to your music loud or have excessive peaks in your listening the capacitor will continue functioning but in a semi-charged state since it is constantly being drained and not given a chance to fully recharge between notes. A capacitor will help stabilize the voltage that the amplifier is seeing when the music is dynamic, and in this case it will aid in keeping the headlights from dimming. The most overlooked purpose of an external capacitor is to help filter any excess AC voltage ripple that has made it beyond the voltage regulator within the alternator and also beyond the battery. This filtering allows the amplifier to deal with as close to pure DC voltage as it can so it will run cleaner and more effectively. The audio signal within an amplifier is AC voltage and if the amp is seeing AC from your electrical system it can color the music that you will eventually hear, typically heard as alternator whine.

Step 4 Alternator

Not all audio upgrades require an alternator upgrade. To save you the effort of reading: if your total suggested fusing of all of the amplifiers combined in your audio system does not exceed 60 amps then there is very little need to upgrade your alternator unless it is already failing. To decide if you need to upgrade your alternator, first you will need to know what the amperage ability of your factory unit is. You will likely need to check with the manufacturer to get the specifics on your alternator but in many cases it will be stamped on a plate somewhere on the units housing, or you can do some rough figuring see below:

• 4 cylinder no frills 50 amp
• 4 cylinder w/AC 60amp
• 4 cylinder w/power windows 60amp
• 4 cylinder loaded 65amp
• 6 cylinder add 5-10 amps to previous values
• 8 cylinder add 10-15 amps to previous values
• Trucks with tow package or large SUV will have values between 90-120 amps

Next you will need to know what the amperage draw of your audio system is. You can easily sum this up by combining the total fuse ratings for each unit, this will give you a very rough idea of the systems current draw; if the total fuse value of all of your installed audio components is 200% or greater than the value of your installed alternator then the alternator will need to go. If you are exceeding the value of your alternator with your total fuse value but not in excess of that 200% mark as mentioned you will need to now think of your listening habits. In regard to your listening habits, if you have ever been glared at sitting at an intersection, or are constantly readjusting your rear view mirror then it is likely that you listen to your music loud. If you listen to your music at high levels for extended period it is very likely that you are running your amplifiers to just below the fuse ratings (peaks will exceed the ratings without blowing the fuse). If you listen at higher levels and you are exceeding the amperage rating of you alternator by any amount directly compared to your total fuse ratings then you will truly want to upgrade your alternator. On the other hand if your typical listening level (95% of the time) can be easily spoken over, you just have too much potential power and you should not need to upgrade your alternator unless you really want to.
I think we've established that "Ka Ka" and "Tukki Tukki" don't work.
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Drock
Posts: 1846
Joined: Wed May 23, 2012 4:44 pm
Location: Canada

Re: Proper Power

Post by Drock »

Good info here. But I need a bit more info. My question is about the battery reserve. I'm trying to figure out how many batteries I need.
I want to run an elite.1 and two elite.4's. So my fused total is 500amps. I currently have two alts, one at 130amps and the second at 250amps. I also have two optima yellow tops. They have cca at 750. And R/C of 120min. How do I know/calculate how many batteries I need to keep up.
I know my setup works fine at normal levels the way it is.
But just for shits and giggles what if I wanted to add my second elite.1. Or alternatively pull out the elite.1 and give "the one" amp a whirl. What should I do?
I was told I should have matching alts. So I ordered another 250amp alt.
If anyone can help with a nice drawing it would be great. Or lead me to an existing drawing.
Thanks
D


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Kirghiz
Posts: 1013
Joined: Wed Dec 26, 2012 7:59 pm

Re: Proper Power

Post by Kirghiz »

I have this one battery and a 300 amp alternator dedicated to an Elite.1 at 1 ohm and an Elite.4 at 4/2 ohm split load. My voltage pretty much stays rock solid at 14.6-14.8 except for the very odd drop down to 14.4v. That is true at idle as well, and jamming wide open. I probably have overkill on mine, but I wanted stability, and to not worry about voltage. I have the power to add a second Elite.4 easily, but I would double that up (2 300 amp alts and 2 of those batteries) if I added a second Elite.1 and another Elite A/B full range. That's where my thought process is at on mine anyway.

http://www.stingerelectronics.com/produ ... ductId=611

Just guessing, but I'd say if you ran the Elite.1 and 1 Elite.4 off of the big alt, and the second Elite.4 off the little alt you should be fine, but I'd say you wouldn't have much headroom for anything else since you're running your four channels all at full 2 ohm loads. That's just opinion based on how mine draws.

The One will pull about as much current as two Elite.1's strapped AND 2 Elite.4's at 2 ohms by itself. I wouldn't consider running that at all in a daily without 2 300 amp alts dedicated to it, and a 3rd alt to run the Elite.4s.
Being loud without good sound quality is pointless, but having good sound quality without being loud is also pointless.
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Drock
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Joined: Wed May 23, 2012 4:44 pm
Location: Canada

Re: Proper Power

Post by Drock »

Ya I was looking at those exact batteries. I put a call into Gentek for Eddie Bozo about a month ago to get a pair. But still no reply. I know someone that is running the one amp off a pair of these batts and it seems to work well.
The biggest alt I could get here was 250amp, so I have 500 amps available. But I'm still trying to figure out how many batts I need. If Eddie does return my call them I'll get those stingers.


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captainobvious
Posts: 58
Joined: Thu Dec 26, 2013 5:46 am

Re: Proper Power

Post by captainobvious »

I think people also need to look into the type of power supply their amp uses. Stiffening capacitors are essentially useless, especially when using an amplifier with a regulated power supply.
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