Scope

iTrader: (5)

Should I completly install a powerful car audio system, probably about 1500 watts or more, from my car battery and alternator or just use a different car battery that is only hooked up top my amps only. If I do that shold I install the battery in my trunk and use a capacitator.? If not what do you think I should do when installing it from my car battery and alternator? Should use a capacitator? How do you insatll one anyway? Please feel free to post ideas too!!

djfrestyl

iTrader: (89)

whats a capacitator?

Scope

iTrader: (5)

I mean capacitor my fault

foetray

Always start with the source of the charging system- the alternator. Caps only supplement the charging system of the vehicle, so if the CS is weak(which most imports are)then the gain of a cap will be minimal. Check the specs of the amp and find out the amperage it uses for the impedence you plan to operate it at and boost the alternator accordingly. You may save money on caps and batteries this way.
If you should still need a cap, you should have 1 farad of capacitance for every 1000 watts.(1000=1 farad, 1500=1.5 farads etc.)

jmax

Alternator is last, not first, last. It's that way in the book for a reason - good electrical theory and knowledge.

Cap, battery, alt, it all depends on the exact system and how it will be used. If you are listening to music in parking lots with the engine off the battery will need to be upgraded or supplemented in some way. If you only listen to music with the engine on the factory battery or similar but slightly larger should last several years with a couple kwatts.

How many watts and what amplifier class? Any extra's such as lights, video game consoles, etc. All the average and max currents must be considered as well as the percentage of time that each item will draw near max current. With most music amps draw a very small percentage of max current.

foetray

Last, huh? Any amp pushing 1500 watts is going to draw at least 60 amps of current. Explain how a 90 amp alt is going to charge the factory battery, a second battery, and run a stereo. without a alt boost something is going to suffer- most likely the charge to the battery. The factory alt is designed to keep the battery at full charge during use of factory options on the car- not added car stereo. So when you add an amp with a 60 amp draw to a charging system of 90-95 it's not hard to see that the alternator is not big enough to handle it. The amp when the car running is pulling 60 so 30-35 is going to charge the battery as opposed to the original 90. Easy to see the difference at night when your lights are dimming when the bass hits. While you don't see the effect immediately, eventually the alt will give out from all the extra current on the system. Yes, an extra battery is recommended to run the stereo when the car is off, but if the alternator doesn't have enough juice to charge one battery, how's it gonna charge two? What is he going to do, ride around with the stereo off and play it when he parks? I say it because I've done it. I bought the caps and extra batteries and don't have either anymore. The only thing that really made a difference was the boosted alternator. I'm just trying to save him the money I wasted on things that didn't solve the problem.

jmax

Look at the vehicles that win competition with several thousand watts and only 180 - 300 amps of alt juice. Music does not draw max current for more than 5% - 20% of the time. The other 80% - 95% of the time the batteries are recharging.

Lets look here, 1500 watts class D draws about 130 amps at full RMS output. Or at most 20% of the time. The rest of the time while driving down the road we have more than enough current to drive and charge the battery as well as listen to music. During those very brief instants that we draw more current than the factory 105-120 amp Maxima alt is capable of delivering we draw from the battery. The battery is likely able to deliver 500 - 800 amps for several seconds or more. No problems.

I never said battery was first. Alternator is last to replace and most expensive. Aftermarket alt is also more expensive to maintain and draws more power from the engine. Try driving a civic or any 4 cylinder with a high amp alt if you don't believe.

In case you still don't know the first step is to ensure that the power and ground wiring are as short as possible and as large as they need to be. If they aren't sufficient you have resistance, heat, and voltage drop. Cut corners on the wiring and you'll pay further down the line.

By the way, my wife's 60 amp alt Jetta is fine with a 1300 watt stereo.

foetray

I have not only seen competition cars I know the owner of a couple personally(1. Me 2. Steve Cook-3x world champ) and while what you say about wiring is true, it means nothing if you don't have the juice to charge it. If you look in DB Drag extrem class you'll see alot of batteries and alt upgrades. Why? Because a battery is nothing without an alternator to charge it. I know the alternator is an expensive upgrade, but it's more expensive after trying things that don't help. It's just like building a race car- you wouldn't buy a turbo before building the engine would you? Same thing. Start at the source of power and eliminate the guesswork. Competition cars aren't built for everyday pounding on the street, but still have upgraded alternators that can give the juice they need. Everyday riders need the same just as much if not more because of the everyday wear and tear put on the system. If your building a race car with a stereo system it may be different due to lack of power from big alts, but in order to properly do one somoething must be sacrificed(speed or power).

jmax

I guess you missed the part where music is dynamic. And you missed in high school physics and math the importance of putting the equation together correctly. Getting a high output alt for a < 2000 watt daily driver in the maxima is like having a V8 on a motorcycle that only has a 50 lb rider and never exceeds 5 miles per hour. It is pointless. Read and educate yourself before you spend money on items that do nothing for your performance or sound. And don't tell others to go buy something they don't need, it's rude.
Below are some of the important tech briefs that should be read by anyone considering a high output car system. These should be read regardless of what you have been told in the past and may set some misbeliefs to rest.

http://www.autosound2000.com/detail....ODUCT_ID=A2414
http://www.autosound2000.com/detail....ODUCT_ID=A2452
http://www.autosound2000.com/detail....ODUCT_ID=A2535
http://www.autosound2000.com/detail....ODUCT_ID=A2483
http://www.autosound2000.com/detail....ODUCT_ID=A2540
http://www.autosound2000.com/detail....ODUCT_ID=A2443
http://www.autosound2000.com/detail....ODUCT_ID=A2597
http://www.autosound2000.com/detail....ODUCT_ID=A2433
http://www.autosound2000.com/detail....ODUCT_ID=A2473
http://www.autosound2000.com/detail....ODUCT_ID=A2434
http://www.autosound2000.com/detail....ODUCT_ID=A2449
http://www.autosound2000.com/detail....ODUCT_ID=A2437

foetray

I don't read about building car stereos- I build them. I don't fault you because I used to beleive the same thing 2 alternators ago. The fact remains your're killing the alternator with the extra load. Check the voltage of the charging system with the stereo at full blast and notice the drops in voltage. Pretty soon what was a 2 volt drop becomes 4, then 6, etc. Slowly killing cells in batteries because the alt doesn't have the juice to charge it and run the stereo. Straining the alternator trying to power a system it wasn't designed to support. I'm not saying hook it up today and it'll die tommorow, but it can cause problems along the way that could have been avoided by upgrading the charging system. I wouldn't be suggesting it if I hadn't already been through it. Yes music is dynamic, and on the deepest notes amps draw the most current taking power from where it needs including the charge to the battery. Unless you run a deep cycle battery, once discharged it never regains full charge so your constantly pulling from a battery that's not 100% and can't get there because of the extra load. That kills cells. Also, most amps are tested and rated at 13-14 volts which is impossible to keep without an alt. upgrade. So for maximum performance an upgrade is recommended. If your body stops pumping blood, check the heart. Losing voltage? Check the alt. Same thing.

jmax

I suggest you start reading. As most experts in the field of car audio will suggest installers know almost nothing about cars, audio, and musical reproduction. Therefore it is nearly impossible to learn in the field without messing up a whole lot of people's stuff. You screw up once, no big deal. Screw up twice and you're showing the flaws of your education.

Start with the wireing everytime. Without the proper wireing the power can not get to the amps and speakers.

By the way, I am speaking from both book knowledge and experience in car and home audio. Not to mention a little bit of experience in bands and working with sound reproduction in large rooms. Many woofers in car can reproduce 100 dB or more with 1 watt of amp power. From the math you can see that the same sub in the same enclosure if within it's linear power band would need 1024 watts to reach 130 dB's. Well above the point needed to cause permanent hearing loss. Now put that same sub in a ported box and you have 140 or more dB's. Of course this considers the environment to behave linearly as well. You may not win a large SPL event with a stock maxima alternator but you will easilly cause yourself to go deaf years before killing the battery or alternator.

Scope

iTrader: (5)

Thanks for the surprising arguements and I will take these arguments into consideration because this is my first car and I don't want to blow the alternator using these amps so I will most likely upgrade the alt from a rspectable company, not one whose alt dies two weeks later, and make sure nothing else is going wrong from this system. I am taking in a second guess for this system because I don't want all that bass in my car but I will probably have a 1000 - 1500watt system. Since I am a beginner with this I am not installing it. I have a friend that did it for another one of my friends car and it was off the hook. So thank you and I will consider it.

jmax

I don't mean to argue but many don't know what they believe they know. If the 1500 watts will be powering mostly mids and tweets you don't need a battery, alt or cap upgrade. Mids and tweets use very little of an amps available power. As in a tiny fraction. I would buy solar cells and super glue them to your roof sooner than I would get a new alt. Unless I stood to make a profit off of the alt, the new belt every 6 months, and other accesories to make it perform up to it's ability.

foetray

It wasn't an arguement for me, I was trying to understand his point of view. To argue would somewhat discredit him, and I don't intend to take away from what he has seen, learned or experienced. But I know car stereo and I know what I went through in both my Maximas. To get maximum performance out of an amp you need to be able to keep the voltage up, and the best way I found was a new alt. Did it 2 years ago with no probs. And I do agree with him about the importance of wiring. You don't want your amp to drink power through a straw so make sure power wire is appropriate size and ground wires are short as possible.

jmax

Spend $50 - $100 on a good high amperage AC/DC DMM. It's pretty funny to see how little current your system draws. I think the last time I checked mine with 1200-1400 watts of amp power, headlights on, AC on high, defrost on, etc. Stereo was cranked to a level that was uncomfortable for the ears. Current draw from the alt was either 70 or 90 amps. I can't remember. By the way, the alt wasn't a limiting factor as it is a 185 amp OG. And voltage didn't drop below 14.3-14.4 at the amps. I have one more link for you. I found this last night and couldn't post. It attempts to refute the use of caps but doesn't take all the necessary measurements to show anything. But it does effectively show the uselessness of high amp alts for car audio when music is the listening material.

http://www.welcometotheden.8k.com/caraudio/Captest.pdf

foetray

Okay, but try this. Tune the stereo for optimum sound then turn it up so that the amps are actually trying to operate at maximum power. Measure it then. I'm sure you'll see noticeable drops in voltage on low bass tones. It's not going to drop as much when the amp isn't working as hard. Also at times when voltage is low, the amp is not putting out the max amount of power that it's capable of, but the max amount it can put out at that voltage. If you never play your radio "on kill" then you may have no problems, but if your're setting up a big bass system to be played on kill everyday you'll need more voltage to do it. We found that in many applications caps and isolators restrict voltage more than help it, so we use Stinger solenoids for secondary battery applications. I had to get my car worked on and whatever it was required removal of the alt to fix, so I had to run my factory (rebuilt) alt so we took the time to measure the difference in amperage and voltage for ourselves. No caps or batteries the voltage dropped considerably more with the factory alt with stereo on kill.

jmax

As I said that was pretty much full tilt. Measureing amperage draw it never reached the stock alt limit. Never went above 78% of capacity. And that was with all the accessory stuff turned on. Very unrealistic for everyday purposes. If you are seing noticable voltage drop in a maxima with the big stock alt you most likely have wiring issues to take care of.

I had a small drop last year and traced it to a circuit breaker. Switching from a high amp circuit breaker to a fuse got me an extra 0.5 volt to the battery. It's amazing how one little thing can do so much harm.

foetray

I've got 1/0 awg power(2- 4awg inputs at amp),2- 4awg ground(18" each), 10 awg speakerwire to subs, 12 awg to mids and tweets. about 3000 watts total.
I expect a little voltage drop but the stock was dropping to 8 volts while my boosted alt only drops to 12 from 14.5.
What size/brand amps and subs are you running? Total power? that could be the difference.

97GLES

iTrader: (5)

if you need alot of power just get a generator. lol lolol

jmax

1/0 is only rated to about 150 amps current for the length of wire needed to get to the amps. I would be using three of those 1/0's with that amount of power. I measure about 370 amps current draw at 12.5 volts? Guestimating 2/3 of the power is class D? Remember, when you have voltage drop to compensate to get the same ouput power amperage increases. Class D example (2000 watts/ 0.8 (efficiency) ) / 14.4 volts = 174 amps. (2000 watts / 0.8 (efficiency)) / 12.5 volts = 200 amps. (2000 watts / 0.8 (efficiency)) / 11 volts = 227 amps. In this example restriction in the cable resulting in 3.4 volts less at the amp needed an additional 56 amps of current to attain the same level of power.

If you are a competitor the rule books normally have standard minimums for power wire gauge. Also large point deductions for using too small of wire.

3000 watts is a far stretch from 2000 watts. For that level of power I would recommend a high output alt for the maxima. In the system I tested I had a 4X50 watt RMS alpine powering rear mids and front tweets. A PG ZXTi series 4 channel, 125 X 4 at 2 ohms per channel powering front mids and midbass, and a MTX 1000D powering the sub, 4 ohms 680 watts X 1.

The system that is being put in my car now will have about 3700 - 4200 watts RMS without center channel. With center channel the output will jump another 300 watts RMS. 2700 - 3200 watts will be class D, 1000 - 1300 watts class AB. One 4/0 cable is large enough to deliver all the current I will need for music. But to be on the safe side and for burps I will likely use two 4/0 cables or have a seperate 1/0 for the mid / tweet amps. I will be using an ICB for the main power wire and possibly for the sub and midbass amps if Intra makes one the needed size, 150 amps.

As I said before I already have an OG 185 amp alt. I may upgrade it to something larger or I may have a dual alt set-up. Finding time to drive to Pittsburg for the custom dual alt set-up is what's keeping me from having that already. I am also looking into solutions to reduce the 3-phase noise of the large alts.

foetray

I got a big alt from Ohio Generators-250 amp. The actual problem of drop originated when I was running a 1500 watt setup. Then I was using A/B amps too. I just in the last year upgraded to the 3000 watt setup. I figured I'd have to run another big power wire,but I'm going up another 2000 watts for competition this season so I'm waiting to do it then. The amp I have was somewhat experimental in my car,so I didn't do the proper changes at the time. I liked the amp though , so I'm getting another. That sounds like I should be having problems now but like I said I expected drop. Before I changed amps there was very little.What about when I had the 1500 watts before? Sounds to me like your're building a real monster. Let me know how it turns out.

foetray

that really is funny because I actually do have one. How did you know? lol

jmax

The diesel fumes are a bit much in the car. But it definitely helps in the spl comps. LOL

Unless Tom and Gus at OG have changed something since we last spoke on the phone anything larger than their 185 amp alt is not for daily drivers. Not highly reliable or useful for day to day use. Did you measure your drop at idle or with the engine revving? One thing the big alt does to generate power is that it needs to rev higher than the stock alt. Unless you boost your idle speed it won't have much power at idle.

Send me an email, this forum keeps going down. j_grieve33@hotmail.com