Help me please!!!! - Page 4

empathydude · 08-09-2004, 10:49 AM

Quote:

Originally Posted by sr20de4evr

The battery ground is upgraded to keep the voltage from dropping as the current leaves the battery, it really has nothing to do with the alternator or how it's designed/made at all.

How much it helps does vary from car to car, but the differences are based on how efficient the car's wiring is from the factory, not on how the alt is made.

upgrading the alternator does affect the performance. the battery will only supply so much power under a peak load, thats where caps come in. alternators supply an excess power all the time, so upgrading the wiring will allow more of that power to reach your amp before anything else.

sr20de4evr · 08-09-2004, 08:00 PM

I didn't follow any of that

What I was saying is that the only current that passes through the battery ground is current that's entering or leaving the battery, meaning the battery is either being charged or discharged. Whether the alt puts out full power at idle or not doesn't really have much to do with anything, upgrading the battery ground will still reduce a voltage drop whenever current is pulled from the battery. The upper limit on the amount of current that a battery can discharge is so high that it's ridiculous, I don't really know what that "the battery will only supply so much power under a peak load, thats where caps come in" came from, a battery can spit out however much current it needs to, several hundred amps if need be. You'll never draw so much current from the batt that you'll reach its upper limit.

Abell255 · 08-11-2004, 04:45 PM

oh, ok thanks

I got another 1 farad anyhow. Dirt cheap rockford. Also i upgraded the battery ground with 4awg. Coudlnt find the engine ground. thanks for all of your help.

Navy I.C. · 08-11-2004, 11:49 PM

good move...

empathydude · 08-12-2004, 04:29 AM

Quote:

Originally Posted by sr20de4evr

I didn't follow any of that

What I was saying is that the only current that passes through the battery ground is current that's entering or leaving the battery, meaning the battery is either being charged or discharged. Whether the alt puts out full power at idle or not doesn't really have much to do with anything, upgrading the battery ground will still reduce a voltage drop whenever current is pulled from the battery. The upper limit on the amount of current that a battery can discharge is so high that it's ridiculous, I don't really know what that "the battery will only supply so much power under a peak load, thats where caps come in" came from, a battery can spit out however much current it needs to, several hundred amps if need be. You'll never draw so much current from the batt that you'll reach its upper limit.

your logic fails at every corner...

1.The current hte alternator puts out at full power will DEFINITELY affect the voltage drop. upgrading hte engine/ battery grounding will give you a larger path for current flow, but with the alternator at full power you have an instant burst of 70 amps waiting already, thats why when you rev your car up and hold it there your lights don't dim as much on bass notes.

2. The batteries surge capacity is severely limited by the time it takes to create such a current (eg. the chemical reaction in the battery that creates the proton / electron chain) Yes a battery could create a PEAK (meaning momentarily) of more than 800 amps, the time it would take to do so would be far too long for any audio aplication without the use of charge capacitors.

3. A standard battery could possibly put out more than 500amps on peak, the the RESPONSE time of the current leaving the battery and reaching the amp is very long. THIS IS WHAT CAPS ARE FOR - They can create the current and transfer it to the amplifier and a much faster rate than a battery. What that means is, when you have just a battery, the current being created takes time to reach the amp, by the time the peak surge is supplied to the amp, the bass note has already passed or entered its reverse phase, which ends up causing clipping(unequal phase). A stiffening cap provides faster power to the amp to supliment the time between when the battery supplies its own peak current - allowing the amplifier to create a longer, and more even stroke to the subwoofer.

If you hooked several hundred amps up to one battery it would explode =(

sr20de4evr · 08-12-2004, 06:59 AM

1.The current hte alternator puts out at full power will DEFINITELY affect the voltage drop. upgrading hte engine/ battery grounding will give you a larger path for current flow, but with the alternator at full power you have an instant burst of 70 amps waiting already, thats why when you rev your car up and hold it there your lights don't dim as much on bass notes.
I never said the current that the alt put out didn't matter, I said that the rpm that the alt put its full power at didn't matter when it comes to what we're talking about

2. The batteries surge capacity is severely limited by the time it takes to create such a current (eg. the chemical reaction in the battery that creates the proton / electron chain) Yes a battery could create a PEAK (meaning momentarily) of more than 800 amps, the time it would take to do so would be far too long for any audio aplication without the use of charge capacitors.

3. A standard battery could possibly put out more than 500amps on peak, the the RESPONSE time of the current leaving the battery and reaching the amp is very long. THIS IS WHAT CAPS ARE FOR - They can create the current and transfer it to the amplifier and a much faster rate than a battery. What that means is, when you have just a battery, the current being created takes time to reach the amp, by the time the peak surge is supplied to the amp, the bass note has already passed or entered its reverse phase, which ends up causing clipping(unequal phase). A stiffening cap provides faster power to the amp to supliment the time between when the battery supplies its own peak current - allowing the amplifier to create a longer, and more even stroke to the subwoofer.
Yes it takes longer for a batt to spit out a bunch of current than a cap, but the difference is very small, not NEARLY as large as you keep implying. If it was indeed so big, then every sound quality car on the earth would have caps filling the entire car, yet you rarely even find ONE cap in a sound quality car. Why is that? Because these people have delved into car audio long enough and seriously enough to realize that caps have no real world use, it's all a marketing hype that the retail stores want you to believe so they can make more money off of the gullible and ignorant. There have even been tests done showing that caps made very little difference in the actual voltage the amp was receiving. For the price of a cap, there are so so so many things out there that will affect your sound more, hell just about anything you can do will be more useful.

PaulD · 08-17-2004, 06:31 PM

most "sound" cars are really SPL systems ... and caps will NOT help max bass. Bass is loudest when the dynamic range of the signal is very small and it is heavily clipped ....... caps work better with signal that have a high dynamic range (real music). What makes caps effective at all is that amps don't pull staright DC, they pull pulsed DC at like 60KHz - far too high of a frequency for the battery to supply, but easily possible for a cap with low ESR. As for power draw, remember that the battery is a LOAD (not a supply) until the voltage sags to the battery's float voltage.

Be careful of "upgrade" alternators, some of them put out less amps at idle than the stock one.

Abell255 · 08-17-2004, 08:05 PM

k.. i upgraded the engine/batt ground. Dim isnt as bad i dont think. But still, if i have the bass bumpin at idle, my rpm's go from 700 ( idle ) down to 350 then almost dies, then up to 900. I think i'm going to increase the idle to 1000 rpm's.

sr20de4evr · 08-22-2004, 09:50 PM

What makes caps effective at all is that amps don't pull staright DC, they pull pulsed DC at like 60KHz
stupid switching power supply, I always forget about that

remember that the battery is a LOAD (not a supply) until the voltage sags to the battery's float voltage
well, if the battery stayed at a constant 12.5V and could not be charged any higher (if the world was perfect and everything that was theoretical actually applied in the real world) then that would be an issue, but batts can build up a skin charge at 14V+ that can last for some time, so if the amp isn't drawing all that much current over what the alt can produce then it can draw from the battery without the system voltage dropping below 14V. I can turn off my car with the system playing and it will take several minutes before the voltage even drops below 13.0V, at least 3-4 minutes before it drops down to 12.5 with the system at a reasonable volume. With it cranked it will drop down to 12.5 within 10-20 seconds or so though.

as for the rpm dropping, the only real explanation I can come up with is when you put such a high draw on the alt, it loads down the engine considerably, and if you have a small engine it can drop down the rpm a bit before the idle controller can react and raise the idle back up. Not sure what to do to fix that though, other than raising the idle. If you do this though make sure you read the haynes manual and figure out how to do it the right way, don't just tighten up the throttle cable until the idle rpm goes up to 1000.

Abell255 · 08-22-2004, 11:40 PM

damn, the genious has spoken. yea, i somewhat understand what your saying... yea i've got the manual, and im going to raise the idle to 900 tomorro. All u do is turn a bolt with a screw driver...easy enough. thanks for all your guys help.

PaulD · 08-23-2004, 05:50 PM

yea, the alternator turns mechanical enrgy into electrical energy .... so it saps horsepower from your car when you are loading it down. If it's the factory alt, most cars have a "program" that change the idle to compensate for the additional load but it may not be enough if the alt is small and the draw is large.

Navy I.C. · 08-23-2004, 08:03 PM

I have a rewind shop at work, and we use it to get more power from the same old generators and motors without having to buy bigger more expensive equipment. it's the same concept for your alternator, if you can find a rewind shop in your area it might be worth it to look into rewinding your alt. or even adjusting the brushes will make a little bit of difference

Abell255 · 08-28-2004, 01:23 PM

I'm curious as to why my 94 probe takes so long to start. Before i had this system, it would start after a crank or so, now it cranks for 10 seconds, and then once started, it almost dies and then jumps to like 1100 rpms, and the stereo isnt on. Its not an idle issue, or an engine issue as it just started. The idle is 850 rpms. Could it be the alternator on its last days of its life? shitty........

PaulD · 08-29-2004, 01:28 AM

it may be because your battery is always discharged to some degree. Try putting it on a battery charger over night if you can and see if it helps

Navy I.C. · 08-29-2004, 11:20 AM

What I think your problem may be, is that your system wants more than your alt. can give and so it's taking from your battery. Your stock charging system, even though that's the way it's supposed to work in that situation, cannot keep up with the new demands from your car.
I'm not suggesting this as a solution, but this is what I did when I had that same problem on my '86 Supra. What I used to do was cut the sounds off before I started to park, and then made sure my ammeter read about 12-14 volts by revving the engine once or twice before I cut the engine. Another thing you can do is check for grounds. Even if it's small and barely making contact, that's enough to trickle your battery down to that slow starting area...

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