cap or second battery?
10-30-2003, 06:31 AM
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cap or second battery?
I used to have only one 400 watt amp and a pair of 6x9s. But i have upgraded to two amps, one 400 watts and one 600 watts bridged to a 12" sub. Now with the two amps when any bass comes in my lites dim VERY bad, also when my fan comes on the bass suffers also. I have been looking at differnt systems and i see that alot of people do not have caps instead they run a second battery. What do you guys think? 
10-30-2003, 08:38 AM
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Car: '90 Formula 350
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I would say do the cap first. A cap is made to store energy and release at high load (when the bass starts hitting hard). If the cap doesn't solve it get the battery too, then you will beable to rest assured that the amps are getting enough juice. I'm guessing just a cap will be enough though. My friend was running 2 300s and a 600 or 800 on a stock battery and no caps.
10-30-2003, 08:41 AM
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I'll add that I'm running (2) 1 farad caps and a yellow top optima along with my conventional battery. I have 2 1200.1 amps! And I don't see any light dimming as far as I can tell.
10-30-2003, 04:04 PM
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do you really need the farad caps now that you run a second battery though? I always like to think that your alternator is the best bet when upgrading do to dimming. Ive read from enough people that using a cap is like putting a band-aid on a broken arm. As for a second battery that may help, but if you alternator cant keep 1 charged how is it supposed to handle 2?
ill post a link to some information on caps, as soon i get home.
ill post a link to some information on caps, as soon i get home.
10-30-2003, 04:22 PM
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your alt is supposed to supply power to charge the battery, it is not ment to supply power surges that an amp needs to make bass. My alt is 90 amps, that is not the problem. If i upgrade to a 200 amp alt it still does the same thing, charges the battery. Even a bigger alt wont supply a surge current. The only reason people with huge systems install bigger alts is to charge the caps or extra batteries they install.
10-30-2003, 04:23 PM
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I still don't see how the alternator will help solve the problem totally. You could probably just upgrade the ground running from the battery to the motor and the power wire from back of alternator to the battery. If it's only effected when the bass hits that just means that the system is sucking to much power at that time... now if the battery goes dead with the system barely on we got more problems (new alternator and more batteries more than likely). The new wiring trick might work and save ya some cash.
I think a cap would solve the problem presonally. A alternator is just made to keep the battery full (think of it as a holding cell for power). When the battery starts to get low the alternator says, "Crap I need to start putting out power now and it helps recharge the battery." Then goes, "Ok, back up to max charge I can stop working now." But for spikes like if the headlights dim under bass that just means you're trying to pull to much power from the battery alone at that one time. A cap would store up energy and release it for that type of case.
As for my case... I'm an expection! I'm running 2 amps that have a max draw of 114 amps. That's 228 amps max draw in theory. That's why I had to get 2 caps and a yellow top. I would literally make my regular battery and alternator beg for me to kill them and put them out of their misery if I didn't.
I think a cap would solve the problem presonally. A alternator is just made to keep the battery full (think of it as a holding cell for power). When the battery starts to get low the alternator says, "Crap I need to start putting out power now and it helps recharge the battery." Then goes, "Ok, back up to max charge I can stop working now." But for spikes like if the headlights dim under bass that just means you're trying to pull to much power from the battery alone at that one time. A cap would store up energy and release it for that type of case.
As for my case... I'm an expection! I'm running 2 amps that have a max draw of 114 amps. That's 228 amps max draw in theory. That's why I had to get 2 caps and a yellow top. I would literally make my regular battery and alternator beg for me to kill them and put them out of their misery if I didn't.
10-30-2003, 06:46 PM
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I will quote this information about caps from another as rather than link to another forum and direct traffic away. Hopefully it saves a few people from spending 100 bucks on a cap that they could have spent toward sumthin else.
Yes often power and ground wiring under the hood can make a difference by themselves.
-"the big 3"-
alt to the battery
battery to the master fuse panel
battery to the chassis (ground)
-the truth about caps-
"The only purpose for a cap is to prevent a change in voltage. Just like inductors oppose change in current. Caps are used to "stiffen" the power supply to an amp, but it is more like putting a bandaid on a broken leg. For extremely short bursts, caps can help with "light dimming" in your vehicle, but that is it. They don't do anything else. They don't "add" more power to your stereo or electrical system, they merely try to stabilize the voltage going to your amps, and since they are passive devices, they don't do that very well either. If you want voltage stabilization, there are only a couple products that do this. One of them is the Jacobs Electronics Accuvolt. It is an active voltave regulator that eliminates variations in voltage, and filters noise. But if your electrical system is not capable of supporting the demands of your system, the Accuvolt won't help either, in fact it will worsten the problem by drawing more current the lower your vehicle voltage goes. It still does more than a cap. The only real solution is a bigger alternator. Period. Power in=power out. Besides, with the cost of high-end caps, you won't spend much more money on a solid high-output alternator (about $210, give or take). "
"Capacitors oppose a change in voltage, just as inductors oppose a change in curent (ELI the ICE man from electronics 101). Caps do nothing for current. The only devices that do anything for current capabilities are batteries (passive) and alternators (active). Adding a bandaid (capacitor) can help for very brief bursts, but they are not effective storage devices at all. With a typical .003 ohm internal resistance for a 1 farad cap, it is only effective for .003 seconds (one time constant R*C= 1 time constant), where the cap has lost 62.3% of its initial charge. By .015 seconds (5 time constants), the cap has lost 99.99% of its initial charge, being rendered completely useless. As a "current stabilization" device, they aren't even useless. They store a fraction of an amp. Their engineering is based upon voltage stabilization. That's why they are used in power supplies, because they do a decent job at stabilizing output voltages, as long as the current is present (hence the jumbo inductors in power supplies). I have heard every urban legend imaginable about capacitors, but it boils down to one thing: caps don't do very much at all. Current draw is current draw. If you draw more current than your alternator produces (including vehicle demands), your battery tries to compensate. That is the first warning sign. When your battery starts losing energy, your electrical system starts wavering (lights dim). Adding a $100 bandaid (a passive bandaid at that) isn't going to fix the problem. If you aren't generating the current to begin with, nothing will permanently solve the problem except to generate more current, and that means upgrading your alternator"
"The properties of a capacitor determine how it will work. ELI the ICE man is what all 1st year electronics students learn to help them remember what caps and inductors do in an electronic circuit. The capacitor is used to oppose a change in voltage in AC circuits, because the current leads the voltage through a capacitor. The current goes through the power wire connected to the cap (and the battery and amplifier). If there is no drop in the vehicle's electrical system, then the cap just sits there without doing anything. When you tax the alternator past its cpabilities, the vehicle voltage drops, causing a shift on the plates of the capacitor. The plates on a 1 farad capacitor are HUGE, and store a significant amount of electrons at a potential determined by the electrical system of the car (the alternator- 14.4 volts). When this voltage dips, the cap discharges its stored energy to try to keep the voltage constant (at 14.4 volts). When it does so, it releases all of its energy quickly (.015 seconds to discharge 99.8% of its initial charge). This provides a simulated "voltage source" for the amplifier, thus stabilizing the input voltage, if only for a fraction of a second. The current never goes through the cap.
The current does suffer during this process, due to the fact that the alternator can not maintain the current production necessary for the stereo system. Once that happens, the battery tries to fill in, which is why the voltage drops (battery voltage starts at about 12.8 volts, and goes down as the stereo beats it up).
The only reason why the alternator and battery are at different voltages is because the charging source needs to be >5% higher than the battery, plus the voltage the connecting wires drop on the way to the battery). The amp will draw the current it needs, regardless of the voltage present, until the voltage drops below 10 volts or so, when the amp shuts off. Otherwise, you would not see as many symptoms when you push your alternator hard.
The capacitor's only job is to maintain voltage in the stereo system, nothing else. It's fundamentally flawed design prevent it from doing this very well at all, except for extremely short bass bursts. The alternator still gets pounded, and the electrical system as a whole still gets abused when excessive current is required for the stereo system. If the amp is designed to draw 150 amps, come hell or high water, it will draw 150 amps, even if it means driving the vehicle's electrical system down to 9.5 volts to do it.
As I have stated on many posts, capacitors are bandaids. The only purpose for them is to provide extremely short periods of stabilization for burps and other quick bass demands. They do not offer solutions for anything except peace of mind (until more serious electrical problems arise). If you are drawing too much current from your electrical system, you will eventually face much more costly bills than your $100 cap (alternator, battery, master fuse panel, etc). That is my $25.02 (a little more than .02 )"
Yes often power and ground wiring under the hood can make a difference by themselves.
-"the big 3"-
alt to the battery
battery to the master fuse panel
battery to the chassis (ground)
-the truth about caps-
"The only purpose for a cap is to prevent a change in voltage. Just like inductors oppose change in current. Caps are used to "stiffen" the power supply to an amp, but it is more like putting a bandaid on a broken leg. For extremely short bursts, caps can help with "light dimming" in your vehicle, but that is it. They don't do anything else. They don't "add" more power to your stereo or electrical system, they merely try to stabilize the voltage going to your amps, and since they are passive devices, they don't do that very well either. If you want voltage stabilization, there are only a couple products that do this. One of them is the Jacobs Electronics Accuvolt. It is an active voltave regulator that eliminates variations in voltage, and filters noise. But if your electrical system is not capable of supporting the demands of your system, the Accuvolt won't help either, in fact it will worsten the problem by drawing more current the lower your vehicle voltage goes. It still does more than a cap. The only real solution is a bigger alternator. Period. Power in=power out. Besides, with the cost of high-end caps, you won't spend much more money on a solid high-output alternator (about $210, give or take). "
"Capacitors oppose a change in voltage, just as inductors oppose a change in curent (ELI the ICE man from electronics 101). Caps do nothing for current. The only devices that do anything for current capabilities are batteries (passive) and alternators (active). Adding a bandaid (capacitor) can help for very brief bursts, but they are not effective storage devices at all. With a typical .003 ohm internal resistance for a 1 farad cap, it is only effective for .003 seconds (one time constant R*C= 1 time constant), where the cap has lost 62.3% of its initial charge. By .015 seconds (5 time constants), the cap has lost 99.99% of its initial charge, being rendered completely useless. As a "current stabilization" device, they aren't even useless. They store a fraction of an amp. Their engineering is based upon voltage stabilization. That's why they are used in power supplies, because they do a decent job at stabilizing output voltages, as long as the current is present (hence the jumbo inductors in power supplies). I have heard every urban legend imaginable about capacitors, but it boils down to one thing: caps don't do very much at all. Current draw is current draw. If you draw more current than your alternator produces (including vehicle demands), your battery tries to compensate. That is the first warning sign. When your battery starts losing energy, your electrical system starts wavering (lights dim). Adding a $100 bandaid (a passive bandaid at that) isn't going to fix the problem. If you aren't generating the current to begin with, nothing will permanently solve the problem except to generate more current, and that means upgrading your alternator"
"The properties of a capacitor determine how it will work. ELI the ICE man is what all 1st year electronics students learn to help them remember what caps and inductors do in an electronic circuit. The capacitor is used to oppose a change in voltage in AC circuits, because the current leads the voltage through a capacitor. The current goes through the power wire connected to the cap (and the battery and amplifier). If there is no drop in the vehicle's electrical system, then the cap just sits there without doing anything. When you tax the alternator past its cpabilities, the vehicle voltage drops, causing a shift on the plates of the capacitor. The plates on a 1 farad capacitor are HUGE, and store a significant amount of electrons at a potential determined by the electrical system of the car (the alternator- 14.4 volts). When this voltage dips, the cap discharges its stored energy to try to keep the voltage constant (at 14.4 volts). When it does so, it releases all of its energy quickly (.015 seconds to discharge 99.8% of its initial charge). This provides a simulated "voltage source" for the amplifier, thus stabilizing the input voltage, if only for a fraction of a second. The current never goes through the cap.
The current does suffer during this process, due to the fact that the alternator can not maintain the current production necessary for the stereo system. Once that happens, the battery tries to fill in, which is why the voltage drops (battery voltage starts at about 12.8 volts, and goes down as the stereo beats it up).
The only reason why the alternator and battery are at different voltages is because the charging source needs to be >5% higher than the battery, plus the voltage the connecting wires drop on the way to the battery). The amp will draw the current it needs, regardless of the voltage present, until the voltage drops below 10 volts or so, when the amp shuts off. Otherwise, you would not see as many symptoms when you push your alternator hard.
The capacitor's only job is to maintain voltage in the stereo system, nothing else. It's fundamentally flawed design prevent it from doing this very well at all, except for extremely short bass bursts. The alternator still gets pounded, and the electrical system as a whole still gets abused when excessive current is required for the stereo system. If the amp is designed to draw 150 amps, come hell or high water, it will draw 150 amps, even if it means driving the vehicle's electrical system down to 9.5 volts to do it.
As I have stated on many posts, capacitors are bandaids. The only purpose for them is to provide extremely short periods of stabilization for burps and other quick bass demands. They do not offer solutions for anything except peace of mind (until more serious electrical problems arise). If you are drawing too much current from your electrical system, you will eventually face much more costly bills than your $100 cap (alternator, battery, master fuse panel, etc). That is my $25.02 (a little more than .02 )"
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10-30-2003, 07:56 PM
#8
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I guess all the demo cars and sound off cars dont have a clue what they are doing with all the extra batteries they run lol 
I think ill upgrad the wires under hood and add a larger battery since the one i have now is small.
I think ill upgrad the wires under hood and add a larger battery since the one i have now is small.
10-31-2003, 05:34 PM
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if you are gonna do it, do it right, get an optima, a good battery will do a better job of keeping the amplifiers fed, and get a better alternator.
a battery cant supply voltage that isnt there, the alternator is what keeps your car running.
adam
a battery cant supply voltage that isnt there, the alternator is what keeps your car running.
adam
11-02-2003, 10:18 AM
#11
Check your grounds, and make sure you have the proper size wire for your amps.
If your lights are dimming while the engine is running, adding a new battery isn't going to help, you'll actually make it worse if you try and have two batteries. Now instead of one battery for your alternator to keep charged, you have two. So that's just more of a strain on your system.
A cap, might help but its only a bandaid for what the real problem is. Your alternator is not supplying enough current to meet demands.
The reason the pros have all those batteries in the cars, are for either to have more engine off time, or just for show points.
Look into a higher output alternator, what amperage alt do you have right now?
Chris.
If your lights are dimming while the engine is running, adding a new battery isn't going to help, you'll actually make it worse if you try and have two batteries. Now instead of one battery for your alternator to keep charged, you have two. So that's just more of a strain on your system.
A cap, might help but its only a bandaid for what the real problem is. Your alternator is not supplying enough current to meet demands.
The reason the pros have all those batteries in the cars, are for either to have more engine off time, or just for show points.
Look into a higher output alternator, what amperage alt do you have right now?
Chris.
11-02-2003, 06:24 PM
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In comps you do not get extra points for having extra batteries. Also my alt is 90 amps, also my amp power wire is 4 ga. An alt is there to charge the battery and suply the power for the engine to run, it is not made to supply power that an amp needs to hit hard bass. SO yes you are correct in saying a second battery will not solve the problem, so maybe i should of made this post called "Cap Or bigger Battery" as this seems to be the real question. My underhood wires are not really the best size so maybe ill upgrade the wires and get an optima battery.
11-02-2003, 06:52 PM
#13
A bigger battery isn't going to help either, unless you are sitting there listening to your stereo with the engine off. All a battery is going to do for you is increase your engine off listening time.
A cap might help some, but like blyth18md said in a previous post. A cap is only a band aid for fixing the real problem.
Here is some helpful information for you to read about car electrical systems
http://pub14.ezboard.com/fcaraudiota...picID=23.topic
This article was written by one of my Mods at my car audio discussion board.
Also in comps where your installation goes toward your final score, people install the extra batteries to get the judges attention. If its a clean install and looks nice, you get extra points.
Chris
A cap might help some, but like blyth18md said in a previous post. A cap is only a band aid for fixing the real problem.
Here is some helpful information for you to read about car electrical systems
http://pub14.ezboard.com/fcaraudiota...picID=23.topic
This article was written by one of my Mods at my car audio discussion board.
Also in comps where your installation goes toward your final score, people install the extra batteries to get the judges attention. If its a clean install and looks nice, you get extra points.
Chris
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