When used close to an amplifier their main purpose is for keeping tight power transients for musical peaks, you don't need a huge battery for this. An auxiliary battery is mainly for extended power draw during competitions for continuous spl purposes or for avoiding dead batteries when running the stereo for longer periods of time with the car not running. You of course can use ten uber huge batteries and eliminate the need for an external cap but for most people using that in their daily driver wouldn't be practical. That is where an external capacitor with its relatively light weight and smaller size comes into play.
If batteries were more superior for sq/voltage stabilization purposes they would be in the amplifier voltage rails instead of caps. For the same size and weight a battery can't release all of its energy as quickly as a capacitor, even normal electrolytics are quicker. And "super" and "ultra" caps are leaps and bounds ahead of electrolytics. The ideal system has both, with a high farad cap closest to the amplifier.
If batteries were more superior for sq/voltage stabilization purposes they would be in the amplifier voltage rails instead of caps. For the same size and weight a battery can't release all of its energy as quickly as a capacitor, even normal electrolytics are quicker. And "super" and "ultra" caps are leaps and bounds ahead of electrolytics. The ideal system has both, with a high farad cap closest to the amplifier.
Last edited:
Well I define low ESR as enough to explode whatever you short the cap into.
Humm .. not the typical industrial standard, but if it works for you, then I say go for it.
Although I feel that the "explosion" itself would better be considered as some viable measurement of total energy released into the test rather then a realistic measurement of ESR.
where did you get a 100ah agm battery that wasn't an overpriced "car audio" version?! all i could find when i was looking was small capacity ones.
I found a good deal on a used kinetic battery locally but I want something with about 4x the capacity as the one i have (50ah iirc)
Supposedly a cap will support 14v from the alt not 12v from the battery (for unregulated amps), but right you need tons of them to run an amp at SPL level even for a moment.
Have seen many reports it cured a noise issue, and some say it is better for the alternator as well as other devices in the car as it should provide a cleaner power source for everything. Way back when I installed we used to put caps on stuff all the time for noise, smaller ones of course, often on head units. Yeah, we used to blow them up once in a while too for entertainment.
Have seen many reports it cured a noise issue, and some say it is better for the alternator as well as other devices in the car as it should provide a cleaner power source for everything. Way back when I installed we used to put caps on stuff all the time for noise, smaller ones of course, often on head units. Yeah, we used to blow them up once in a while too for entertainment.
Yep head-units are what we used them for to. I know Mark Fakuda used them in his cemented out SPL truck only for his head-unit. In this thing
An externally hosted image should be here but it was not working when we last tested it.
Take one of your largest amps and add up the total capacitance on the 12v storage section. Then divide those into a 25farad cap to see how many of those you would have to have to equal that one external. You may be surprised.
The internal caps are still normal electrolytics and only a small fraction of storage compared to what a decent external ultra/super cap would be. External caps have come a long way. When the car audio versions came out they were .5 to 1 farad electrolytics, now you can get a 20 farad hybrid for the same price a 1 used to be and they are not much larger. I'm not saying capacitors are miracle workers but what they did back then they do way better nowadays. The benefits were blown out of proportion when they first came out in my opinion and I think that left a bad taste in peoples' mouths that they can't seem to forget. When I was in sales & installation, I never doubted their benefit but also never claimed them to work miracles.
Last edited:
The caps that are inline with the power section of the amp are not for storage.
Yeah I have to agree most all amps use 12 volt caps to filter out the power supply switching noises the amp creates. Without them you will most likely blank out AM and FM radio reception in both your car and the others near by you at a stop light.
I remember field upgrading some of the very first M-44's out of PG with new power toroid's with different windings and adding Zobel networks across all the diodes to render even brand new amps RFI and EMI safe. Seems they were broadcasting anytime they were turned on lol..funny as all get out at the time..lol.
Only a few very special amps like the 15KW RF amp and the Special limited edition carbon fiber multi-channel amps from PG ever had huge 12 volt caps added to them. And even then all they were doing was compensating for very poor battery loading time delay lag issues of stock car battery's and older Alternators back then...
If you want stereo and don't want to modify your vehicles electrical power system then some caps and the bat caps are a gift from the audio God's. As they will HELP you to get over the fact your vehicle maker did not intend for you have or use high fidelity gear in your vehicle. I just wish folks would get sold the right bill of goods by salesmen and also have their electrical systems upgraded also when they add all that boom to their rolling box...
I remember field upgrading some of the very first M-44's out of PG with new power toroid's with different windings and adding Zobel networks across all the diodes to render even brand new amps RFI and EMI safe. Seems they were broadcasting anytime they were turned on lol..funny as all get out at the time..lol.
Only a few very special amps like the 15KW RF amp and the Special limited edition carbon fiber multi-channel amps from PG ever had huge 12 volt caps added to them. And even then all they were doing was compensating for very poor battery loading time delay lag issues of stock car battery's and older Alternators back then...
If you want stereo and don't want to modify your vehicles electrical power system then some caps and the bat caps are a gift from the audio God's. As they will HELP you to get over the fact your vehicle maker did not intend for you have or use high fidelity gear in your vehicle. I just wish folks would get sold the right bill of goods by salesmen and also have their electrical systems upgraded also when they add all that boom to their rolling box...
It's a C&D High Rate series UPS battery. I picked up 2 at AMVETS for $10 each. It's a $250 battery! AGMs aren't cheap, but they are electrically awesome and reliable. Luckily they still worked just fine.
Those batteries have an impedance of 2.05mohm so at 12V they can supply peak currents of 5.8kA. They are only rated for a continuous 800 amps though (but that's still 9.6kW).
I was thinking you were referring to the input section side of the power supply, not the output side (audio section). My bad.
You are correct about the primary caps on the input side not being for primary power storage, but they do store energy when input voltage sags and smooth it when input voltage rises... to keep input voltage more steady / filter / help keep clean dc and remove ac components of alternator output.
If you don't want to count those, count the ones on the output section of the power supply then, where the high voltage caps are. You still only have a tiny fraction of what the average external cap can produce.
I run a tiny agm under the hood and another tiny one in the trunk. Helps weight distribution, helps clear fmic piping, and both combined provide more than enough cranking power and audio system reserve. Agm's are awesome and I can't wait until all car manufactures stop using crappy huge flooded plate batteries.
Last edited:
Which is why most people just beef up alternator and/or add batteries. It's just a matter of math. Ohm's law. If I have a 2000watt rms amp 1ohm mono class d (for subs) I'll assume it's at the minimum 70% efficient then I know it's max amp pulling ability at it's lowest impedance should be around 120amps so if the rest of car's electrical at full throttle is pulling 80 amps then I would be looking at a 200amp maximum pull or need on the electrical. buying a alternator that can do 225 to 250 at 2000 rpm should handle it all day even at a red light where the battery will get beat on most. Anyway we could go at this all day back and forth. Yes you can buy a cheap 1,2,5,20 farad cap and call it a day. It's matter of preference at this point.
I have a USA2000x and a USA400 in my civic, no extra battery, no caps, no dimming, go figure
A 20-25 farad cap is obviously not going to cost what a 225-250 amp alternator + who knows what kind of "upgraded" batteries costs so I don't know why you keep comparing them. "Most" people don't buy upgraded alternators, some buy upgraded batteries and some add another battery. Buying a $100 cap is not even in the same ball park as far as price is concerned. Of course if you have an alternator that is producing 250 continuous amps of current and a decent battery setup and your total vehicle vehicle draw doesn't exceed 250 amps then obviously you can play it "all day even at a red light" but "most" people don't have that kind of scratch to dedicate to that kind of extra equipment and some don't have the skills to install it correctly. As far as the dimming light issue goes, it doesn't always have to do with the alternator you have or having a system that exceeds that alternator's constant output capability. Sometimes it is insufficient vehicle wiring to support that power draw, incorrect amplifier power wiring or faulty/old/corroded vehicle wiring and/or connections. I never mentioned light dimming and never claimed a capacitor would stop that so why you use that as an example of how well your system is setup eludes me.
I don't get why you keep comparing upgraded batteries (and now you're adding high current alternators) to a relatively low priced capacitor add on. I'm not claiming capacitors are magical or that they cure anything but I know for a fact they do help. I am fully aware of how power creation and consumption are determined and you don't have to quote anything related to Ohm's law or mathematics. I also never mentioned any capacitor below 20 farads because the 1-6 farad types are usually the outdated electrolytic type and for the space used the newer types are more efficient.
So what alternator and battery are you using and what do they go for new?
I don't get why you keep comparing upgraded batteries (and now you're adding high current alternators) to a relatively low priced capacitor add on. I'm not claiming capacitors are magical or that they cure anything but I know for a fact they do help. I am fully aware of how power creation and consumption are determined and you don't have to quote anything related to Ohm's law or mathematics. I also never mentioned any capacitor below 20 farads because the 1-6 farad types are usually the outdated electrolytic type and for the space used the newer types are more efficient.
So what alternator and battery are you using and what do they go for new?
Last edited:
No, you are claiming that they are magical. No one who invests in high watt systems is going to waste money on caps, there useless for power storage no matter how many ways you try and explain it. There band-aids for an obvious lack of power. The 20 to 50 farad ones are 3-400 dollars for a good one. You can get ohio generator, or arragi or mechman alts for the same price. So why would you waste money on a useless, outdated storage method and try to convince people here that there's some new materials in them that somehow defy physics? Keep trying though.
Here's the link to Clarks reason for caps being useless Reasons why caps dont work by Richard Clark - Chevy Truck Forum | GMC Truck Forum - GmFullsize.com
Doubt you'll read it because once people buy into industry smoke and mirrors they'll defend it till death. I'm unsubscribing from this thread. Your not convincing me or anyone else for that matter of there usefulness in the car audio environment unless they already don't have a clue. I'm done wasting my time, just like the last thread on db drag classes you can win this one by posting another novel which no one else is going to read.
Doubt you'll read it because once people buy into industry smoke and mirrors they'll defend it till death. I'm unsubscribing from this thread. Your not convincing me or anyone else for that matter of there usefulness in the car audio environment unless they already don't have a clue. I'm done wasting my time, just like the last thread on db drag classes you can win this one by posting another novel which no one else is going to read.
No, you are claiming that they are magical. No one who invests in high watt systems is going to waste money on caps, there useless for power storage no matter how many ways you try and explain it. There band-aids for an obvious lack of power. The 20 to 50 farad ones are 3-400 dollars for a good one. You can get ohio generator, or arragi or mechman alts for the same price. So why would you waste money on a useless, outdated storage method and try to convince people here that there's some new materials in them that somehow defy physics? Keep trying though.
Yeah, hybrid caps are "useless, outdated".
They actually utilize some of the most state of the art technology available. Why do you keep dumping on caps, did one blow up in your face as a child? Did someone convince you to put your tongue on one to see if it was charged? Electric double-layer capacitor - Wikipedia, the free encyclopedia
NREL: Energy Storage - Ultracapacitors
MIT Builds Efficient Nanowire Storage to Replace Car Batteries - Popular Mechanics
You are putting words in my mouth and they don't even taste good.
A true 20farad cap is $80-100 no matter how you try and twist things to make the alternator price range closer. Of course you can spend more on a "better" name brand but specs are specs. No one here is saying alternators and extra batteries aren't worthwhile but for some reason you apparently want to crap on the idea of using a capacitor. They aren't for long term storage but they DO release their power quicker than any battery out there regardless of whether you believe it or not. They have lower esr and charge and discharge quicker than batteries, period. I'm not saying the total energy storage per size of a capacitor vs battery is the same but the capacitor will allow all of its power to be discharged much quicker and that is the benefit. REAL world music that people listen to while driving around isn't one constant 35hz bass note with no dynamics, it is constantly changing and contains transients and dips. When those peaks occur, a proper capacitor will supply the current quicker than a battery can release it or an alternator can produce it. Again I'm talking about real world situations with people listening to actual music and not bass mechanik, magic mike, bass 808, etc. You can always screw your amplifier two inches away from your main battery, connect it with 2/0 power and ground wire and put your subs two inches from the amp with 1/0 and then claim a cap will be useless. YES, it won't make much of a difference in this situation. But considering there is usually a distance of power wire between the amps and whatever battery is closest to them, the capacitor can supply extra stability if connected directly to the amp terminals with short thick wiring. Also consider the fact that many people utilize chassis ground and don't run uber huge ground wires directly from the battery to the amp terminals. Not everyone runs 2000wrms and up, or wants to spend $350 and up for an upgraded alternator. Most people simply don't need one. I even have a high current alternator and two agm batteries (very small, one under hood and one in trunk) but that is because I have a phd3 and adcom 5450. Not everyone needs to spend as much or have as much spl or constant use capacity to be satisified.Saying a capacitor is pointless though is going from one extreme to another. That's almost like a guy with a mustang wanting to add a better filter and exhaust to gain a few ponies and spending xxx amount and then someone saying "No, you're doing it all wrong. Those are just a bandaid, you need a supercharger running 10psi, forged pistons and internals, front mount intercooler, 4" exhaust tubing, etc.. or you're just wasting your time"
Catch my drift?
Last edited:
- Status
- This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.