I'm not sure why people buy those "car audio" capacitors when computer-grade capacitors have a lower ESR, higher current rating and can dump all of their energy near-instantly without damage.
Here is a picture of my capacitor bank. Since my hobby is a bit different from yours it's a 700V 24800uF bank, but the same construction would apply to low voltage capacitors. Although if you get a big enough capacitor you wouldn't even need busbars. Large real caps do exist, such as the 1F 25V cap on this vishay datasheet.
Here is a picture of my capacitor bank. Since my hobby is a bit different from yours it's a 700V 24800uF bank, but the same construction would apply to low voltage capacitors. Although if you get a big enough capacitor you wouldn't even need busbars. Large real caps do exist, such as the 1F 25V cap on this vishay datasheet.
Computer grade caps are OK. Well designed and what not for their intended purpose, but they usually cost significantly more then the typical grade devices used by most audio manufacturers. And they are usually huge size wise in a use where small size is very important. It's all a matter of build costs and physical size limitations IMHO. Also most likely due to limited discharge rates required for audio, and the huge discharge rates and internal heat build up for industrial usages like lasers, flash tubes, and rail gun technology's.
Plus in large banks like yours, variances in ESR and voltage drop across each individual capacitor comes into play and usually requires some form of active or passive control method such as resistors < passive> or diodes < active> to equalize drops and current sharing issues associated with very large capacitor arrays.
I don't claim to be anywhere near expert in the area but, in most cases where large arrays of any device are used, high precision tolerance matching usually comes into play so each individual device performs equally, and or some active or passive matching networking is designed into the scheme just to maintain electrical uniformity of operation. This includes those large SUPER caps used in electric cars also. They even advertize either active or passive methods in their option spec's. Presumably due to their extensive use of very large cap arrays such as yours. Since they manufacture cap banks I am guessing they have a firmer grip on the technology then me.
PS the largest cap bank I ever saw was at the Lawrence Livermore Labs used on the Fusion project they have going on their. < it's online if you care to take a look, just Google Fusion LLL > The cap bank was the size of a high school gym as I recall. The steel beams were coated with fire retardant just in case the room was to go up in flames so the steel would have some fire/heat protection for a while.
I am guessing by your 700 volt rating your either into high power discharge devices such as laser's and flash tubes or perhaps small rail gun technology. All very neat stuff...Most car and home audio is designed and built on a much lower level of technology, with a very high safety factor involved.
Large cap array's can be very volatile upon failure, Fire, explosions and so on. This is also probably another reason why you don't see such huge efforts at energy storage in audio. it can be very dangerous to the inexperienced and unqualified..
Plus in large banks like yours, variances in ESR and voltage drop across each individual capacitor comes into play and usually requires some form of active or passive control method such as resistors < passive> or diodes < active> to equalize drops and current sharing issues associated with very large capacitor arrays.
I don't claim to be anywhere near expert in the area but, in most cases where large arrays of any device are used, high precision tolerance matching usually comes into play so each individual device performs equally, and or some active or passive matching networking is designed into the scheme just to maintain electrical uniformity of operation. This includes those large SUPER caps used in electric cars also. They even advertize either active or passive methods in their option spec's. Presumably due to their extensive use of very large cap arrays such as yours. Since they manufacture cap banks I am guessing they have a firmer grip on the technology then me.
PS the largest cap bank I ever saw was at the Lawrence Livermore Labs used on the Fusion project they have going on their. < it's online if you care to take a look, just Google Fusion LLL > The cap bank was the size of a high school gym as I recall. The steel beams were coated with fire retardant just in case the room was to go up in flames so the steel would have some fire/heat protection for a while.
I am guessing by your 700 volt rating your either into high power discharge devices such as laser's and flash tubes or perhaps small rail gun technology. All very neat stuff...Most car and home audio is designed and built on a much lower level of technology, with a very high safety factor involved.
Large cap array's can be very volatile upon failure, Fire, explosions and so on. This is also probably another reason why you don't see such huge efforts at energy storage in audio. it can be very dangerous to the inexperienced and unqualified..
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Lower voltage high capacitance caps were more difficult to manufacture but are getting more inexpensive. The higher voltage lower capacitance ones have been easier to make for ages and of course you can get them for less. You can build a large bank with electrolytics or carbon foil types but by the time you add in material cost, size, and performance for the same single aftermarket version you end up spending more. Why would you buy sixty kazillion electrolytic (or carbon) smaller capacitors and spend all of the time fitting and building the rail system and even having to design the resistor equalizing circuits mentioned above when you could just buy one 20-25farad low voltage cap for $100? I'm not saying I like sending $100 to some random asian factory but I also don't want $15-20lbs of stuff taking up space in my vehicle that I could be using for other things. Yeah, individual "super" or "ultra" caps seem cheap but multiply how many you will need to achieve the same capacitance times the other materials and time you spend building it. Yeah, its nice that we can build them but why?
as long as its not a tiny flooded plate lead acid battery, agm's are best imo
I do as well but high farad caps are great at filtering ripple from the alternator, and are getting smaller.
Caps are not useless, so much heresay in this thread. Have you ever tried batcaps? "If its on teh intarwebz it must be true"
Here you go guys. Some ULTRA CAPS
Electric double-layer capacitor - Wikipedia, the free encyclopedia
I like bat caps and have recommended them a many a time in the past, but not since these puppies became available. Their is a guy selling a 7 cap stack and he starts a diesel engine with them. And another fella on tube runs a color 32 inch tube tv for 10 minutes with a 5 stack of the 2600 farad units, its only about 500 farad real world at 12 volts to a inverter.
Be fore warned though, don't allow any one of these individual caps see over 2.5 volts Dc to them. You have to stack them for higher voltage use. I even saw a 125 volt and a 48 volt one on that auction site. Pre-built ready to run, and about 180 pounds to lift and carry...Yes Sir ULTRA CAPS
Oh and don't forget the voltage balancing circuitry across the cap stacks to keep the voltage to each cap at or below 2.5 volts max. This is that balancing circuitry I mentioned in my earlier post. It is very important for safety and life expectancies reasons if you build a stack of these puppies...and please be very careful when working with large capacity systems...
Electric double-layer capacitor - Wikipedia, the free encyclopedia
I like bat caps and have recommended them a many a time in the past, but not since these puppies became available. Their is a guy selling a 7 cap stack and he starts a diesel engine with them. And another fella on tube runs a color 32 inch tube tv for 10 minutes with a 5 stack of the 2600 farad units, its only about 500 farad real world at 12 volts to a inverter.
Be fore warned though, don't allow any one of these individual caps see over 2.5 volts Dc to them. You have to stack them for higher voltage use. I even saw a 125 volt and a 48 volt one on that auction site. Pre-built ready to run, and about 180 pounds to lift and carry...Yes Sir ULTRA CAPS
Oh and don't forget the voltage balancing circuitry across the cap stacks to keep the voltage to each cap at or below 2.5 volts max. This is that balancing circuitry I mentioned in my earlier post. It is very important for safety and life expectancies reasons if you build a stack of these puppies...and please be very careful when working with large capacity systems...
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Here you go guys. Some ULTRA CAPS
Electric double-layer capacitor - Wikipedia, the free encyclopedia
I like bat caps and have recommended them a many a time in the past, but not since these puppies became available. Their is a guy selling a 7 cap stack and he starts a diesel engine with them. And another fella on tube runs a color 32 inch tube tv for 10 minutes with a 5 stack of the 2600 farad units, its only about 500 farad real world at 12 volts to a inverter.
Be fore warned though, don't allow any one of these individual caps see over 2.5 volts Dc to them. You have to stack them for higher voltage use. I even saw a 125 volt and a 48 volt one on that auction site. Pre-built ready to run, and about 180 pounds to lift and carry...Yes Sir ULTRA CAPS
Oh and don't forget the voltage balancing circuitry across the cap stacks to keep the voltage to each cap at or below 2.5 volts max. This is that balancing circuitry I mentioned in my earlier post. It is very important for safety and life expectancies reasons if you build a stack of these puppies...and please be very careful when working with large capacity systems...
Batcaps are comprised of several ultracaps in series including the voltage equalizing circuits.
Really? Never heard about high esr with them...
Ummm, it has nothing to do with internet. There useless in spl cars because there just another circuit for current travel through before reaching the amps. It's known fact and it's why no one for last twenty years has used them for DB Drag or SPL. DB Drag systems use there energy in short bursts so a direct shot from batteries has always been the preferred method. Yea internets
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quoted from wiki
Very high rates of charge and discharge.
Extremely low internal resistance (ESR) and consequent high cycle efficiency (95% or more) and extremely low heating levels
High output power
High specific power. According to ITS (Institute of Transportation Studies, Davis, California) test results, the specific power of electric double-layer capacitors can exceed 6 kW/kg at 95% efficiency[10]
Improved safety, no corrosive electrolyte and low toxicity of materials.
Simple charge methods—no full-charge detection is needed; no danger of overcharging.
Batcaps are comprised of several ultracaps in series including the voltage equalizing circuits.
Humm. I never torn one open, but I was always under the idea that they were very fast battery's such as rapid-charging lithium-titanate batteries and the like. Now some of those super car battery's I have seen torn open and they were indeed stacks of bat caps.
They solved a whole bunch of customer complaints for me in the past mostly do to very poor electrical systems people try to use for high powered car audio systems.
My swing to ultra caps was solely based on power storage efficiency and heat related failures that most commercial car audio solutions were prone to. This and the fact when jumping to say Maxwell caps your taking out all the middle men trying to market things to you. By going to the manufacture source you can save lots of middle man costs and marketing hype.
Well with the efficiency of Class D circuitry I still can't see a need for a daily driven system even up to 2k watts to use a cap. Higher amp alternator and a secondary battery have proven time and time again to be a better source of constant power. I have seen the batcaps and only a few people used them in spl to my knowledge but for daily use a better alt is always going to better then adding batteries or caps. Anyway it's my personal take that caps for car audio are waste when used for power storage, not because the internet or people in competition say so but from personal experience.
Well I define low ESR as enough to explode whatever you short the cap into.
As far as capacitors go, EDLCs have a very high impedance, but compared to standard batteries it's rather low.I think a cap can work for a music system, where a peak is fed and the cap has time to recharge. For SPL, you would need a lot of cap to burp and large alt works better. I have a 1f I got very cheap and going to put it in more for noise and surge issues since I have it. I don't have any noise but way I see it what could it hurt, and might be good for my stock alt. I only get dimming if I really pound my system, which I rarely do at night and not that often in the day lol. My other idea was to run a jumper pack in the trunk and have it connected for spare power to the amps, but with the class D amps I am running now it is hardly an issue.
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