Can you really get 20 farads for $100?/ - diyAudio
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Old 25th December 2008, 11:39 PM   #1
ppia600 is offline ppia600  United States
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Default Can you really get 20 farads for $100?/

I'm looking at throwing a 10 to 20 farad capacitor next to my earthquake amp and am kind of amazed they advertise these asian made capacitors for so cheap? Are they really the capacity they claim? There are so many random sizes (10,12,15,18,20, etc.) in the same shell, it makes me wonder if they are somehow cheating in the description.
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Old 26th December 2008, 12:18 AM   #2
Logikal is offline Logikal  United States
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Any particular reason you want a cap?

A cap discharge in a car audio system is basically like having a little battery that will discharge almost instantley once the amp cannot draw more load from the battery. You'll also run into a problem with the cap having to recharge which with 20 farads is no quick little charge. This causes the amp to not be able to draw the proper power consumption needed for full efficiency.

A better way to blow 100 dollars is to buy a second a battery or upgrade your current one to a Kinetic which are high output dry cell batteries. Also the alternator and all cabling should be upgraded to a higher gauge before you even consider a cap. This way you will have a much more stable system that will be upgradeable with minimal cost involved.

Just my two cents.

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Old 26th December 2008, 12:35 AM   #3
ppia600 is offline ppia600  United States
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Thanks for the reply


I already have excellent wiring. All underhood 12v cables are upgraded, including the alternator cable. The alternator is a 90 amp model. The problem is I'm running three amps... one earthquake phd2 (2krms), and two a600.2 (1.2krms), they are running at 4 ohms/chanel though so only around 1600rms capability theoretically. Each a600 has a 4gauge and the bass amp has two 4gauge. I'm already running a small agm battery under the hood which kicks the stock lead acid battery's butt. I already have the equivalent ot the 600 model under my hood now. I'm trying to avoid getting the 1800 amp version because of the weight.
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Old 26th December 2008, 01:35 AM   #4
Logikal is offline Logikal  United States
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With running all those wires without a distro block is not the best option. I would run one single 0/1 OFC cable to the rear and distro to each amp. This way you won't run into any high resistance problems as you are right now. Also, what are your grounding points like?
The 600 series is a baby battery used mainly in over the top systems as a backup only. It simply does not perform in a high output enviroment such as yours. How is the grounding on the amps? did you grind to bare metal and etch the ground or simply screw it into the sheet metal. A good choice for you is to create a grounding block out of some sheet metal and ground all the amps to one single point on a 12" piece of stock.
i was able to run dual Solobaric L7's with a zx1500.1 and a tang-band custom component setup up front and dual zx350.4 on a stock alternator with no cap and only a 600 as a backup with zero voltage drop on full load.
Another reason many people feel they need to have a cap is because they do not have the gain properly set. Did you tune it by ear or use a voltmeter.
With that system I see no reason why you would ever need to have a cap. It would cause you more headache then what it would be worth.
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Old 26th December 2008, 02:26 AM   #5
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Buy a US made REAL Ultra Cap see below:

http://cgi.ebay.com/ws/eBayISAPI.dll...MEWA:IT&ih=012


These sell for new at about $209.00 each for 58 farad You won't find any deals like that from a car stereo maker even in China...Good luck, oh just goggle the name brand and dealers will pop up in your search for these US made products...Merry Christmas....
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Old 26th December 2008, 02:36 AM   #6
ppia600 is offline ppia600  United States
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Quote:
Originally posted by Logikal
With running all those wires without a distro block is not the best option. I would run one single 0/1 OFC cable to the rear and distro to each amp. This way you won't run into any high resistance problems as you are right now. Also, what are your grounding points like?
The 600 series is a baby battery used mainly in over the top systems as a backup only. It simply does not perform in a high output enviroment such as yours. How is the grounding on the amps? did you grind to bare metal and etch the ground or simply screw it into the sheet metal. A good choice for you is to create a grounding block out of some sheet metal and ground all the amps to one single point on a 12" piece of stock.
i was able to run dual Solobaric L7's with a zx1500.1 and a tang-band custom component setup up front and dual zx350.4 on a stock alternator with no cap and only a 600 as a backup with zero voltage drop on full load.
Another reason many people feel they need to have a cap is because they do not have the gain properly set. Did you tune it by ear or use a voltmeter.
With that system I see no reason why you would ever need to have a cap. It would cause you more headache then what it would be worth.
Frankly I prefer seperate wires for each amp directly from the battery versus splitting one. Every amp has sufficient wire gauge, its more of a lack of power from under the hood problem. I won't go over my setup as it gets old explaining it several times. I've posted it before so if you're really trying to find any other flaw in my wiring you can find it in a search.
The purpose of this thread was to discuss the possibility of a cheap priced capacitor having the actual claimed farad level, not to start a discussion on my audio system. I appreciate if you're trying to help, but I'm not looking for wiring advice, simply trying to see if anyone has opinions on the build quality of random cap brands. I know the technological capability is there to use carbon/foil/aluminum caps and get high farad capacity, I just want to know if they are legit.
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Old 26th December 2008, 02:38 AM   #7
ppia600 is offline ppia600  United States
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Quote:
Originally posted by 1moreamp
Buy a US made REAL Ultra Cap see below:

http://cgi.ebay.com/ws/eBayISAPI.dll...MEWA:IT&ih=012


These sell for new at about $209.00 each for 58 farad You won't find any deals like that from a car stereo maker even in China...Good luck, oh just goggle the name brand and dealers will pop up in your search for these US made products...Merry Christmas....

Wow, interesting. Those 2.7v caps are the ones batcap has been using for a few years now. I disassembeled one a few years ago when my friend bought it and was amazed at the capacity of each 2.7v cap, and how they series and paralleled several to get the correct farad and voltage rating.
I'm sure the cheapo cap companies have access to those but whether or not they actually use enough to create the stated capacity is questionable.
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Old 26th December 2008, 03:12 AM   #8
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Yup These are the real deal as used in electric cars. I even saw a motorcycle powered off these the only draw back being that the electric motor fried itself on every pass at the track at about 250 MPH...

Maxwell makes nothing but high capacity capacitors to my knowledge so i would guess that they are very legit. I have the schematic for those Alumapro/PG carbon caps and they all use a huge bank of 2.7 volt caps to get the value that they spec.
They either use active or passive voltage balancing to keep the separate caps from getting more voltage then rated. but I have seen these car amp caps blow them selves up because of this.

If you look at the specific one I posted from e-bay you will see it has less separate caps then the ones car amp companies sell. Less parts usually means lower failure rates of the device.

Plus at 58 farad per unit, and bought directly from the maker of even through a dealer they cost less per farad that ANYTHING a car amp company offers by at least half and more like two thirds the cost of a comparable Alumapro product on the market.
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Old 28th December 2008, 03:40 AM   #9
ppia600 is offline ppia600  United States
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I was pondering replacing my underhood battery with one about twice the size and moving the small one next to the bass amp. I checked kinetik's battery website. For a system running 3200 watts rms they recommended:
(1) kc1600 under the hood
(2) kc1800's near the bass amp

I lol'ed.... 150 extra lbs in my car, NOT!

Maybe just the 1600 or 1800 under the hood and my small one in the trunk, but if that doesn't help substantially I'll look into an overpriced 140 amp subaru alternator. First I'm going to check the parking light system grounds and power connections. There is the possiblility they aren't getting a good connection since the hid headlights aren't even flickering or going into protection, which means they're recieving plenty of voltage.
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Old 28th December 2008, 04:18 AM   #10
ppia600 is offline ppia600  United States
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Oops, I meant khc1400 instead of 1600, my bad
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