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Thread: Is A Capacitor Necessary??? |
    
New member Username: Raydizzle34
Post Number: 6
Registered: Aug-08
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| Posted on Thursday, November 13, 2008 - 03:03 am: |
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I have the following items I want to install in my 2000 Ford Ranger...
Kenwood KDC-X492 Receiver
2 Kenwood KFC-W3011 12" Subs rated at 400 Watts RMS each
Kenwood KAC-9104D 900 Watts RMS at 2 ohms
I am planning on wiring my subs in parallel so that I get the 900 watts from my amp. But do I need to get a capacitor for my truck? What is the purpose of the cap? If I do need one, what size and brand should I get?
Thanks in advance for your guys' help! |
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New member Username: Deusle
Post Number: 5
Registered: Nov-08
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| Posted on Thursday, November 13, 2008 - 10:03 am: |
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capacitors store energy so the voltage of your electrical system doesnt drop at such a fast rate when an amp requires a lot of power (i.e. a bass note)
i just hooked up my friends 2 kenwood 400w rms subs in parallel last night and hes got a 2000W amp and his headlight dont even dim that much.
Capacitors make it easier on your alt + batt but are generally a waste of money, plus it takes power to charge it so the sub isnt seeing at much power as it could be.
But a good rule of thump for capacitors is "1 Farad for ever 1000W RMS." so a 1 farad cap would be optimal for your setup.
Just save up the money you would be spending on a capacitor for either thicker power cables to the amp, a high output alt, or an extra battery in the back.
makes no sence to get something that stores power if your not supplying enough power to it in the first place. |
Gold Member Username: N2audio
Lawrence,
Ks
USA
Post Number: 1685
Registered: Mar-04
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| Posted on Thursday, November 13, 2008 - 04:15 pm: |
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a cap is never a necessity.
They are an accessory.
They have a purpose, but they are of no significant benefit to your electrical system.
900w should not tax the alternator in a Ranger. |
Gold Member Username: Nd4spd18
Philadelphia,
PA
Post Number: 8945
Registered: Jul-06
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| Posted on Thursday, November 13, 2008 - 07:41 pm: |
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Capacitor is not needed nor does it give you any benifit. |
Platinum Member Username: Wingmanalive
A pic is worth
1000 posts!!
Post Number: 18920
Registered: Jun-06
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| Posted on Thursday, November 13, 2008 - 09:34 pm: |
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There is no substitute for an adequate charging system. Unless you can produce the watts don't expect to keep drawing them without paying the price.
Think of it like a college kid with his dad's credit card. Who pays the price at the end of the month? |
New member Username: Raydizzle34
Post Number: 7
Registered: Aug-08
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| Posted on Thursday, November 13, 2008 - 10:05 pm: |
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Paul, so should I get the 1 farad cap? |
Platinum Member Username: Wingmanalive
A pic is worth
1000 posts!!
Post Number: 18930
Registered: Jun-06
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| Posted on Thursday, November 13, 2008 - 10:19 pm: |
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Don't get ANY cap. They are only an even further burden to your charging system. They have their uses but are not intended to replace the proper charging a proper alt can provide.
http://www.glasswolf.net/papers/capacitors.html |
Platinum Member Username: Wingmanalive
A pic is worth
1000 posts!!
Post Number: 18931
Registered: Jun-06
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| Posted on Thursday, November 13, 2008 - 10:21 pm: |
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From above:
"So by adding a capacitor to try taking the place of a high-output alternator, you are actually causing more work for your alternator, and causing even more damage to that stock alternator."
It's been said by others above. |
New member Username: Raydizzle34
Post Number: 9
Registered: Aug-08
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| Posted on Friday, November 14, 2008 - 12:59 am: |
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Do I need to get a high-output alternator for only 900 Watts RMS? |
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Bronze Member Username: The_mod
BANVILLE
USA
Post Number: 41
Registered: Feb-08
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| Posted on Friday, November 14, 2008 - 01:09 am: |
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a cap (in most cases) is useless.
save your $ and by a battery. |
Gold Member Username: N2audio
Lawrence,
Ks
USA
Post Number: 1686
Registered: Mar-04
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| Posted on Friday, November 14, 2008 - 11:47 am: |
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Ray - From what I can find your ranger has a 95A alt, and probably a fairly light demand stock electrical system.
My old Tbird had a 75A alt, pwr windows, seats, ABS, fog lights, dual elec. radiator fans (a pretty extensive stock electrical system).
I ran 1100w w/o much trouble (low voltage at idle, but fine while driving.) After 2 years, and at 226K that alt finally let out the smoke. I replaced it with a 110A and that was a STRONG alt.
What I'm trying to tell you is 900w should not be terribly stressful for your alternator. Especially if you don't blast it all the time.
If you read around you'll see there are countless people on the various forums running 1000-1500w on stock charging systems.
On the surface 1000w seems like it would require a ton of current, but amplifiers do not produce thier rated power constantly. The average power is actually a small fraction of what the amp is capable of. |
New member Username: Raydizzle34
Post Number: 10
Registered: Aug-08
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| Posted on Sunday, November 16, 2008 - 04:04 am: |
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Thank you guys for the info. I installed the equipment in my truck tonight and it sounds great. My lights dim a little when I have the gain on the amp up and the subwoofer level up on my head unit but it's not too bad.
I might look into a higher output alternator. Thanks again you guys |
Gold Member Username: N2audio
Lawrence,
Ks
USA
Post Number: 1687
Registered: Mar-04
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| Posted on Monday, November 17, 2008 - 12:42 pm: |
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FWIW - Gain isn't a volume knob.
It is to adjust the senstivity of the amp to allow for the voltage of the signal coming into it from the HU. The idea is to get maximum unclipped output from the amp with your HU at it's maximum, unclipped volume setting (usually 75-90%).
Your HU has 4v signal strength so your gain should be somewhere in the 2-4v range.
Anything further clockwise on the sensitivy dial and you're just increasing the likelyhood of damaging your equipment while getting no benifit in SQ or SPL.
Also - for best results it's best to use little if any bass boost, LPF in the 70-100 range, and ISF at 25 if your enclosure is ported, 15 or off if it's sealed. |
