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Old 31st December 2007, 05:28   #1
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Default Capacitor? Need to stabilize voltage

Have seen lot of high end Audio setup's use Capacitors for their AMP's. I would like to know how it is wired in the system? is it Load specific ? Current specific? AMP Specific? How do you choose what size capacitor should be used?

I have a different application not related to I.C.E & would like to use that if it works.
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Old 31st December 2007, 09:43   #2
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Originally Posted by Ford Rocam View Post
Have seen lot of high end Audio setup's use Capacitors for their AMP's. I would like to know how it is wired in the system? .
they are wired parallel to the amps. a good thumb rule is 1F per 1000W.
however remember the devices dont do much. it is advisable to first get your wiring (Big 3) upgraded first and only then consider caps.
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Old 31st December 2007, 10:32   #3
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The idea behind caps is to have a reservoir of power for the amplifier, when peaks occur. However, if wiring of adequate rating is used (and is not coiled) then they becomes almost redundant. The level of buffer at 1F per 1000 W is more than adequate, but with proper wiring you can get away with less. Also, most amps have internal power capacitors in any case.
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Old 31st December 2007, 18:23   #4
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Quote:
Originally Posted by Ford Rocam View Post
I have a different application not related to I.C.E & would like to use that if it works.
Based on your application, perhaps more ideas could be suggested.
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Old 31st December 2007, 20:01   #5
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How much does a cap cost? I don't think i'll need a high end one. I just want to wire it parallel to the battery in my Bullet so that i could start it even if the battery drains or conks off. Old Bulls had a cap setup.
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Old 31st December 2007, 20:44   #6
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Originally Posted by Sankar View Post
How much does a cap cost? I don't think i'll need a high end one. I just want to wire it parallel to the battery in my Bullet so that i could start it even if the battery drains or conks off. Old Bulls had a cap setup.

nutcrank! we are talking of 5k caps not 5rs-50rs caps

Get a cap for your bike from Thakaraparambu shops.
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Old 31st December 2007, 21:00   #7
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nutcrank! we are talking of 5k caps not 5rs-50rs caps

Get a cap for your bike from Thakaraparambu shops.
Lol....

I know they're pretty expensive jk, but then i thought some must be there which doesn't cost 5k.. and it would be cool to have that super cool volt display when i place it somewhere visible on the bike.

Tell me which is the cheapest audio cap that i can get?
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Old 31st December 2007, 22:10   #8
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Based on your application, perhaps more ideas could be suggested.
Ok let me Explain. I don't want it for ICE setup, i have pioneer p1Y Head unit & JBL 936/636 & components in front,no subs,no amps & i am pretty happy with it. Capacitors are not for them but for other high end electronics (Standalone) which i am running in my setup. The problem i am facing now is that i am running different Engine coolant setup for my engine, whenever the Coolant Fan activates it draws huge current & the voltage drops by 1- 1.5v momentarily from stock around 14.3 & then stabilizes. but for during this few secs the engine rpm drops by few 200-300 rpm. its irritating sometime. I will be adding a few more electronic items in my setup for which i want a stable supply.
My worry is if the fan activates during boost which is likely to happen it will effect my Wideband readings, current flowing through Injectors (will effect fuel supply) & Ignition too. i want to avoid all that.
So i was just wondering if capacitor would be of any help? or should i change to a bigger battery? currently i am using Amaron Pro. my alternator is ok. Would like to experiment with Capacitor though.
Any suggestion?

Last edited by Ford Rocam : 31st December 2007 at 22:17.
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Old 1st January 2008, 09:56   #9
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Quote:
Originally Posted by Sankar View Post
How much does a cap cost? I don't think i'll need a high end one. I just want to wire it parallel to the battery in my Bullet so that i could start it even if the battery drains or conks off. Old Bulls had a cap setup.
Old Bullets never had a cap setup - they had a DC Delco (generator + ignition set; Delco = the company which used to make it - Dayton Engineering Laboratories Co., forerunner of the current Delphi Corp.) which would work without a battery. Sure, it was cylindrical like a cap, but that's where the similarity ends.

If you wire the cap in parallel to the battery, it would have discharged along with the battery!
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Old 1st January 2008, 10:13   #10
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Quote:
Originally Posted by Ford Rocam View Post
Ok let me Explain. I don't want it for ICE setup, ... my alternator is ok. Would like to experiment with Capacitor though.
Any suggestion?
This is not a situation that you should be using a capacitor. A capacitor is not a panacea for all voltage-drop ills.

Your setup is suffering from bad voltage regulation, and you have to either put in an alternator whose o/p voltage does not drop when the current demands shoot up momentarily (obviously a MUCH higher capacity alternator), or use a voltage regulator separately for supplying the sensitive electronics other than the Injection Control ECU.

Usually the injector coil current (it is quite less, really) is fed from the ECU, which regulates voltage in a narrow band, so that the injection aperture is not substantially affected by line voltage drop for whatever reason. (Otherwise, one will not be able to do dhakka-start fuel injected engines when one cell of the battery has conked off).

Nor would the spark voltage at the ignition coil.
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Old 1st January 2008, 10:14   #11
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Originally Posted by Ford Rocam View Post
So i was just wondering if capacitor would be of any help? or should i change to a bigger battery?
A bigger battery would give you more versatility, e.g. ignition, lights and audio, and would give you more value for your money. Then, when your alternator is due for replacement, you can upgrade that, too. This is the way I would go.
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Old 1st January 2008, 12:45   #12
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Quote:
Originally Posted by Ford Rocam View Post
My worry is if the fan activates during boost which is likely to happen it will effect my Wideband readings, current flowing through Injectors (will effect fuel supply) & Ignition too. i want to avoid all that.
Standalones usually have correction for injectors and ignitors control based on battery voltages. You may have to reroute your wideband power supply if the fan is casusing interference.
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Old 1st January 2008, 13:28   #13
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Adding capacitor will also remove ripples for the DC as it will stabilize the DC voltages.

But in this case I think the alternator voltage regulator is not working fine.
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Old 1st January 2008, 18:32   #14
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Originally Posted by rdkarthik View Post
Standalones usually have correction for injectors and ignitors control based on battery voltages. You may have to reroute your wideband power supply if the fan is casusing interference.
Ya i am aware. My Standalone has these features, but i would like to use this features secondary, first i would like to stabilize the supply so that there's not much drop in voltage. & set those parameters later for minor corrections.

@LBM will checkout alternator voltage regulator.

Last edited by Ford Rocam : 1st January 2008 at 18:33.
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Old 1st January 2008, 19:08   #15
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FR - Why not use a voltage stabilizer then? I have seen high end audio equipped cars use it.
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