Capacitors,capacitors......
Printed From: the12volt.com
Forum Name: Car Audio
Forum Discription: Car Stereos, Amplifiers, Crossovers, Processors, Speakers, Subwoofers, etc.
URL: https://www.the12volt.com/installbay/forum_posts.asp?tid=8043
Printed Date: May 10, 2025 at 9:30 AM
Topic: Capacitors,capacitors......
Posted By: Dan M C
Subject: Capacitors,capacitors......
Date Posted: January 12, 2003 at 5:35 PM
Can a cap save the alternator ?,another question...my car's alternator puts out 80 amps,now my system is kinda big (4 amplifiers,etc) and how do i find out what my reserve amperage is,i doubt it i have any left...my amps are like this: #1-360 Watts mono for my sub #2-2x100 Watts for one of my mids set #3-2x50 Watts for another set of mids #4-2x50 Watts for a set of tweeters I do have 2 caps right now,one 1 Farad and another 1/2 Farad,is it enough ? and is my alternator gonna meet it's maker ?,hopefully not And thank you  ------------- Dan M C
Replies:
Posted By: pain_is_lov3
Date Posted: January 12, 2003 at 8:07 PM
More than likely your alternator will meets its maker quicker than normal, heh. But to figure out your reserve power take your alternators amp rating and mulyiply it by 40% (0.4)This will give u an idea of ur reserve capacity so your reserve is.... 32 amps. So by looking at your power draw u are prolly well over your reserve capacity. About the cap saving your alternator, no it prolly won't. So insead of spending all that money on caps u should have spent it on a bigger alternator. I did the same and my alternator pooped out on me so i had to go buy a new one for my honda. I got a 130 amp one now and that should be good for u cuz i had almost the same set up.
Posted By: Dan M C
Date Posted: January 12, 2003 at 9:29 PM
 I checked and the alternator on my BMW is rated at 80 Amps,i found somewhere a formula that (crutchfield,"the installation doctor") helped me figure out the exact figure of 32 Amps i have in rezerve....but i need 35 Amps (140A : 4=35 A), does that mean that "maybe,just maybe" i can get by providing i don't play my stereo to 3/4 volume ?,i don't even know if there is a way to get a higher amperage alternator for my BMW,i think even 100 A would do,can my old alternator be rewired to put out more ?
Thank you and i apreciate it ------------- Dan M C
Posted By: Derrik
Date Posted: January 13, 2003 at 12:30 AM
I hate to tell you this but putting more caps on your system will kill your alternator faster. Get a secondary alternator, or a second battery, or get a bigger alternator. Now think about this for a sec. The alternator is your power source. by having more caps just like having storage of power for you, but how much storage do you get? Now once the caps discharged, your alternator not only has to work hard to keep up with your system, it has to recharge the caps. Caps are good for voltage regulators though. With all the caps you're spending on. Best just to get a bigger alternator or get a secondary...
Posted By: pain_is_lov3
Date Posted: January 13, 2003 at 10:37 AM
Yes your alternator can be rebuilt to put out more amps and its cheaper than buying a new one. So u decide what ya wanna do. Both will do well with your power demands
Posted By: Dan M C
Date Posted: January 13, 2003 at 11:59 AM
 Thank you all  ------------- Dan M C
Posted By: CharlzO
Date Posted: January 18, 2003 at 4:29 PM
Once again, I'll put in my two cents, not that I'm trying to stir up anything, just my doings. I've run a pair of 1 Farad caps behind my A1300HC, and A2150 HCX off a stock 60 Amp alt for a few years, and not even a hiccup in it. Just my two cents.
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