Bavarian Soundwerks
Page 1 of 3 123 LastLast
Results 1 to 25 of 54

Thread: Lights Dim when Bumping My Subs Do I need A Capacitor?

  1. #1
    Join Date
    Oct 2002
    Location
    SoCal
    Posts
    1,801
    My Cars
    ///M3

    Lights Dim when Bumping My Subs Do I need A Capacitor?

    I have two 12" Image Dynamics IDQ powered by MTX 81000d amp with 1 gauge wire. My interior lights and tail lights dim when the subs hit. But my hids dont dim at all. Im running the power wires directly from the battery both positive and negative ... because im thinking if i ground it on the chassis i will get some chassis noise when i close the doors.

    Do i need a capacitor? If so what brand and model? I dont want to spend too much but please tell me if i should pros and cons.

    TIA

  2. #2
    Join Date
    Apr 2004
    Location
    UK
    Posts
    15
    My Cars
    BMW E65 730d Sport '06
    A cap may help, but Id probably go for a split charge system. This will give you a battery in the trunk, specially designed for your audio system.

  3. #3
    Join Date
    Oct 2002
    Location
    SoCal
    Posts
    1,801
    My Cars
    ///M3
    I maybe unfamiliar with UK cars... but our e36s have the battery in the trunk already? by split charge system you mean... two batteries correct? This is what i found online. It seems complicated.

    http://www.talkaudio.co.uk/photopost....php?photo=816

  4. #4
    Join Date
    Jul 2004
    Location
    Austin, TX
    Posts
    1,192
    My Cars
    AA turbo 332i
    Quote Originally Posted by DFH
    A cap may help, but Id probably go for a split charge system. This will give you a battery in the trunk, specially designed for your audio system.
    wow, i dream of such things!! i have a hooker cap (not sure of the model, it was bought used and is about 10" long) and my headlights still dim occaisionally when the bass hits certain notes, usually making the cd skip as well. a cap defintaly will help with your power issues, before i had mine the guages and obc would also dim, and that's kinda scary.

    1995 325i | OBD1 S52 | S50 cams | AA Turbo TD06 20g / 42lb / Porsche maf | .140 MLS | F1 s3 clutch | Ultimate SSK | AKG 75D subframe/diff bushings | 3.23 LSD | Powerflex LCAB/RTAB | e46 fca | Raceland coils | BMP rear arms | DEPO HID | AEM Failsafe | Aeromotive FPR | Walbo 255 | 3" Magnaflow muffler/cat/res | 17x8.5/9.5" 225/45 & 255/40

  5. #5
    Join Date
    Oct 2002
    Location
    SoCal
    Posts
    1,801
    My Cars
    ///M3
    All my interior lights dim... guage, obc, dome, + taillights. So your saying the Cap didnt solve your problems just helped?

  6. #6
    Join Date
    Jan 2004
    Location
    Aston, PA
    Posts
    3,073
    My Cars
    95' 325i 2.8l
    Yeah exactly
    Caps are very overrated. They will not Fix your problem, but will decrease the dimming a bit.

    I think your best option is to upgrade your battery/alternator. You may also wish to run a second battery

  7. #7
    Join Date
    Jul 2004
    Location
    Austin, TX
    Posts
    1,192
    My Cars
    AA turbo 332i
    helped, yes, but i have to seriously rock to see the lights dim. i even have an optima yellow top gel-cell battery, with 1600 total watts in my stereo. only the headlights still dim, but only when it's like cranked so loud that i start to worry about speakers blowing...

    1995 325i | OBD1 S52 | S50 cams | AA Turbo TD06 20g / 42lb / Porsche maf | .140 MLS | F1 s3 clutch | Ultimate SSK | AKG 75D subframe/diff bushings | 3.23 LSD | Powerflex LCAB/RTAB | e46 fca | Raceland coils | BMP rear arms | DEPO HID | AEM Failsafe | Aeromotive FPR | Walbo 255 | 3" Magnaflow muffler/cat/res | 17x8.5/9.5" 225/45 & 255/40

  8. #8
    Join Date
    May 2004
    Location
    Florida
    Posts
    1,977
    My Cars
    F15, F31
    yes, you got to install a cap, and groud it no further than the amp, and not more than 1ft. but dont ground it at the battery, man . no need for new alternators.

  9. #9
    Join Date
    Oct 2003
    Location
    Los Gatos
    Posts
    2,245
    My Cars
    1999 Estoril Blue M3 Convertible
    a cap is a bandaid. the only thing that will increase capacity is an upgraded alternator.
    but caps are cheap, might as well try it first, but don't expect miracles.
    1999 Estoril Blue M3 Convertible
    1997 TL1000S (Daily road, track, touring bike)
    2002 KTM 300MXC (Enduro racer)

    GOD - An imaginary friend for Grownups.

  10. #10
    Join Date
    Dec 2002
    Location
    Houston, Tx
    Posts
    625
    Exactly, a cap can only charge so quick and a second 1 farad can only do so much also. But still slower than an alternator, the weakest link in your chain right now....the caps can only stabilize as much current as the alternator is putting out. That is what will prevent the dim, is a true high output alternator.
    2003 M3 Cabrio Carbonschwarz SMGII

    Boston Acoustics
    SPG555
    GT-28

  11. #11
    Join Date
    May 2004
    Location
    Florida
    Posts
    1,977
    My Cars
    F15, F31
    WHAT???

    current from alternator has got to travel long way as opposed to the capacitor wired very close to the amp. Caps are a MUST. not only they provide you with quick, short bursts of energy when your subs hit hard, but also protect your car's electrical system against current fluctuations.

    before you upgrade your alternator, install second battery etc., INSTALL A CAP!

    as I said before, don't ground audio system at the battery. this is where I see your problem might be (of course after you install that cap that is a must)

    good luck!

  12. #12
    Join Date
    Oct 2003
    Location
    Los Gatos
    Posts
    2,245
    My Cars
    1999 Estoril Blue M3 Convertible
    sure, they store energy and release it quickly.

    but all the energy comes from one place, the alternator. Sure, a cap will smooth things out a bit and provide a bit of dynamic headroom, but they don't 'produce' power, only handle how it's given out.

    cap a must?

    no
    1999 Estoril Blue M3 Convertible
    1997 TL1000S (Daily road, track, touring bike)
    2002 KTM 300MXC (Enduro racer)

    GOD - An imaginary friend for Grownups.

  13. #13
    Join Date
    Jul 2004
    Location
    Austin, TX
    Posts
    1,192
    My Cars
    AA turbo 332i
    a cap is a lot cheaper than a dual battery system or a souped-up alternator....go for the cap first!

    besides, his battery is in the trunk, so he shouldn't have a super long hot wire or anything crazy like that. btw, how many total watts/amps are you running, and do you have a distribution block if you do have multiple amps?

    these would also be factors to condsider.

    1995 325i | OBD1 S52 | S50 cams | AA Turbo TD06 20g / 42lb / Porsche maf | .140 MLS | F1 s3 clutch | Ultimate SSK | AKG 75D subframe/diff bushings | 3.23 LSD | Powerflex LCAB/RTAB | e46 fca | Raceland coils | BMP rear arms | DEPO HID | AEM Failsafe | Aeromotive FPR | Walbo 255 | 3" Magnaflow muffler/cat/res | 17x8.5/9.5" 225/45 & 255/40

  14. #14
    Join Date
    Aug 2004
    Location
    Canada
    Posts
    726
    My Cars
    325iS
    Alternator is your solution. If you want a quick fix, try a cap.

  15. #15
    Join Date
    Jan 2003
    Location
    San Francisco
    Posts
    3,316
    My Cars
    99' Cosmos ///M3
    Quote Originally Posted by PENER
    WHAT???

    current from alternator has got to travel long way as opposed to the capacitor wired very close to the amp. Caps are a MUST. not only they provide you with quick, short bursts of energy when your subs hit hard, but also protect your car's electrical system against current fluctuations.

    before you upgrade your alternator, install second battery etc., INSTALL A CAP!

    as I said before, don't ground audio system at the battery. this is where I see your problem might be (of course after you install that cap that is a must)

    good luck!
    u must work at an audio store.
    to the thread starter, do not listen to this guy. a capacitor acts as a bandaid for a system. It stores power, and releases it as needed. Sorta like a battery, they both work off the alternator, which is the SOURCE of power. The reason the lights dim is because of the drop in voltage, or an easier way to understand would be that the alternator cannot keep up with the current that the amplifier is drawing, therefore the lights dim. Installing a capacitor like i said before draws power from the alternator, now the problem is the capacitor wont stay charged, but will be drained, only causing it to put an extra load on the alternator, as it just keeps sucking power from the alternator to try to provide the current. Adding a capacitor is fine to use when the source of power is sufficient in powering everything. Adding a second battery isnt necessary either, u can replace the battery if u want with a red/yellow top of another kind of deep cycle battery, but alternator is the real source of the problem.
    How is ur amplifier tuned? what is the low pass set at, what is the gain set at, and if u are using bass boost, turn that ish down all the way.

  16. #16
    Join Date
    Oct 2004
    Location
    NEW YORK
    Posts
    148
    My Cars
    1997 540i
    I had that problem for years with different cars. Then I added caps. Now I added a Lighting Audio battery. I have 2 Kicker L7 Subs, interiors, 2 orion amps, 2 pairs of HID's ( Headlights and Fogs).
    No more blinking lights until.

  17. #17
    Join Date
    Oct 2002
    Location
    SoCal
    Posts
    1,801
    My Cars
    ///M3
    my friend sent me a link from sound domain saying i should up grade the big 3. upgrade ground wire from batt - to chassis, batt + to alternator, and alternator to chassis. I think imma try this first anyone else tried this?

  18. #18
    Join Date
    Sep 2004
    Location
    Syracuse, Ny
    Posts
    286
    My Cars
    95' 325is
    Thats good practice. It helps improve the flow of the electrical system. Never hurts. Will it solve your problem.....almost positive no. So what about a capacitor? Will this solve your problem? Possibly, possibly not. read on for explanation.

    heres an explanation of why. Your alternator makes electricity. It makes it at 12V and it makes a certain number of amps (say 90). To calculate power (which is measured in watts) you multiply voltage times amperage (VxA=W). all of your electrical systems stock use less than what your alternator makes, say 75 amps. this means that none of your electrical systems ever overwhelm your alternator and theres plenty of power to go around. When you added your amplifier you probably installed a fuse. That fuse is an approximation of the maximum draw of the amp (for a 1500W system the fuse will most likely be about 110A(supposedly 125 amps by calc)). What has now happened is that you have added a 110A accesory onto your engines electrical system. So that 90 that it used to make now isnt enough.
    75 car Amps + 110 stereo amps = 185 total amps
    90 alternator amps - 185 total amps = -95 amps
    Now you amplifier does not always demand 110 Amps in fact it probably only normally requires about ~50-60 amps. while this still taxes your alternator it can work a little overtime (thereby shortening its lifespan) to make those extra 35-45 amps. what it cant do though is instantaneously make 85-95 amps which is what the amplifier draws when it makes really loud notes(bass turned up). So what the amplifier does becuase its powerful and sucks the power out of the system is robs the normal stuff of its power (dimming lights, slowing spark, etc, etc.). so why all this explanation.
    what a capacitor does (slang is cap), is provide a resivoir of electricity. It does this by constantly charging off the alternator. So the alternator makes its absolute maximum charge all the time (lets say 140 amps working full overtime aka very shortened lifespan) charging the capacitor and running the electrical system. BUT when the amplifier requires its full 110 amps instead of draining the electrical system it drains the capacitor. which means no dimming. but then the alternator has to charge it back up again.

    SO...without the explanation...
    if you get a big enough alternator to run the electrical system and all your aftermarket then you wont have the problem anymore (no BMW alternators can do this(biggest is 140 amps unless i missed something (very possible)), your talking a likely 180~200+ amps with your setup) if you just get a cap and the alternator cant charge it fast enough it wont be 100% effective either. To do it RIGHT you get both. The cap and the alternator. the cap to give the amp those times of really high demand and the alternator to enable the effective running of the lectrical system without overtaxing the alternator. you can get aftermarket alternators most likely, and you can get them rewound to make more power too, this will be something i will look into in the future but havent fully researched yet (know the concept just not the model numbers and cost). So there ya go. good luck.

  19. #19
    Join Date
    May 2001
    Location
    Easley, SC
    Posts
    11,931
    My Cars
    2017 530i M-sport
    CrayzeeM3-

    Your factory alternator is 80a. Upgrade to the 140a version. Problem solved. It solved my problem with dimming. If you decide to do this, try to find an alternative to going through BMW. They're spendy.

    As has been said, a cap is a bandaid approach. Might help, might not. The fact is your charging system is not making enough power to handle the current draw of your accesories and audio system.

    TheMuchacho-

    Don't bash those of us who work in the business just because we work in the business. We just might know a little more than you do. There are plenty of guys, both in and out of the business, that don't know what they're talking about and/or blow smoke.

    Jay

    From wannabe to has been in a few short years..... the older I get, the faster I was

  20. #20
    Join Date
    Oct 2004
    Location
    Los Angeles, CA
    Posts
    903
    My Cars
    Various Prototype BMW's

    forgot something

    Luni2nz: I'm with you! We do know a thing or two, right?
    A Cap is a bandaid, yes, but for most setups, it helps out enough. All of the above posts are correct, especially gbear14275. I would always recommend a cap in any high powered system, as it does increase the immediate voltage provided to the amplifiers. If the amplifier has an unregulated power supply, this can make an audible difference.
    But yes, an alternator is the only "true" fix.
    Jason Seaver | Founding Partner | Product Engineer
    e: jws@bavsound.com
    Bavsound | Audio Solutions Engineered Specifically For Your BMW
    www.bavsound.com | 404.381.1800

  21. #21
    Join Date
    May 2004
    Location
    Florida
    Posts
    1,977
    My Cars
    F15, F31
    just to begin with, I am not working in any store. my knowledge is based on what I've read, not what I heard from someone. I don't know everything, fact, but I'm sure of the things I'm talking about. there is a lot bullshit here so let try again sort it out a bit.


    before your audio install gets so advanced that it requires better alternator, you will probably already have 2 big capacitors installed. adding capacitor to the system is the next LOGICAL step for this guy. I'm not 100% sure it will solve his problem, but it's not money waste anyway. he will need that cap with or w/o new alternator.

    next, contrary to what someone here suggested, cap will not make alternator work to the max. before you install the cap, you have to charge it, so it is like an exta battery, before you take it out and put it into the box you have to discharge it. cap draws current only when it discharges a bit when giving out power for hard hitting subs. the easiest way to understand it is to look at the digital meter on top of the cap.

    I'm afraid a lot of confusion here comes from not understanding the difference between constant power draw of the amp (imagine loud playing mids and highs) and spikes in power need when the subs are hitting hard. Of course if your constant power needs are greater than what your alternator can put out after supplying car's electrical system, then you need that better alternator. but you try to fix the other problem (sudden power drops for bass) by adding caps first. and you better add that cap, so your car is not getting confused wtf is going on with the electrical system when you crank up the volume.

    BTW, I would like to know how many of you here that say he's got to get better alternator have got one installed in their own car. and out of you that do have one, how many are still running w/o cap in the system?


    I had that problem for years with different cars. Then I added caps. Now I added a Lighting Audio battery. I have 2 Kicker L7 Subs, interiors, 2 orion amps, 2 pairs of HID's ( Headlights and Fogs).
    No more blinking lights until.
    here is the perfect example. no new alternator. just added caps, battery, problem solved. new battery worked in this case, however we dont know how was it after caps and before new battery was installed. the general rule for extra battery is that you need one if you intend to play audio with the engine turned off (but that's just in general). on the other hand caps are like a little batteries for your audio but way faster. so more or bigger caps could have worked here too.

    after all it's your money. you may listen to someone teling you to spend $100 on capacitor (a must in decent audio install) or listen to someone saying go ahead and invest few times as much. then you should buy that cup anyway, so my question is why not doing it in the first place and see what happens.

    another thing here is why none of the experts brought up grounding to the battery thing. I am not going to elaborate on this as I'm not 100% sure about it, but he should not ground to the battery.

    my advice is: invest in the capacitor and don't ground anything to the battery. see what happens. if it helps, great, if not, money is not wasted on good cap (at least the first one in your audio system). good luck and keep us updated

  22. #22
    Join Date
    Sep 2004
    Location
    Burbs of Chicago
    Posts
    102
    My Cars
    93 325is
    try a batcap, you can get them pretty cheap on eBay. They are part battery part capacitor.

  23. #23
    Join Date
    Jan 2003
    Location
    San Francisco
    Posts
    3,316
    My Cars
    99' Cosmos ///M3
    Quote Originally Posted by PENER
    just to begin with, I am not working in any store. my knowledge is based on what I've read, not what I heard from someone.
    whats teh difference.....

    Quote Originally Posted by PENER
    I don't know everything, fact, but I'm sure of the things I'm talking about. there is a lot bullshit here so let try again sort it out a bit.
    the only BS here is the fact that u said he MUST have a cap.

    Quote Originally Posted by PENER
    before your audio install gets so advanced that it requires better alternator, you will probably already have 2 big capacitors installed.
    ?????????

    Quote Originally Posted by PENER
    adding capacitor to the system is the next LOGICAL step for this guy. I'm not 100% sure it will solve his problem, but it's not money waste anyway. he will need that cap with or w/o new alternator.
    how do u know its not a waste of money? i personally bought two 1farad LA caps just to test the theory that they are useless on a weak electrical system. sure enough when i addded two of them on my JBL 1200.1 there was no help at all.

    Quote Originally Posted by PENER
    next, contrary to what someone here suggested, cap will not make alternator work to the max. before you install the cap, you have to charge it, so it is like an exta battery, before you take it out and put it into the box you have to discharge it. cap draws current only when it discharges a bit when giving out power for hard hitting subs.
    unfortunately the capacitor does get drained of power, this is what causes it to draw current and put an extra load on the alternator, no one said it makes the alt. work to the max, it simply just puts an extra load on it.


    capcacitors may or may not work, it all depends on the eletrical system and waht kinda of current is getting drawn by the amplifiers and other eletrical parts in the car. if the source of power is strong and sufficient enough for everything, then sure a capacitor wouldnt hurt, but adding a cap is a short term solution but will just put an extra load on it defeating the purpose of getting one, which is to support the electrical system in supplying power for everything.

  24. #24
    Join Date
    Jan 2003
    Location
    San Francisco
    Posts
    3,316
    My Cars
    99' Cosmos ///M3
    Quote Originally Posted by LUNI2NZ
    TheMuchacho-

    Don't bash those of us who work in the business just because we work in the business. We just might know a little more than you do. There are plenty of guys, both in and out of the business, that don't know what they're talking about and/or blow smoke.

    Jay
    no offense meant towards u or anyone working in a car audio store. i myself may even be working at curcuit city soon

  25. #25
    Join Date
    Dec 2002
    Location
    Houston, Tx
    Posts
    625
    Everyone should just go out and upgrade their alternator to the High Output Bosch like me. A second battery is controlled most likely by a simple isolator that determines when the second battery needs to come into play. But if your system is just bumping a straight 2 hours then it all comes down the alternator. In turn, you're just hurting everything else electrical in your car. How about you upgrade the alternator and solve all your problems like me. No added battery, takes up room anyways.

    A capcitor is just like a battery, the difference in the way it is built. The caps you have for cars are huge parallell plate caps, your battery does the similar in having a medium between each charged side. Caps charge and dishcarge quick, batteries slower. If played loud both will still be able to discharge in turn leaving a low current and voltage for your amps. So the more caps batteries, the longer it takes to drain, depending if you're playing Lil Jon or classical. Even though your lights may not dim, your amps are playing less power due to the loss of voltage if your alternator can not supply enough current....like I said earlier and no one listens, it is the weakest link in the chain.

    If you have a water tank(battery or capacitor) with water and you puncture the bottom to let out 1 gallon of water per minute(music/power) and at the same time pour in half a gallon per minute(alternator chargin), you're eventually going to drain the tank empty. Do yourself a favor and pour more water in(upgrade alternator).
    2003 M3 Cabrio Carbonschwarz SMGII

    Boston Acoustics
    SPG555
    GT-28

Page 1 of 3 123 LastLast

Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •