Thread: Finding +and- on a cap

Originally Posted by Sabrewings

Second battery is worthless too. Batteries are 12v. Usually the car's electrical system is above that. So, the battery won't do anything until the alternator is strained and the system's voltage drops to 12v. Then the batteries will keep it from dropping any lower until they are dead. Only problem is that when the load lifts now the batteries are drawing current as they try to recharge.

The only real answer to the problem is a better alternator.

all i have to say is DAMN your a dumb ass. adding a second battery will give him more reserve. a battery with a CCA rating of 600amps is like adding a 100 farad capacitor. what you are saying is that the battery in the front of every vehicle serves no purpose then.

Originally Posted by _nick_

batcaps are a good choice....A capacitor serves as a very good buffer for those sudden voltage drops hon hard bass notes. Its not the fact that your car doesnt have enough power for your system, its the fact your alternator has a 'lag' time in delivering the voltage so suddenly, so the alternative is to fall back on your battery, which runs at a lower voltage than your alternator, so you get the ligh dimming with the fluctuating voltage. (remember, your battery has a HUGE amount of current to deliver, but at a lower voltage than your alternator so you get the light dimming) A cap buffers this out by storing a large amount of energy at the alternators voltage, and discharging and recharging it very quickly iliminating the need to fall abck on your batteries current. Wise installers always say "the battery is to start your car and use electronics/lights with the car turned OFF..once your car is running it should serve NO purpose"

by you theory a cap will solve all light dimming problems. i have been a installer of car audio for well over 10 years now. in my wife's car she has a 600 watt sound system. by your theory, if i installed a 1 farad cap i would not have any dimming. because i would have 600micofarads for the system and a "extra" 400microfarads to use. WRONG. i did this at my former employer to prove to my boss caps are worthless. i charged the cap properly and then played a song at full tilt. my lights dimmed horribly a little worse thatn without the cap actually. i then installed a kinetik hc600 battery. which has more power than a 100 farad cap. i had no dimming lights at all.

Sabrewings, you are dead on.

Reinke: If you want to add more batteries go ahead. all we are saying is they run at a lower voltage than your electrical system, and put an enormous load on your alternator when you start adding additional batteries. Not to mention they are like dead-weight (50 pounds easy), they are not the answer for minor voltage drops in a moderate system, capacitors are used in all electronics (even in many cars alternators) to buffer out those brief and sudden voltage fluctuations. .. caps are not a solution to make more power, but when the power doesn't come quick enough capacitors fill the gap to avoid sudden voltage drop. Your free to add all the batteries you want, but that is not the way i was trained in mobile electronics, and from personal experience i would never add an additional battery to a regular system before an alternator upgrade (im not gonna call you a dumb ass, that would be pretty much un-called for )

well we all hove our opinions. i has doped up on my meds last night sorry for calling you a dumb ass. but, car audio capacitors and the ones used inside of amps and for alternators are completely different. alot of times people run a cap that is way too small for there needs. the rule of thumb is that for every 500 watts of power you must have 500microfarads. for my competition truck i have a little over 10,000 watts on tap. i would need 10,000 microfarads of capacitience. which would completely take up my entire bed and then some more room. i added 5 kinetik hc2400 batteries. at that point i would recommend a high output alt or 2. i have 2 300amp alt in my truck and they keep up perfectly. i even have about 100 amps on reserve to help with the auxillary lights other accersories. when the average persone adds a single aux. battery a high output alternator is not needed. i took the MECP advanced courses for my old jod in florida, i also took a a electronic repair course, and a electrictions course to become a contractor. i know what i am talking about just like the fellow Airman does. there are dead weight some like my batteries weight almost 100lbs. but, in the long run a extra battery will have no negative effects on a cars stock alternator, and it will be alot safe to run that a capacitior.

actualls a microfarad it used to measure any capacitor. go to walmart and look at there amp kist that comes with a cap. it says 500 microfarads.

i dont know about microfarads but i always thought caps were sold in .5 farad or 1 farad increments (.5's are small caps)

reinke LOL at your drugged up comment im guilty of that myself...after a night of drinkin or whatever come home hit the forums and start flaming people haha...the world of internet hatin' its a victim-less crime!

In a small to moderate system caps absolutely do help, they are essentially batteries but they charge up and discharge MUCH faster than a battery and will hold a voltage equivalent to your charging system (not 12V like batteries)...if your into competition and you need a HUGE amount if current for a relatively short amount of time (about 1 minute) than multiple batteries will provide that to you. Sometimes batteries can appear they are helping, but you soon find out they are not helping when your alternator burns out on you way sooner than in should...

Sabrewings i guess you are right because i just typed in the simple term "500 microfarads to farads" in google search and google calculator gave me the result of "500 microfarads = 0.0005 farads"

try the link for yourself;
500 microfarads to farad - Google Search

Originally Posted by JoshMcMadMac

Please do not ever do that. It used to be the case with older cars that you could start the car, then pull the battery. That is no longer so, and pulling the battery with the car running can create a bad situation for a lot of the electronics in a modern vehicle.

i did it just yesterday...car ran for 5 minutes with no battery until i switched it out. Ran just fine no problems to report....

cant see how it would spike the voltage when a battery runs at a lower voltage than your charging system. There was actually a TSB for my old car that required disconnecting the battery while the engine is running to diagnose it.