2 diff.size cap question

[pickup1 5,000+ posts]

hey guys,i have a 1.5 farad cap now,and was thinking about getting a 1 farad also,can i use both at the same time or do they need to be both the same farad?

the 1.5 can go to my 1500d,then the 1 farad for the mid-high amp.will that work.

thanks in advance.

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[knukonceptz 10+ year member]

You can use them both at the same time

 

[fatboy 10+ year member]

get a new alt not more caps

 

[Johnny Drama 5,000+ posts]

hey guys,i have a 1.5 farad cap now,and was thinking about getting a 1 farad also,can i use both at the same time or do they need to be both the same farad?the 1.5 can go to my 1500d,then the 1 farad for the mid-high amp.will that work.

thanks in advance.

Are you having voltage problems? What vehicle?

A cap is only a bandade for the problem. Your car runs off its alternator when running. If your alternator is having issues charging and maintaining your voltage with your stereo on a cap will do nothing more then drain more off the already failing alternator.

That being said...If you are experiencing this problem and dont have the money to fully upgrade your electrical system, try adding a dedicated battery for the stereo with a battery isolator so that you have no issues starting you car if the stereo battery dies.

If you have no voltage drop problem or the problem is minimum, why spend the money on something that isnt going to help you?

 

[knukonceptz 10+ year member]

a cap will do nothing more then drain more off the already failing alternator.

I see that statement all the time - but a Cap is a storage device - it does not consume power - it holds what is on hand. Having 1 or 2F will hardly be a strain on any cars charging system compared to the huge draw the amp's consume. A cap has a very low resistance. ESR of .001xx in most cases- which is less resistive then some folks grounds. So very little voltage is lost when it is charged/discharged, so how can something that does not consume and does not waste power be a strain?

Every amplifier has some level of capacitance built in, this is to smooth out the spikes the power supply "sees" You will note they have many small caps in an amplifier due to the low ESR they offer, using many smaller caps is better then one large cap. Adding a single 1F cap close to an amp will help reduce additional spikes and could result in a more effcient (ie cooler running) and cleaner output from an amp.

Caps are not the "solve all" device some make them to be, but they certainly are NOT straining a charging system. In fact your isolator theory will cause more strain then the two caps would.

That being said...If you are experiencing this problem and dont have the money to fully upgrade your electrical system, try adding a dedicated battery for the stereo with a battery isolator so that you have no issues starting you car if the stereo battery dies.

The Isolator is electronic, it takes power to operate (about 0.3v-0.5v from the ALT input) So now he has less voltage to both batteries. Adding a second battery by itself would be the best option over a cap or Isolator. Just be sure to fuse both sides of the power wire with your second battery.

In my first post I thought you owned both caps aleady, use the money towards a good second battery instead

 

[Johnny Drama 5,000+ posts]

I see that statement all the time - but a Cap is a storage device - it does not consume power - it holds what is on hand. Having 1 or 2F will hardly be a strain on any cars charging system compared to the huge draw the amp's consume. A cap has a very low resistance. ESR of .001xx in most cases- which is less resistive then some folks grounds. So very little voltage is lost when it is charged/discharged, so how can something that does not consume and does not waste power be a strain?

It may store power, but when the electrical system cant supply the demand the cap will put out its stored energy, and since its very minimal amount the cap will constantly need charging. Causing a drain on the system however minimal you want to look at it. Therefor IMO, it is worthless to have.

Every amplifier has some level of capacitance built in, this is to smooth out the spikes the power supply "sees" You will note they have many small caps in an amplifier due to the low ESR they offer, using many smaller caps is better then one large cap. Adding a single 1F cap close to an amp will help reduce additional spikes and could result in a more effcient (ie cooler running) and cleaner output from an amp.
Caps are not the "solve all" device some make them to be, but they certainly are NOT straining a charging system. In fact your isolator theory will cause more strain then the two caps would.

From what I have found personally testing, the isolator will keep your starting battery from draining to the point of failure. On the otherhand while running your car will run off its alternator. Adding the isolator will drain a little more off your alternator, and may cause the alt to fail. The up hand is that you atleast know your car will start and continue until you can afford the upgraded alternator.

The Isolator is electronic, it takes power to operate (about 0.3v-0.5v from the ALT input) So now he has less voltage to both batteries. Adding a second battery by itself would be the best option over a cap or Isolator. Just be sure to fuse both sides of the power wire with your second battery.
In my first post I thought you owned both caps aleady, use the money towards a good second battery instead

Nothing really to add here. In another thread you talked about NOT to do this...

I would think that they minimal loss of .5v would be better for the assurance that your car will continue to operate (*as lond as you do not totally exceed the alternators reserve output for extended periods.)

 

[Johnny Drama 5,000+ posts]

Nothing really to add here. In another thread you talked about NOT to do this...I would think that they minimal loss of .5v would be better for the assurance that your car will continue to operate (*as lond as you do not totally exceed the alternators reserve output for extended periods.)

Before you add your long reply, I re-read the other thread. I read it wrong the first time.

You can disreguard that comment.

 

[knukonceptz 10+ year member]

It may store power, but when the electrical system cant supply the demand the cap will put out its stored energy, and since its very minimal amount the cap will constantly need charging. Causing a drain on the system however minimal you want to look at it. Therefor IMO, it is worthless to have.

How long do you think it takes to charge a cap when inline in a system like a car? Electricity moves at speed of light, your music moves at oh say speed of sound....which do you think can react faster to the music? Unless your are doing stright sweeps a 1F cap will recharge between beats.

From what I have found personally testing, the isolator will keep your starting battery from draining to the point of failure. On the otherhand while running your car will run off its alternator. Adding the isolator will drain a little more off your alternator, and may cause the alt to fail. The up hand is that you atleast know your car will start and continue until you can afford the upgraded alternator.

An Isolator does what it says. It isolates Battery A and Battery B (in rear) from each other with the ALT powering both. With the car on, both are equal. Car off Batt A has no draw (other then standard car acc). Batt B is powering your stereo's amps in the rear and being drained while you sit car off and music on (note your HU may be powered still off Batt A if you do not wire it to Batt B and still causing a small draw)

Now when you start your car and Batt B is very low, Batt A will start the car, but the ALT will not be happy with Batt B being low and will need to work extra to get that one up and maintain Batt A as well.

Running with out the isolator, both Batt A and B would be connected and allow for double the extended play time (assuming they are equal size) and upon start up after the above condition, the ALT sees only one load and it would not need to work as hard as the two batteries combined are not as "dead" as the Batt B alone would have been.

Can you drain your batteries with the car off without an isolator - Yes, you can. But with double the reserve you have double the length before this happens. Buy a third battery instead of the Isolator and you have extended your time even longer. Use a voltmeter to monitor your electrical system and you wont need the Isolator to protect you against a dead battery. I guess you could say the isolator just "idiot proofs" the whole thing.

If your ALT fails, your running on battery only and that will not last you very long. Certainly not long enough to to save for a HO Alt (unless you make a few hundred $ a day )

Nothing really to add here. In another thread you talked about NOT to do this...

I am confused, I have always been Pro- Battery and against Isolators, and some what in favor of caps - this of course in audio related topics.

I would think that they minimal loss of .5v would be better for the assurance that your car will continue to operate (*as lond as you do not totally exceed the alternators reserve output for extended periods.)

.5v is minimal but an ESR of .001 is a strain? //content.invisioncic.com/y282845/emoticons/crazy.gif.c13912c32de98515d3142759a824dae7.gif Most battery specs are based on 10.5V is a dead battery. Removing .5V from a 14.4V system is 1/8th of the usable voltage (14.4-10.5 = 3.9; 0.5V is 1/8 of 3.9V)

 

[knukonceptz 10+ year member]

Before you add your long reply, I re-read the other thread. I read it wrong the first time.You can disreguard that comment.

LOL, I was wondering what you had meant by that: //content.invisioncic.com/y282845/emoticons/biggrin.gif.d71a5d36fcbab170f2364c9f2e3946cb.gif

 

[Johnny Drama 5,000+ posts]

How long do you think it takes to charge a cap when inline in a system like a car? Electricity moves at speed of light, your music moves at oh say speed of sound....which do you think can react faster to the music? Unless your are doing stright sweeps a 1F cap will recharge between beats.



An Isolator does what it says. It isolates Battery A and Battery B (in rear) from each other with the ALT powering both. With the car on, both are equal. Car off Batt A has no draw (other then standard car acc). Batt B is powering your stereo's amps in the rear and being drained while you sit car off and music on (note your HU may be powered still off Batt A if you do not wire it to Batt B and still causing a small draw)

Now when you start your car and Batt B is very low, Batt A will start the car, but the ALT will not be happy with Batt B being low and will need to work extra to get that one up and maintain Batt A as well.

Running with out the isolator, both Batt A and B would be connected and allow for double the extended play time (assuming they are equal size) and upon start up after the above condition, the ALT sees only one load and it would not need to work as hard as the two batteries combined are not as "dead" as the Batt B alone would have been.

Can you drain your batteries with the car off without an isolator - Yes, you can. But with double the reserve you have double the length before this happens. Buy a third battery instead of the Isolator and you have extended your time even longer. Use a voltmeter to monitor your electrical system and you wont need the Isolator to protect you against a dead battery. I guess you could say the isolator just "idiot proofs" the whole thing.

If your ALT fails, your running on battery only and that will not last you very long. Certainly not long enough to to save for a HO Alt (unless you make a few hundred $ a day )

I am confused, I have always been Pro- Battery and against Isolators, and some what in favor of caps - this of course in audio related topics.

.5v is minimal but an ESR of .001 is a strain? //content.invisioncic.com/y282845/emoticons/crazy.gif.c13912c32de98515d3142759a824dae7.gif Most battery specs are based on 10.5V is a dead battery. Removing .5V from a 14.4V system is 1/8th of the usable voltage (14.4-10.5 = 3.9; 0.5V is 1/8 of 3.9V)

Interresting info.

 

[pickup1 5,000+ posts]

thanks for the replies,the issue isnt voltage drops,its my wallet and space in my pathfinder.

got a big house payment,3 kids and a limited budget!!

i have 4 gauge running to the back now and was wanted to keep as much voltage back there as possible,without have to upgrade the batt.,alt.,....1/0 wire!

space is limited,plus i really didnt want to run another battery,so i though if i added another cap,it would help out.i always use bigger amps and thought this would help.it sure wouldnt hurt,would it?