Capacitors? Where's the proof?

[audioholic 5,000+ posts]

just wow, this thread is a minefield. I feel sorry for anyone reading this thread that truly does NOT understand how caps work. I guess ca.com hasn't changed much over the years

Every forum has people who give misinformation without realizing it. If a person is too inexperienced to see which replies to ignore and which ones not to, then they should probably due a bit more basic research before deciding anyway. Dont blame the forum for its variety of opinions and replies, Id rather have than that just one or two people replying.

 

[PaulD 10+ year member]

yes and no - other "opinions" are ok as long as the real facts are made obvious. The funny part is when you have people that are just plain old wrong and refuse to admit it, they just drag it on arguing about every little point to save face. I guess it can be really hard for some guys egos to admit they are actually wrong.

 

[soldiermedic 10+ year member]

I have a question in regards to a comment made earlier: In a small system setup, would a cap be useful at all? I don't see myself having to buying a new alt, whole new battery or even a second one to alleviate the dimming issue (which lasts a fraction of a second per demand of the amp), but still enough to annoy me) when I am only running an average of 1100 watts RMS in my blazer (I think that is a good definition of a small setup.).

 

[soldiermedic 10+ year member]

Your correct.. if you have enough batteries and they store enough power to provide the draw amperage wise.. to make up for the lack coming from the ALT you sure can.. the ALT has a better chance to recharge the batteries between power demands /slops/musical notes during transitions..
But again thats the key.. Batteries are different than caps, as they actually store and retain voltage and amperage..

That part is more dependent on actual setup..

If you take my example.. if i put like 3~4 batteries i could run it all day long and probally not have to upgrade my ALT, because the 3~4 bats would provide the power I need and the alt would have a better chance of recharging..

If I took the same example and only had 2 batteries... the ALT would work harder.. and probably have a 50/50 chance vs the 4 bats.. of either sufficing or having he same problem..

Again dependent on the setup.. but for the most part.. people looking through these threads are probably running stock Alt.. if they were even considering a cap and wont be putting over sized Bats in front and back.. as they are probably not going to know how to get the figure they need.. to select the right bats to provide enough power to get away with out upgrading the ALT..

^^This is me. I did the big 3 and got a new battery for the original upgrade (RF T-800-4 amp on 6" polk MOMO components w/no sub) which was a yellow top. Worked just fine until I upgraded the sub and amp

 

[LiveAudio911 10+ year member]

I'm not a fan of Yellow tops, they have really low power rating compared to Kentik's.. esp for the price.. bottom line is your lights dim because there is not enough amperage in the electrical system to meet the demand, so when your amps pull power.. (its being shared with everything else) amperage drops so your lights dim..

Having a bigger battery could and might correct it if its big enough and can store enough power to allow time for the alt to recharge the bat... but even if that if you can not get a battery big enough to supply the amperage the alt lacks to produce... then you would need to consider either putting a second battery in to supply reinforcement, or upgrade the alt..

You probably need to find out what your alt is putting out... some stock alts are very low.. and offer OEM upgrades to a few amps higher.. sometimes can help.. while other times you have to buy an aftermarket alt that can produce 200 amp or so..

Basically everything depends on the car/truck... each one uses different amounts of power.. but for simplistic reasons (Lame's terms) a typical vehicle will use about 70 amps of power running give or take..

Typical 1,000 watts of rms power (not exact but just as general guide) 70 amps or more.. depending on the amp.. most stock alts produce between 80ish give or take up to 130 amps (give or take)

So for example lets say these values were some what close.. (which they are not by any means accurate) this example you would need 140 amps constant, of current available in the electrical system, now the key here is.. so you basically you would need a big enough battery or batteries to compensate for the lack of ability of the alt to produce that much..

I suppose in this instance an HC2000 Could possibly* supply the power needed allow the under sized alt to keep up with the electrical demands somewhat.. but the core problem still is the alt can not recharge the battery(ies) properly.. you could probably get away with it for a short while but if you never allowed the bats to recharge you would probably at some point see the lack of amperage in the system return, but that would be very dependent on the use of the amps.. I'm sure you do not run around blaring your stereo to every single song.. or constantly pull full power.. so more than likly in this case you would probally get away with it being the alt would have time to recharge the battery and keep up..

Again just my opinion... and not really sure how 'correct' I am..

 

[bubbagumper6 5,000+ posts]

The lights dim because the voltage drops, not the current (what you call amperage). Batteries only supply power when the voltage drops down past their resting voltage. Normal systems run at about 14.4V and good batts sit at about 13ishV. Meaning that between that 14.4 and 13 all the power has to come from the alt. The dimming comes in because once the voltage drops to 13V your batts don't have enough power stored to keep it from dropping further and the headlights output is directly related to it's incoming voltage (i.e. less voltage, less bright (dimming)). Adding more batteries will definitely help keep your voltage at least at the resting voltage but it puts more strain on the alternator because it has to try and charge them back up in the low demand times (in between bass notes). Running extra batteries on a stock alt can cause it to die prematurely. When I pulled the stock alt off my first car it was completely black inside, I was kind of surprised it was still running at all.

 

[LiveAudio911 10+ year member]

The lights dim because the voltage drops, not the current (what you call amperage). Batteries only supply power when the voltage drops down past their resting voltage. Normal systems run at about 14.4V and good batts sit at about 13ishV. Meaning that between that 14.4 and 13 all the power has to come from the alt. The dimming comes in because once the voltage drops to 13V your batts don't have enough power stored to keep it from dropping further and the headlights output is directly related to it's incoming voltage (i.e. less voltage, less bright (dimming)). Adding more batteries will definitely help keep your voltage at least at the resting voltage but it puts more strain on the alternator because it has to try and charge them back up in the low demand times (in between bass notes). Running extra batteries on a stock alt can cause it to die prematurely. When I pulled the stock alt off my first car it was completely black inside, I was kind of surprised it was still running at all.

Yeah more or less what I said.. but one thing.. Amperage is the measure, flow of the voltage.. your alt doesn't stop putting out 14.xx yeah there is a drop in voltage because you do not have enough amperage to keep the system at the voltage.. so a drop in the amperage (flow of the voltage) causes a drop in voltage..

 

[bubbagumper6 5,000+ posts]

Yeah more or less what I said.. but one thing.. Amperage is the measure, flow of the voltage.. your alt doesn't stop putting out 14.xx yeah there is a drop in voltage because you do not have enough amperage to keep the system at the voltage.. so a drop in the amperage (flow of the voltage) causes a drop in voltage..

Current doesn't measure the flow of Voltage...it's just current. Technically it's the amount of charge passing through a single point of wire per unit of time. They are related via ohm's law but one doesn't measure the other.

 

[LiveAudio911 10+ year member]

Current doesn't measure the flow of Voltage...it's just current. Technically it's the amount of charge passing through a single point of wire per unit of time. They are related via ohm's law but one doesn't measure the other.

Say what??? Amperage, or current, is a measure of the amount of electrons moving in a circuit. Yes voltage is the force of the energy... yes a drop in voltage at the battery in this case would drop the voltage of the system.. but when dealing with the alternator.. there is no drop in voltage..

With all things being equal with in the alt. it produces the same voltage regardless of the demand.. what it lacks is the force to produce enough... force-voltage- to keep the flow amperage.. up in the system and to keep the voltage stable at the battery level..

You are correct on one hand.. but are incorrect when dealing with the altenator.. a decrease at the battery is just that.. the alt will continue to produce a 14.v load at its given amperage..

In the electrical system its just not enough to keep the voltage stable if its not producing enough amps.. (voltage at a given rate) they go and in hand.

 

[helotaxi 5,000+ posts]

More batteries are NOT more strain UNLESS the drain from the system is so high that the alternator has no chance of meeting the average demand and the batteries are in a continuous state of discharge. The amount of energy pulled during a transient is the same whether it has come from one battery or 100 so the alt is not being asked to work any harder. 2 batteries wired in parallel can deliver that energy more efficiently because the total ESR is reduced by the parallel wiring.

 

[ahole-ic]

More batteries are NOT more strain UNLESS the drain from the system is so high that the alternator has no chance of meeting the average demand and the batteries are in a continuous state of discharge. The amount of energy pulled during a transient is the same whether it has come from one battery or 100 so the alt is not being asked to work any harder. 2 batteries wired in parallel can deliver that energy more efficiently because the total ESR is reduced by the parallel wiring.

This is also an argument that capacitors are not a strain on the alternator. They draw MUCH less than batteries because they actually charge up to the system voltage thus no longer drawing current until discharged. Since their reserve is so small, they also draw much less than batts. This is exactly why telling people capacitors are HURTING them is nonsense. They simply aren't helping either.

 

[helotaxi 5,000+ posts]

This is exactly why telling people capacitors are HURTING them is nonsense. They simply aren't helping either.

Precisely from an electrical standpoint; but they are hurting since they pulled budgetary resources away from something else that would have made a difference like a more efficient amp or better speakers.

 

[ahole-ic]

Precisely from an electrical standpoint; but they are hurting since they pulled budgetary resources away from something else that would have made a difference like a more efficient amp or better speakers.

Then you have to say the same thing only 100 fold for a battery. You simply cannot make the argument FOR a battery but against a capacitor on these grounds is what I'm saying.

Also, we know that it takes a difference of potential for current to flow, so how exactly are these capacitors stealing current from a device? When the alt raises the voltage back up, it's because demand is lowered. This allows the devices to operate as normal again, and the capacitor to recharge.

Please elaborate on your theory, and then I will gladly explain how you are wrong.

 

[helotaxi 5,000+ posts]

By resources I meant $$$. Nothing to do with electrics.

And you cannot compare batteries and caps. A battery can actually maintain voltage where a cap cannot.

 

[bubbagumper6 5,000+ posts]

More batteries are NOT more strain UNLESS the drain from the system is so high that the alternator has no chance of meeting the average demand and the batteries are in a continuous state of discharge. The amount of energy pulled during a transient is the same whether it has come from one battery or 100 so the alt is not being asked to work any harder. 2 batteries wired in parallel can deliver that energy more efficiently because the total ESR is reduced by the parallel wiring.

Idk, I think I'm going to have to disagree. The system gets strained (and lights dim) because the power isn't there to give to the amplifier so the voltage drops and you could basically say the system fails. Adding another battery will add to your available power at any given time, thus supplying more of the power that the amplifier wants and getting it closer to "passing" (instead of failing). Thus the alternator is going to have to recharge twice the amount of power it did before. I mean a battery only has a limited amount of power it can give out before falling below the resting voltage.

Idk, maybe I'm wrong, I'd like it if you could get as technical as possible simply for the fact that I like to learn things...