30 Farad Capacitor

[palonmar]

Thanks Sir Jhnkvn for the input! Buying a 30 Farad is a really waste of money and misleading. Now I got this conclusion....If the alternator is only rated 12-14 Volts and 80 amperes at peak power demand, then the capacitor no matter how big the capacitance is, it only stores 12-14 Volts 80 Amperes then discharges it when needed. If the Amplifier is pulling 100 Amperes or more * peak power demand during heavy or low bass notes, a capacitor can only give that much for some few seconds! am I correct? TIA...

[jhnkvn]

Nope. A capacitor only stores a very tiny amount of energy compared to that of a battery. They don't need to store alot since their specialty is to provide FAST additional power during the peaks. This is due to their low internal resistance.. in fact, discharging a 1 farad capacitor completely takes the same time it takes for you to blink.

As a hint on their capacity. Richard Clark wrote a damn long article about capacitors way back detailing how they work. Took me an hour to read and I still don't understand 70% of it. I'm not an electrical engineer so I really don't care. But here's an interesting trivia:

Check this link: RadioShack #52 272-1127 Screw-Base Lamp 14.4V 100mA | eBay. That's your typical miniature light bulb that we use everytime we get those damned Meralco blackouts.

In the case of an endurance battle, a 1.5 farad capacitor would power this bulb for 5 minutes. A 20 farad? Maybe around an hour.

This everyday Duracell battery we use.. would keep it running for 2 hours and 15 minutes.

Now think about your car head lights and compare that with your car battery... and you should get a rough idea on how small the capacity is.

Besides, our cars with stock alternators have varying loads. It won't be dishing out 80 amperes at idle.. it probably dishes around 50 amperes. For example: 1500RPM (idle) - 50 amperes, 3000RPM - 70 amperes, 4000RPM - 80 amperes.

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Personally, I try to avoid car electrical system topics since they're a pain to discuss. To be more specific, you need to compute for your amperes. I think this is a good read if you're a beginner to it: Car Audio Capacitors vs. Power Cells - Knowledge Base

In a nutshell, here's what I think:
20 farad capacitor - useless for the money. You get the same goodies from a 2-3 farad cap.

2-3 farad capacitor - might help your dimming issues especially if it only dims from time to time. What I mean by time to time is let's say you inserted Far East Movement's CD there. You played a 2 minute track and it only dimmed for 5 seconds, 5 on each 1second peak.. in that case, it would help. But if you dim for 1 minute and 30 sec out of the 2minute track, give up on caps.

An aftermarket Stinger battery - would help definitely on your overall electricals but might not remedy your dimming lights issue.

An aftermarket HO alternator - now that's where we're talking..

However, I would first like you to check up on your level matching. Did a professional car audio shop do it for you? Which one? Remember that the gain control on the mono amplifier isn't a volume control. It's one of the easiest mistakes newbies commit hence they tend to clip easily. So before you commit yourselves to any of the fixes, check up on your current system first. Throw in an appointment with the car audio shop to check on your battery and alternator's condition to make sure while you're at it.

[jhnkvn]

Nope. A capacitor only stores a very tiny amount of energy compared to that of a battery. They don't need to store alot since their specialty is to provide FAST additional power during the peaks. This is due to their low internal resistance.. in fact, discharging a 1 farad capacitor completely takes the same time it takes for you to blink.

As a hint on their capacity. Richard Clark wrote a damn long article about capacitors way back detailing how they work. Took me an hour to read and I still don't understand 70% of it. I'm not an electrical engineer so I really don't care. But here's an interesting trivia:

Check this link: RadioShack #52 272-1127 Screw-Base Lamp 14.4V 100mA | eBay. That's your typical miniature light bulb that we use everytime we get those damned Meralco blackouts.

In the case of an endurance battle, a 1.5 farad capacitor would power this bulb for 5 minutes. A 20 farad? Maybe around an hour.

This everyday Duracell battery we use.. would keep it running for 2 hours and 15 minutes.

Now think about your car head lights and compare that with your car battery... and you should get a rough idea on how small the capacity is.

Besides, our cars with stock alternators have varying loads. It won't be dishing out 80 amperes at idle.. it probably dishes around 50 amperes. For example: 1500RPM (idle) - 50 amperes, 3000RPM - 70 amperes, 4000RPM - 80 amperes.

---

Personally, I try to avoid car electrical system topics since they're a pain to discuss. To be more specific, you need to compute for your amperes. I think this is a good read if you're a beginner to it: Car Audio Capacitors vs. Power Cells - Knowledge Base

In a nutshell, here's what I think:
20 farad capacitor - useless for the money. You get the same goodies from a 2-3 farad cap.

2-3 farad capacitor - might help your dimming issues especially if it only dims from time to time. What I mean by time to time is let's say you inserted Far East Movement's CD there. You played a 2 minute track and it only dimmed for 5 seconds, 5 on each 1second peak.. in that case, it would help. But if you dim for 1 minute and 30 sec out of the 2minute track, give up on caps.

An aftermarket Stinger battery - would help definitely on your overall electricals but might not remedy your dimming lights issue.

An aftermarket HO alternator - now that's where we're talking..

However, I would first like you to check up on your level matching. Did a professional car audio shop do it for you? Which one? Remember that the gain control on the mono amplifier isn't a volume control. It's one of the easiest mistakes newbies commit hence they tend to clip easily. So before you commit yourselves to any of the fixes, check up on your current system first. Throw in an appointment with the car audio shop to check on your battery and alternator's condition to make sure while you're at it.

[jhnkvn]

Thanks Sir Jhnkvn for the input! Buying a 30 Farad is a really waste of money and misleading. Now I got this conclusion....If the alternator is only rated 12-14 Volts and 80 amperes at peak power demand, then the capacitor no matter how big the capacitance is, it only stores 12-14 Volts 80 Amperes then discharges it when needed. If the Amplifier is pulling 100 Amperes or more * peak power demand during heavy or low bass notes, a capacitor can only give that much for some few seconds! am I correct? TIA...

For some reason, the detailed post I typed yesterday was "for moderator approval" and ended up not being posted at all. WTF is happening to Tsikot >_>

[jhnkvn]

I'll keep this short nalang ;) and in bullet format since I'm a bit annoyed how my previous post didn't post properly.

If the alternator is only rated 12-14 Volts and 80 amperes at peak power demand, then the capacitor no matter how big the capacitance is, it only stores 12-14 Volts 80 Amperes then discharges it when needed.

A capacitor isn't known for its massive capacity to hold joules but rather its ability to discharge quickly. How quick? A 1 farad cap would discharge itself faster than a kick drum beat.. or around half the time it takes for you to blink your eyes. We're talking about milliseconds here.

As for capacity. Think of your regular flashlight you use during brownouts. Try to picture the lightbulb.. now a typical 1.5 farad capacitor has enough power to power that bulb for around 5 minutes before giving up. A 20 farad capacitor would last around an hour. Your typical 9V Duracell battery would power it for 2 hours and a half. Now if you think of powering a light bulb using your car battery... you should know more or less how long it'll take

The dimming of the lights is caused by your voltage dropping from the typical 13-14V to 12V which is battery-territory. Let's say in a perfect scenario where your alternator is outputting 80A and your amplifier is drawing 100A continuously, kahit maglagay ka capacitor.. it's useless since your charging system can't keep up. But if your normal amplifier is drawing, let's say, 50A on average and reaches a peak of 81A in one second (causing your charging system to dip into the battery territory since the alternator cannot provide the output) then capacitor would do its work in providing the extra 1A. But if the capacitor is continually being emptied and it isn't finished charging, it's pretty much useless and presents to your alternator another load to "charge" up like your battery.

The first I would suggest you do is make sure you're matching levels correctly. The subwoofer amplifier's gain control is not its volume control. I've seen alot of newbies turn their gain all the way up, clip the amplifier then kill the sub. Dimming of the lights is a symptom of clipping since clipping wildly increases the amp's load beyond its normal operating output.

Now if you're sure you're good, ask your suki car audio shop to inspect your battery and alternator to make sure they're not faulty. (It's very rare but at least you made sure right? Rather than scooping up a HO alternator only for the guy to tell you your battery's the culprit).

Solutions to your light dimming and what I think is the outcome.
1. 20 farad capacitor - waste of money.
2. 2-3 farad capacitor - might help if your scenario's like the one above. If you're dimming for maybe 5 seconds out of a 2 minute Far East Movement track, a cap might help. But if you're dimming for minutes... it's hopeless.
3. New primary battery - might help.. but I'm running stock Hyundai batteries. I'd say isuki mo muna yun Motolite Excel batteries mo since it's only a few months old. Changing to AGM Stinger batteries would improve your electricals though ;)
4. New secondary battery - it won't solve your light dimming and presents another load to the alternator. It helps in extending the time you can jam while the engine's off though.
5. New high-output alternator - it's the sure way.

If you did the Big Three procedures using 2GA wires. Don't let others fool you that you need 1/0GA wires. Gaano ba kalaki alternator habol mo? If you're eyeing the 200A HO alternator, by all means go for 1/0GA. But if it's around 120A, 2GA suffices na. Heck, my Big "Two" (since 2/3 procedures done na saakin) uses 4GA wires and comes factory-stock.

[jhnkvn]

EDIT: I'll keep this short nalang -> In the end, I typed and ended up with a long one. Forgive my fingers. Haha...

[palonmar]

That's a very informative input sir jhnkvn, everybody in this forum will benefit from that. I like reading and a long one is nice to read.

I used to be listening to Bass Music/ Sounds as others may call it, like Bass 305, Bass Mechanic and the like. There are bass tracks that delivers heavy and low bass notes during the whole duration of the track and so a capacitor like you said cannot give any help to my system. Even though I'am using a 1 Farad Cap, my headlight tends to dim and my amplifier tends to clip during those periods, a description of what you said. The capacitor got no time to recharge but to be discharged and so becomes another load to alternator.

I've googled about the Deep Cycle Batteries like Stinger, Optima etc.. I don't know how much they are selling those in audio shops, maybe even more than my Excel. Is it true that DCB's produces less current than the standard Lead Acid Batteries because it has less surface area than LAB's? Also, DCB's can survive to be drained multiple times while the LAB's will be damaged if discharged completely. I don't know if that info is correct, here's the link:Charging System Basics

Based from your input, it seems I don't have to replace my Motolite Excel and a need for a capacitor if I have an ample power supply coming from the alternator. I guess 110A-120A would satisfy my ampliers power demand. May I ask sir if you have any idea how much it cost? TIA

[jhnkvn]

As for the drained multiple times, that's true. AGM batteries can be drained hundreds of times as opposed to our standard dry lead cell batteries. That's why it's a horror for us if we completely drain the battery of our Motolites

Starting batteries have high ampere ratings for sudden surges (ex. starting your car) but is relatively poor in overall capacity and quickness (they have high resistance from what I believe). Besides, AGM batteries charge faster for what it's worth. For SPL applications where the system is being played loud, having a better battery like Stingers would be beneficial.

A very good beginner read on this topic is Optima's FAQ page: Optima Battery FAQ - Frequently Asked Questions or if you prefer shorter but informative reads: How To - Car Stereo - Amps, Alternators, and Batteries: Upgrading Your Electrical System

Price Guide (just so you know):
An Optima Yellow-Top retails around 12k
Stinger SPV44 is around 10k
Motolite's at 5k

As for aftermarket HO-alternator prices, I go no idea what's the going rate. I've never inquired after all... . However, some shops offer brand-new HO alternators as it is while others simply take your alternator and change out the internals. With the latter being the cheaper option. From my memory, a branded brand-new HO alternator at around 200amps will retail around 30k (you can then further discount this)

[palonmar]

If that is the case, maybe I will just upgrade my existing alternator and let them change the internal. There are alternator shops near may place, I hope there's HO alt that can fit to my Lancer or know how to upgrade my stock. Anyway I can save some money for that upgrade. thanks for the advise.

[Zdre_Wulf]

the best would be to install a second battery and upgrade the alternator... the30Farad cap is useful for spotwelding capacitor bank

a capacitor is charged quickly as it can be discharged...it stores charges that is released whenever the voltage falls.... 1farad would be enough for "peaks" and for smoothing out the noise in the electrical system