Since the recent cap discussion at CAF I have had some questions. Now knowing about the short period of time where the voltage drops well below 12v during the transition of switching from alternator to battery power I am curious about cap sizes. Since we are just working with a period of time that I dont seeit really mattering much on how much power you are running. After all, how long this period is reliant on the battery not the power you use. Will running 2000w vs 1000w really show a big difference on how far the voltage drops during this transition phase? If so what do you recommend on cap size:wattage? Do you support the 500w:1F that I often see?
You could actually help me finish this page: an article that I've recently made to explain batteries, capacitors, alternators I believe that it's pretty complete... but at this point, could use some critiquing, help me decide whether it's finished or not. I know one tweak I need to remove - I have a sentence in there that says something like "heck, maybe you even want to buy one of those big square-style 30F capacitors..." I've been reminded that the big square style caps were the ones that RC used in his testing, showing high ESR that virtually nullifies it's own capacitance, and causes the capacitor to be a constant load on the electrical system, essentially... And I need to include that sort of wording inside my article. To answer your main question though... It's not really about power, as much as it's about usage... and that's not something you can put a generalization on.. like "1F per each 500w". One person might have a 1000w system, and 1F might be plenty (ahem... cough cough... me ahem.. cough).. While another person might have a 500w system, and 1F is hardly enough. It depends on the music that you listen to, how much bass it has, how often those peaks last, how much you are really pushing your amplifiers, how bass-heavy you have it, etc... But also, it depends on your electrical system - how large your alternator is, how large your battery is... how fast your battery is, etc. Generally, more is better, until you start to get crazy... 5 or 6 can style caps is a bit crazy, IMO. At any rate, Ikesound has caps CHEAP... For like $35 you could get a 1F cap... for under $50 a 1.5F cap... etc. Granted, they are brand names like Pyramid and Boss.. :lol: But seriously, those can style caps I believe are only made in 1 or 2 plants in the world.. and you can differentiate by voltage. 20v caps are "better" than 16v caps.. but even 16v is higher than the 14.4 that they'd ever charge up to, so no big deal either way... but I believe the 20v ones come from the one plant, the 16v come from the other... No one builds their own, so buying the Pyramid cap is essentially the same as buying the Brax cap.... and a can of spraypaint can be had for $2.
I am at work right now and I am a bit bust tonight but Ill read through that tomorrow and let you know if I see anything I would change. I would be honored to critique your work Silly me of not thinking of the different variables that would change things. Pretty obvious that all of those things would affect it. But what do you think about the amount of power used? I know that with more power you are likely to drop voltage quicker due to the higher demand but do you think that there would be a noticable difference in how far the voltage actually drops here since the lag time of the battery is so short?
It's not silly, because it's not obvious. 2000w is huge. I'd probably want to do a couple 1F cans, maybe even 1.5F each. Except for one thing.. I can't imagine how you'll actually survive inside that car with your ears intact listening to it at a level where the amp is actually putting OUT 2000w... And if you aren't listening to it at that level, continuously, you might be just dandy with just a single 1F, or 1.5F cap. If you CAN listen to it continuously with the amp actually putting out 2000w... that's really a sign that you've got your poor subs stuffed into a box that's WAY too small for them... and you could probably get 2x-4x (literally) louder by redesigning the box. But at any rate.. IF you were really using your system at that 2000w level... two or three 1F caps would be what I'd do. fortunately, they are really cheap at Ikesound..
Its just to have the potential to be loud. Not going to run it daily at full power. I doubt I ever could. After all, with my SP on 1500w it had the ability to get too loud for me. To be honest my single ported 10w3v2 on 300w is almost enough for me bass wise. But right now my interest is in getting loud. This should definately do it. Will try various sizes and tuning and positioning to get to know my car a little better. When I get bored with being loud I will have a sub amp I should never have to replace. 1400x1 at 4ohms. 2400x1 at 2ohms. I doubt I even need more than that 1400 for daily listening. The rest is just for fun I guess I can test out a 1.5F cap on my front stage and switch to my rear and see if I notice any difference either way. If its beneficial either way Ill keep it and possibly get another for the other amp. Since money isnt really an issue its worth trying Thanks for the input. The real problem is going to be dampening the car. Thats probably going to be a very long ongoing process. That liquid dampening from ED seems pretty damn cheap
Get in touch with Anthony, of SecondSkin... He gives hefty discounts to forum members. B) btw... did I ever mention, I've got all of about 2 sq.ft. of damping material in my Civic?
