I am going to be hooking up two Rockford Amps (P4004 and P5002) running 400 and 500 total RMS Watts or 1200 and 1500 Max Power respectively. I was wondering if I will be requiring a capacitor (1 Farad) so that the amps do not drain my system. The saleman even recommended that I use two capacitors. Any assistance would be welcomed.

 

Do a search, caps are a waste of money.....

 

some think they are some don't, unless you get a bigger alternator you may not need one but with stock you might. with my system before my lights dimmed like crazy but now they don't. go fig and i only have a 1 farat cap. it just stabilizes your electrical system by having the amp draw most of the power from the cap instead of directly from the battery.

 

Not exactly how it works....

 

ok fine then tell my why my last alternator blew up and the lights dimmed with the new one? its an 80 amp alternator which should be plenty for what im running. and after putting in the cap the lights stopped dimming.. please answer that i would really like to know why since you know caps don't work at all according to you.

see what a cap does is stores energy for the amps to use during hte heavy bass hits, and instead of linking up everything through the battery and drawing all the power away directly from the battery it takes it away from the cap first therefore drawing less from the battery and reduces stress on the alternator . and i remind you all of your electrical stuff is hooked up to the battery.

and yes it does stabilize your electrical system, because on the heavy hits, the amps draw power from the battery and if there isnt' enough stored energy it will draw it from other things like lights etc... hence the dimming in lights most people notice. and by having the cap its instant power and it shares the load with the battery therefore not requiring the battery to use as much power for the amps, therefor not taking anything away from the accessories (lights etc..)

 

I never said “caps don't work at all”, did I. They can help in some cases, but even then they are just a quick fix to over come short comings in the electrical system. If the electrical system is where it should be there is no need for them. Fix the problems in the electrical system, don’t cover them up. It’s like having something that works, and having something that works right. There’s a difference.

“ok fine then tell my why my last alternator blew up and the lights dimmed with the new one? its an 80 amp alternator which should be plenty for what im running.”
Well, I would need more info before I could give any kind of a detailed answer. Quick answer is that the electrical system isn’t up-to-snuff. 80A Alt is pretty darn small though. But that depends on a lot of other thing to. Just the exterior lights will pull more then 10A. Then the HU itself (easily 5-8A there on the “loud” notes), computer and fuel injectors (if an FI car), ignition system, engine fan, blower fan, dash lights… What do you have for amp? How many and what size fuses are on them? Have you up graded any of the electrical system? The electrical systems in these cars is just barley adequate for stock, add amps and stuff and you’re pushing it.

“and yes it does stabilize your electrical system, because on the heavy hits, the amps draw power from the battery and if there isnt' enough stored energy it will draw it from other things like lights etc”
Wow, your light can supply energy to the amp? Neat lights. In every other car in the word, there isn’t enough power “in the system” for the lights and amps and all, then voltage drop, and that’s why they dim. There is a difference. It’s subtle, but there. You need to understand all the intricacies of how these things work together.

If you run into dimming lights, upgrade the electrical system. Not just the alternator, but charge wires, engine grounds, whatever it needs. All of it if needed. Then no more dimming lights and no cap. The right way.
Need more? Search, it’s been gone over to death in this forum. All of the answers are there.

 

I answered a post about this about a week ago or so.... I put a few links on with info about caps, electrical theory behind it as well. but yes, it is an opinion thing, and I agree with NeedAz on this one. However many people will tell you how great they are, how much they helped them, etc....
What's the expression? snake oil? "control group?" sugar pill? placebo effect. -J

 

caps are a waste of money!

i r

 

caps are a waste of money!

i run a good car audio system with no cap. BUT.. my lights always dim when the sub pulses, so what i did was just hook up a second car battery. Solved the problem real quick. And, no need for a useless cap.

i was always told, if you could afford or want to spend the extra few bucks, just go with a second battery. They work much better.
And now that im running all of it. i believe it.

 

 

If during big hits you notice your lights dimming and everything is wired using the proper guage, then I say get a cap. The problem is that cheap caps won't help much and too often they are used without realizing proper guage wires and a better alternator would solve the problem. I had great results when I added my friends cap, but I just opted to get rid of the amp instead.

 

like a few of us will say over and over on this topic, make sure you've upgraded your wiring under the hood first. do the big 3 (and if you dont know what it is, there's plenty of info on it under the "search" button ) before you do anything else. if your charging system's wiring to not 4ga or bigger (and it aint stock), do it now. i've been running 2 class a/b amps (one 2x50 rms and one 1x400 rms) and theres no dimming.

majority of caps arent built to be useful, and the ones with meters on them are even more of a waste.

 

You're better off getting an HO alternator. For how much you're going to spend on the cap, you might as well just spend a little bit more and solve the problem, not bandaid it. The only way I actually AGREE with the use of a cap, is if you've already upgraded the alternator, done the "big 3" and got a yellow-top battery and you're STILL pulling too much power. But after all those upgrades, you're only gonna see that kinda drain on a true SPL car... not a daily driver.