Thread: Putting in a switch for subwoofers

Originally Posted by SINister

i got the cap a long time ago i just had it stored since my old amp died. but with my old setup in my old car the amp was hurting my electrical system and the cap stoped that. i didnt notice sound quality go bad since it was installed. ... are you saying its a bad idea with our cars? or just in general? i am searching for a stuff that explains why its bad but i cant find anything.

If the cap is installed correctly, it doesn't hurt anything. It also doesn't help anything.

I only had a question on putting a switch into the setup not whether im an idiot or not for having a cap

Originally Posted by EJRJR91

I only had a question on putting a switch into the setup not whether im an idiot or not for having a cap

Doesn't make you an idiot. Some of us have caps collecting dust in our basements. We're just trying to help you out, bro.

thanks for the help on the switch, the cap is going in, my car's electrical setup is stock so im attempting to avoid any battery drains 30 miles from home while im in the city is all, so im putting in the cap to avoid ne problems, i've left a cell phone charging with my car off and my battery got drained, i'm a lil over cautious now about it

Again cars fine unless i leave electrical on with car off, its just added precaution against draining the battery. Much cheaper than a new batter bc thats not the issue as ive replaced that already

dead cell in ya batt or its killing one... i've left lights on overnight and and crank right up.. hell ive locked my keys in my car with my radio/system on for hours and it crunk up.. no cap. just a good batt

Unless someone can tell le specifically y a cap is a bad thing its going in, even if u do tell me its prob going in lol ive seen it at work nd it doesnt harm the car but does help when you draw a large amt of extra power that was not planned for wen the car was designed such as subwoofers, ive seen headlights dim ive seen batteries drain so im just being cautious against wat ive actually seen

well imo if your only runnin a couple tens.. i dont see a problem nor any issues with power drain..... i cant speak on cap being bad because i havent messed with them.. but then again.. i didnt need em.. and ive hooked up and used systems up to 4 12's and 3 15's.. just my opinion i understand your concern tho

Originally Posted by EJRJR91

Again cars fine unless i leave electrical on with car off, its just added precaution against draining the battery. Much cheaper than a new batter bc thats not the issue as ive replaced that already

With a Electorlyric Capacitor, They can go bad, When they do Theres a few methods of Failure.

First is Internal Discharge. Which in turn Causes the Capacitor to Consume electicity to replace when it is discharging. Creating a Constant current draw. Resulting in a dead battery. If that carries on..

Well. The outcome isnt too pretty.

Heres a Small Scale Cap rated at 560 uF (MicroFarad) and 200 Volts Standard Audio Cap is 1 Farad = 1,000,000 MicroFarad

So That little guy in that video is 1,785.7 Times Smaller than the Capacitor you are putting in your trunk.

A cap will not prevent your battery from draining while the engine is off. The cap will only hold a teeny-tiny minute amount of energy. A single sub hit at a medium volume will more than drain your cap. So, for your own sake, don't rely on it as some sort of fail-safe.

I'm not saying I want the cap for when the car is off, that's y I want the switch so that the amp goes off when I throw the switch and there's no power draw, the cap is so that I'm not drawing too much power from the battery with the car on so that when i do turn the car off the car will start up again

Red top

Originally Posted by EJRJR91

I'm not saying I want the cap for when the car is off, that's y I want the switch so that the amp goes off when I throw the switch and there's no power draw, the cap is so that I'm not drawing too much power from the battery with the car on so that when i do turn the car off the car will start up again

Tell us what you're running for power.

I'm currently running 1000w RMS on stock wiring, powering 4 12" subs. My car starts up every time and I'm using like a $50 surplus battery...

Originally Posted by EJRJR91

the cap is so that I'm not drawing too much power from the battery with the car on so that when i do turn the car off the car will start up again

This is not a thing.

If you have your system wired correctly there shouldn't be any draw on the battery from your subs and amp with the car and ignition turned off, if there is it is NOT wired correctly, because you should be using the turn on signal from the head unit to turn on the amp and when the radio is off so is the amp= no power draw. Am I explaining this simple enough for you?

Originally Posted by simbah

If you have your system wired correctly there shouldn't be any draw on the battery from your subs and amp with the car and ignition turned off, if there is it is NOT wired correctly, because you should be using the turn on signal from the head unit to turn on the amp and when the radio is off so is the amp= no power draw. Am I explaining this simple enough for you?

Besides the fact that you sound like a prick, I think you explained it clearly enough. After reading this thread, it sounds as though there has been a ton of S*&t thrown around so let me sum this up in a clear and concise manner.

1. Your amplifiers are turned off by the head unit. When your stereo isn't on, there should be no draw from your amplifiers.
2. If you are running a high power audio system, a capacitor can and will help level out the voltage input into the amplifiers by acting as a small voltage buffer between the varying voltage demand of the amplifier and the fairly constant out voltage of your alternator struggling to keep the voltage constant. So yes, they do work however this will not fix your issue.
3. It sounds like you have an issue with your electrical system discharging constantly, even when it shouldn't be. This is a totally different issue that should be explored further to figure out where the draw is coming from. Could be a small short somewhere, a faulty amp, relay, capacitor....
4. A secondary battery in will extend the life of your car, more battery capacity is more energy storage, but again, thats not your issue. You have plenty of electricity assuming your alternator is working correctly and your battery isn't bad, but you seem to be draining that electricity much to quickly.

All this being said, we on this forum can't help with your discharge problem, only point at one of the zillion things it could be. If you are not comfortable going through this process then I would take it to any auto mechanic who should be able to solve your problem quickly. Sorry for all the confusion in this thread, we all have our own opinions with some of it biased on fact, and some not.

Best of luck!

It could be as simple as a bad battery. They will self discharge when they are wore out. It can really happen at any age. At the shop we have had a few new ones go after a few weeks.