amp/subs = lower rpm's?

[Ryan K]

Whenever I turn on my 460watt (puny) amp and my subs, the rpm drops a little, then climbs back to normal. I notice this when I am in idle and not when im driving. I also notice that my headlights dim somewhat whenever I use them too. Im just wondering if maybe this has something to do with my battery or does this happen to lots of people.

[Joel_CA]

Turning on your system applies a load to the electrical system. This will momentarily drop your idle speed... same thing happens when turning on your head lamps though maybe not as noticable.

Joel, CA

[jphillips]

it will actually happen everytime the bass hits. on a good long bass note you can actually drop your voltage to under 12 depending on the size of amp and the coralating power wire. I chose to install a 5 farad power cap to help compensate for this. The capacitor has the ability to charge and discharge at 10x the normal charging system.

[Joel_CA]

I've got a 1 Farad Cap stabilizing the power supply to my Rockford amps. Works great!

Joel, CA

[Ryan K]

well for my 460w puny amp, I purchased a Rockford Fosgate .5 ferad cap(500w max). When I was done installing it, when I went to plug in the +positive to the battery it made a big spark. It totally freaked me out, so I turned on the car my subs were not as strong as they usually are, I think my grounding wasnt in the best spot, I connected it to the metal hook for the rear seats. Is this a good grounding spot and is it ok for the battery to spark when I connect it? Anyway I was running out of time last night and just disconnected the whole thing and ill work on it another day.

[Joel_CA]

You're supposed to slow charge the Capacitor with the supplied resistor before hooking it up to direct voltage. If you didn't slow charge the cap, consider yourselft lucky that there was no damage done at this point. On top of that, the positive side of any circuit should be connected 1st- with the ground side of the ciruit being connected LAST. This will reduce the likeliness of a big spark upon connection.
As far as grounding location- find a spot where you can bolt it down directly to a heavy piece of metal on the body. Scrape all of the paint off around that area to make sure that it doesn't get in the way of direct contact with the metal of the vehicle. If you can, you can also beef up the ground strap between the battery negative and the body/engine of the vehicle.

Joel, CA

[Ryan K]

Alright, Test number 2: I pre charged my cap using a moble jumper battery starter. I connected it to my battery (disconnecting the negative from the battery) Started up, but then after I drove for a while I noticed that when i would stop my RPM's would dip all the way to the 1/3 mark (yeah, low) At this time I was driving with my lights on (fog lights too) and at every time I slowed down, the RPM's went low. So I turned off my lights and it would dip but not too low. At about this time I had enough with this cap so I took it off. I then went for a test drive and it was doing the same thing when my lights were on(dippin down to the 1/3 mark). Does this mean I should get a new battery. I have no clue how old my battery is since I bought my ms used. If I bought a new battery, would this fix my problem. Sorry for the long post, and im not the most car-mechanical type of person on knowing what is wrong. Thanks in any advice

p.s. a few months ago I had a problem with my headlight system, my lights were taking so much electricity that it melted the fuse in my fuse box. However I got it fixed and the mechanic took the fog lights and connected to a main fuse, seperate from the headlight fuse. Just wondering if this had anything to do with this Thanks

[Ryan K]

Anyway, I figured it all had something to do with my battery so I purchased a new battery, installed it and all my problems went away! no more low rpms!, no more headlights blinking!, no friggin cap to install! lets celebrate. yay.