I can believe that. Dimming the lights is not hard to do in most vehicles (just turning the ignition off will do it), and I imagine that the alternator in a 3-liter passenger car is mid-duty at best. No_BS, on the other hand, has two trucks in his gallery, both of which have pretty good-sized V-8s and, I would venture, considerably larger alternators. He's also seeing some rather large voltage drops as measured by his voltmeter.

300W at 13.2V is less than 23 amps. We won't know for sure, but I'd be surprised if his alternator can't provide that, unless, as stated earlier, he's idling really low. My guess is still that he can improve matters merely by cleaning contacts and upgrading some alternator cabling.

 

agreed.

Worst case-scenario; I still would not use in a cap. Most alternator/starter shops will rewind a stock alt for about $.75-1.00/amp. Hmmmm.... 120 or 130A alt; still a much better plan than a capacitor. (Or a "band-aid" as I like to call them. ) If your alternator can't keep up now, a capacitor is only going to be an added strain on your brushes, and inevitably will kill your alternator even faster.

 

It idles at about 650, so I should try new wiring and improved grounds first?

 

i have to agree with geezer and all others who said no cap. i would in fact look into the wiring. the battery serves 2 functions, to provide power for the starter to crank over the engine and to supply power when the vehicle is either on accesory or the alt is over burdoned. sure a capacitor will help with the lights diming but it also adds another draw to the electrical circuit. it will also add resistance when it is discharged. the big 3 things u should do when u add a stereo is upgrade the wiring (also check ground, etc...), make sure the electrical system is in good operating order, and finally ethier upgrade the alt or battry or both. the upgradin of the wire allows more current to flow throughout the system and supply the amp sufficently.

a cap is just a band-aid to "cover" up a problem down the road. this subject has been covered more times than i can think of. listed below are several links that i hope will clear up the mis-conceptions of caps. PLEASE READ THEM!
http://www.termpro.com/cgi-bin/ubb/u...;f=22;t=002092
https://www.ford-trucks.com/yabbgold...num=1041205623
^---this one has been giving me some trouble so im not sure if it is working at the moment.

 

Sounds like your car can't give up the juice that fast. How is your amp hooked up exactly. I have mine hooked straight to the battery. At 300watts, you could only pull about 25 amps at 12 volts(engine off) and a hair over 20 amps if the engine is on, 14.4 volts. You pull hundreds of amps turning over your motor to start your car. The dimming shouldn't happen. Heck I have a little radio controlled car that runs double the amps of your sub and it runs only off of a little battery pack. It may be a sign of a bad car battery or soon to be bad car battery. Your alternator may be going out on you, but your voltage seems to be normal when you're not running your subs, right? You should have somewhere around 14.4 volts with the engine is running(No = alternator problem) and 12 volts when the engine is off(No = battery problem). Now a cap would solve the issue of dimming, but it doesn't fix the problem. Check the other two first.
As far as your amp going out on you, what brand do you have? I run a Pioneer amp, and it does the same thing. I contacted Pioneer about it and found out it's actually a built in protection feature. Most amps don't have this. They'll run till you fry them. My Pioneer is self-protecting. Yours may be the same. Otherwise, it's a power issue. Either you have a poor ground or you can't provide enough juice to the amp, too low of voltage and shuts off. The cutting out and the dimming may be hand-in-hand. Check the battery and alternator first. If both are good, then check wiring to amp. Make sure you have a good ground connection and that your positive connections has direct access to power, i.e. connected to battery.

 

I've been following this thread, and because of it I'm wondering if I should consider upgrading my wiring.

My truck is a 2003 F-150 FX4 (5.4L) with towing package. The tow option includes an upgraded electrical system, but I'm wondering if it's anything more than a higher-durability battery.

So, my questions are: Considering what I've got, should I still consider upgrading the wiring? How about if I put on a 200A alternator, will I need to upgrade the wiring then? If the wiring needs an upgrade, what guage should I use? (I'm thinking 1/0.) Exactly which wires need to be upgraded to solidify the system without overdoing it, and wasting time/money?

 

Yes, you ESPECIALLY will need to do this when upgrading to a HO alternator. Personally, I'd still do it even with a stock setup, but it's your call.

Alternator>battery
battery>chassis
engine>chassis

2AWG is the biggest you'll ever need. 1/0 is just a waste of $$$, IMO.

 

Be sure to use a high strand count wire, as well as making sure the contact between the alternator/battery and ground is tight and clean. Remove ANY paint between the connections.

 

I just re-did my amp ground wire, I'll see if that helps at all first. AngerFord, it's a kenwood amp and it is connected directly to the battery. My old ground connection was a little sketchy so I just went out and made a new one to the body on bare metal. Hopefully that'll help some, I'll keep you posted.

 

Nah, didn't make much of a difference, but it does make me feel better about it.

 

I have a couple questions as far as upgrading the wiring form alt to battery do I need to change the Black/Orange wire from the alt>battery (this is an 84 f150) http://www.cybrrpartspro.com/Chilton.../85766114L.gif


I upgraded my amp from my an old sherwood (50wx2 Rms) to a profile CA600 (150 wx2 RMS) runnning 4GA from batt to a distribution block. i want to use that sherwood to run my door speakers (nice having two sets of preamps :-) ) which are currently being run by the HU (panasonic CQ-DF583U)


I just want to make my electrical efficient enough to avoid having to get a HO alternator. I want to make sure that my system is up to snuff..My voltage regulator/alternator are less than 2 years old. didn't een need to replace the alt.

Thanks