Hello everybody, My headlights dim when driving, due to stero equip. I don't know how old the battery in my 04 is, but I can't decide what kind of battery to get. I have heard that a cap, would fix it, and also that it isn't really fixing the problem, just helping. I don't want to hurt anything else in the car. From what I have heard about my amp jlhd750/1, it shouldn't need a cap. I hate having $1,300 tied up in a system, I can't really use right now, and I have only had it for a week!!! HELP!!!
Thanks, Chris

 

I usually do not trust a factory battery beyond 3 to 4 years MAX.
Factory type replacement Interstate MTP-91

 

will it handle the extra load of 600Wrms 750 peak? thanks, chris

 

See my post here. Replace your battery now before it leaves you stranded.

 

Battery is not the issue here - it is the alternator.
You should not pull more than about 40%-45% of alternator output.

I believe ours are 120amp - so you should be "ok" (right at the edge)
At idle you are going to dim.

 

this is while driving, you can see it going 40 and up, and probably under those speeds as well, I would assume. I have a friend that is a manager of a firestone, if I need to have anything changed out. I would assume a discount as well. I just need to know where to start, to remedy this. Can they test the alternator while it is in the car? I haven't really looked at the engine componets very good yet. And I just looked, it is the original battery. thanks, chris

 

I tested the battery, and it read as follows, granted I only had the stero up for a minute or two.
at rest, with car off:12.42
when started: 14.46
lowest reading during a bass song, 11.5-13.6
Now I'm confused??????????????? chris

 

Turn down the stereo - you are going to have serious hearing loss.

 

A new, higher capacity battery can help. But at 11.5v, you will see headlights dim. A higher amp output alternator can help also. Regardless of alt output or battery capacity, sometimes the surge just can't be helped when a large sudden load is put on the electrical system.

James

 

I haven't had the car on since fri, which leads me to believe, the battery is good for now. I just played a bass song, to get the strongest drop. I know that the battery will eventually crap out, it is a chrysler battery, that is probably 5 years old. Would a capacitor help for now? until I have problems with the battery. And 70 GT6, you definately can't listen to it loud for very long. I have had subs for 16 years, and receantly had my hearing checked very good results. But this is totally different than any other system I have ever had. I know when to turn it down, it doesn't take long. chris

 

Sorry I can't help with the capacitor idea. I have not dealt with them.

James

 

A fully charged battery should read 12.4 volts before you start it. When running it should be 14.4 if charging properly. If you see 11.5 volts your alternator is not supplying enough current, your battery is suppling what the alternator cannot. The only purpose of the battery is to start the car. Once you start the car, you should be able to disconnect the battery and it should run fine. If you see anything under 12.4 with the car running your battery is discharging, which should never happen. Making it likely it would not start next time.

Capacitors can supply very short bursts of current, instantaneous current on the big bass hits. Many of the sound show cars have multiple batteries, capacitors and a very high capacity alternators.

 

Yes it should, but you should never run your car without a battery connected to the charging system. The alternator will go to full charge or 'full field' and may cause failure to it. If the alternator is unable to read battery voltage, it will put everything it has trying to charge a battery that is not there.

James

 

I've tried to tell you, if you don't want to trust me then do a google search for anyone with a real competition vehicle and see how many capacitors they run. Caps are nothing more than a ploy to take your money. If you're really convinced you need one and want to waste your money, pm me and i'll sell you the one i have sitting in my closet. It was given to me, looks like a NOS bottle, I think 1 farad.

Plain and simple, get a new battery. It's time to do it anyway. Your voltage should not be dropping to 11.x with what you're running. More than likely the stock battery simply cannot discharge quickly eough to cover the amp's draw. New battery, then see where you are.

 

I don't doubt you, I just want to get what will fix the problem. Do I really need to go with an optima, or just a replacement, that has more cranking amps. Definately no disrespect. I just have never had this problem before, especially since our cars idle so low. chris

 

The battery depends 90% on you. Optimas will last a very long time, will provide a lot of current and they just look so damn pretty. They are also very ok with being completely discharged.

Personally I'd just grab a high quality replacement. I personally like my everstart maxx just fine, just make sure whatever you get will fit and has as much amperage as possible. I didn't go with an optima because a) i'm cheap as hell, b) i never run my system hard enough to really drain the battery. A dimming here and there is simply showing that the battery is being drawn upon, i never turn my system up that loud.

At this point there's no reason to guess and check with fixes but your stock battery will be dying soon, so replace it before it's needed. On top of this do the big 3 upgrade. It needs to be done anyway and won't hurt your car (can actually improve the running condition of it if the stock wiring isn't the best). You can easily do this yourself but if you aren't comfortable i'm sure a shop will do it and overcharge you(just being honest, this shouldn't cost more than like $20 of labor).


I'm not worried about disrespect I just do not want to see you waste money on a cap as they are the single largest myth in car audio. If you really want one, go on to a car audio forum classified and people will be practically giving them away.




On another note, you have me very worried about the charging system on the xfire as i will be running a very large very power hungry amp to my frontstage so I may end up throwing more money at electrical upgrades than I'd like.

 

I really want the optima, The place that installed the system, can get them, but offers the exact same kind of yellow top in a different brand, for 170. Can I get to all of the wires to upgrade with the big three? Realistically what size wire do I need. I might just be used to my cobra with 4:10 gears, but I am surprised how low this car idles, and the lower rpm's during normal driving. If the alternator puts out 120amps, at 2200rpm, I would almost have to manually shift to keep the rpms up enough. So far now I'm on borrowed time, until after christmas, unless the battery dies sooner. Then I will tell my wife, I need to do it right the first time, and get the optima. chris

 

I can get the large yellow top here at costco for about $170 so i'm not sure that's a very good deal?

I haven't looked at my engine bay to do the big three, i'll probably be undertaking that this weekend/next week if i can get access to some 1/0 locally. I use 1/0 because there's no reason not to. The wire is kind of expensive but so is filling up the gas tank.

your amp is not pulling full load all the time, so your alternator should be more than sufficient. I find it more than hard to believe that you need to upgrade your alt with what you're running. If that's truly the case, it's because there's something already wrong with your system.

 

all I know is that it gets very loud, and you can actually feel it in your chest, if listening to something with a lot of bass.