Ok, I've been having this new battery and alternator in the car for about a month! It runs perfectly fine, doesn't die and the lights don't dim when i press on the break! But it seems like every now and then the charge battery light comes on! Now I was wondering if I would need to go up to a larger alt but I'm not positive, because I want to beable to run an alarm, cd player wit 6-1/2s with all lights on and etc... perfectly fine? So what are some suggestions on coming about doing this? help please......

Hasan

 

Check the wireing on the alt, also check the batterys voltage off the 2 studs, at rest it should be around 12-15v.

 

If you decide to go the larger alt route let me know what you do.

If your going to get a amp with your new system though I would look into investing in a capicator

 

yeah i'm not going to go with a system for a while, i just want a plain stereo system so I can have some type of music, cuz I have nothing right now...... haha....

 

Check the voltage with the car running and your foot on the brake pedal.

The voltage should not be dropping under 13.5 volts... if it is; the alt is not putting out enough juice to charge the battery.

If it is dropping under 12.5 volts the car is running on the battery as the alt is not producing enough power to even run the car.

 

If it's just running on battery that means I should upgrade to a bigger alt?

 

well, yes and no.

If you have added considerable extra draw (such as huge amps for the sound system, or extra lights, or high power ford electric fan) and you are running low, then yes a bigger alt would be needed.

But if you are running basicly stock (maybe an aftermarket high power radio, fog lights, or CDI) and running down under 13.5 volts, then you either have a bad alt (most common), or bad wiring to the alt. Then you need to fix it, rather than upgrade it.

See the stock alts were oversized for the cars to start with. I have seen a stock S4 alt (70 amps peak) have no problems keeping up with even a 700 watt (RMS) stereo system, or adding extras such as a CDI system. The automatic response of "just upgrade the alt" is generally not needed unless considerable modifications and additional draws are added to the car. A good running stock alt will run fine in many cases.

Of course that many people have 15 year old alts that are not putting out even 50 amps peak anymore, has convinced many that they need to upgrade, when just a re-manufactured alt that is putting out the correct power is all that is really needed.

 

Thanks mark! The information you provided is highly needed...... thank you very much.....

Hasan