how to know alternator sucks
 

How do I know my alternator is dying??
Is it normal for a car to crank a little longer in the morning?
When an alternator goes bad, is it a gradual thing or does it take time?
Will I be able to start the car if the alternator is bad?

Your battery won't charge as quickly. You won't notice until one day your battery light comes on and/or your car dies because the battery runs out of power.
How much longer? A tiny bit longer is semi-normal because the fuel pressure is low from the car sitting overnight and if you don't let the fuel pump prime before you crank the engine it'll take a little longer than normal. This is because the fuel pump priming is what restores your fuel pressure to normal before you start the car.
Well since both things you just said mean the same thing, yes and yes. It happens over time. The alternator doesn't just go straight from perfectly charging to being a dead unit. However, you will likely not notice that it's going bad until it is completely dead.
As long as the battery has enough power left, the car will start and run. Whenever the alternator isn't working, the battery will not charge and eventually the battery will die and thus the engine will stop running due to having no spark.


Get your alternator tested for free at a local auto parts store. Simultaneously have the battery tested too, for peace of mind.

Does the battery light ever turn ON when driving?

Is your battery losing charge?

At night, do the the headlights brighten and dim with high versus low engine rpm?

AutoZone will test the alternator and battery free of charge.

If you have a multimeter, click here for some basic battery and alternator tests that you can do at home.

it would take about 3 or 4 more cranks than usual and the less gas I have it seems like the more it cranks in the morning.
Could this be a dirty gas filter?

How do I ensure the fuel pressure is normal before I start?

And no, no battery or noticeable dimming.
I am running HIDs with foglights in the front and side markers, I also have a 760 watt amp, but I am only using about 300 watts for 1 sub.

I also have a capacitor. When the car is off the voltage reads 12.5- when the car is on its about 14.5. Can i use my capacitor to determine if my alternator is bad?

And btw, Im about 62000 miles and I have no changed my spark plugs, could this attribute to it? Some people say you must change your spark plugs at 50,000, while some say 100,000.

The voltages you mention seem fine.

If you turn ON the high beam headlights and/or the AMP, what is the voltage across the + and - battery terminals with the engine idling?

your battery is the first that will be affected...

the voltage reading on my capacitor when the engine is on and the hi beams are on with the amp on reads 14.50

when i had the lights and amp on without the engine on, it read 11.90

With the engine idling, do the tests with versus without the high beams ON and measure voltage readings across the + and - battery posts.

If my alternator dies can I still start the car to drive it to get it fixed?
Would I need to jumpstart the battery?

err... i already answered that question