A few days ago my ek hatch wouldn't start. It started to crank but all the lights dimmed down to almost nothing and it wouldnt crank so I got stuck.

Got my battery (somewhat) tested. It had 0% charge and my mechanic said it probably had bad cells so I replaced it.

1 day later, it did it again and the battery is dead again.

A few things to know:

1. I tested the alternator myself by pulling the battery out while it was running and it didn't die. (I know this doesn't tell you a lot but it shows me it works to some capacity atleast)

2. Prior to the 2nd battery dying, my battery light on the cluster would come on until I revved the engine and would go back off.

3. Starter is starting to die (grinds, sticks once in a while)

4. It is able to be jumped.

TL;DR - Battery dies, dying starter and car won't charge.

So anyone have any idea of why it keeps dying? I think it's the alternator not keeping up but want more opinions before I throw parts at it.

 

Update: it tested 12v flat when car was off and after I tried (and failed) to start it, it read 11.75.

 

Can anyone say if they think it's the alternator or something else?

 

Check grounds, check alternator fuse? Any audio systems, anything installed lately that requires a 12v or removed?

 

The easiest way to check your charge system is with a voltmeter, set it to 20v and check the battery with the engine off should have 12 to 12.6v then whit the engine running check again you should see 14.0v - 14.6v.

Check the alternator belt adjustment. Any CEL? A bad ELD can do this.

 

start your car and while the motor running (at Idle) turn your a/c on high and you headlights on high beam. Than check the voltage at the battery. You should have about 13.8 volts at the battery. This normally means that you have a weak alternator or your voltage regulator is bad.