Bleakened

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.

Bleakened

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

Bleakened

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

tony_2018

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

carlos8

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.

vfeezy

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.