Has My Alternator Died?

[dan-0]

Hey guys

I have taken my cluster and dash accessories ouut and have not used the car in a few days. Using a multimeter:

• My battery is sitting on about 11.92v turned off.
  
• I cannot start the car, it just makes a ticking sound under the bonnet.
  
• If I connect my car to another car running the battery sits on about 13.8v.
  
• It will start properly but when I disconnect the other battery the car dies??
  

Any ideas?

[t_revz]

Could be battery or alternator. But Im leaning towards battery. If you can use a charger on your battery and retest. Also try testing voltage not running then turn on headlights and see If it drops right down

[jjman]

wouldnt the easiest way to test this be to turn off the car that your jumping it from?

that way if it keeps running its the battery. If it stops its ur alternator?

[89CAL]

Get a second person and check the battery voltage while cranking, if it drops below 9V I think it is then it usually means your battery is gone.

It sounds like battery at the moment but.

[t_revz]

wouldnt the easiest way to test this be to turn off the car that your jumping it from?

that way if it keeps running its the battery. If it stops its ur alternator?

He already did this and it died. It should keep running if it's the alternator until the battery is depleted so sounds like a battery to me

[89CAL]

He already did this and it died. It should keep running if it's the alternator until the battery is depleted so sounds like a battery to me

No. From his post he hasn't checked the cranking voltage of the car, only the static voltage

Checking the cranking voltage tells alot of the story.

[t_revz]

My last post wasn't directed at yours Cal. I agree with your suggestion however a starter that Is clicking can be hard to get a reading as the multimeter usually won't keep up with the varying voltage. Plus if the battery is flat it will read low even though the battery might be fine. But more things Op tests the better:)

[89CAL]

My last post wasn't directed at yours Cal. I agree with your suggestion however a starter that Is clicking can be hard to get a reading as the multimeter usually won't keep up with the varying voltage. Plus if the battery is flat it will read low even though the battery might be fine. But more things Op tests the better:)

Haha wow sorry man. Thought you quoted me for some reason.

No idea what happened there :S

[Tai1or Made]

Check the terminals for cracks.

[89CAL]

Actually thats a fair point. Check your earths as well for good contact with the Chassis. You can use your multimeter to check the resistance from your battery negative to the body.

[HR32GTS 4DOOR]

Check the terminals for cracks.

+1 when you try and start it do the terminals get really hot.

take the terminals off the battery, you will probably find they are corroded on the inside if so clean them or get new ones.

[dan-0]

I disconnected my cluster, stereo, dash accessories etc, would that have anything to do with it?

[dan-0]

Hey guys

I bit the bullet and bought a new Century battery. Started up first go and runs great. I guess the alternator is fine!!

[t_revz]

Good stuff

[Moodles2]

I've flattened my battery so many times (sealed lead acid type) by leaving my lights on while parked, I always keep a charger in my boot. I've found I need at least 12.4V (12.6V ideally) at the battery terminals for the car to start, anything lower and there is no chance of the starter to even turn once. 11.92V there is absolutely no chance, even my motorbike wouldn't start with that much voltage.

[t_revz]

I've flattened my battery so many times (sealed lead acid type) by leaving my lights on while parked, I always keep a charger in my boot. I've found I need at least 12.4V (12.6V ideally) at the battery terminals for the car to start, anything lower and there is no chance of the starter to even turn once. 11.92V there is absolutely no chance, even my motorbike wouldn't start with that much voltage.

For the last yr before pulling mine off the road the battery had a dead cell and sat at 10v started every time. About 9v was the absolute limit. However I run 0 gauge battery cables everywhere.

[Moodles2]

I'm suprised you would even get dash lights, I know I don't with 10v

[t_revz]

Had dash lights even when cranking at around 8v. Think I got away with it cos every cylinder was so low on compression.

[89CAL]

Should easily still get dash lights with 10v. You may have a wiring issue (high resistance somewhere)

[HR32GTS 4DOOR]

Usually when a battery has been completely flattened a few times, you won't be able to pull as many amps through it even if it has 12 or so volts. my old battery which was rooted wouldn't start the car at 12 volts the new one will start it at 10.