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[Nick27]

hi, my car battery gone flat last night called RAC to do a jump start and the engineer advised that he suspects that alternator is faulty and is not charging up the battery. Battery was recently replaced in Dec-2012. Any ideas if  it is alternator or something else 

[tunnie]

You need to get a meter on it with the engine running, see what it reads 

[steve6367]

Can you measure battery voltage with engine running? Your looking for around 13.8v - less would indicate a charging problem potentially.

Please be very careful with battery terminals, there is a lot of energy in the battery which can be released very quickly if you short the live to ground etc

Steve

[Nick27]

Engineer checked this yesterday and the voltage was less than 13.8 it was reading between 11.9 - 12.1

[Nick27]

Does that mean it still charges but not to its max. Power... Am i able to drive around today with that faulty alternator? Will it not strand me in the middle of the road?

[flyer 0712]

If you know anyone with a meter that you just clip on to the positive battery lead that will give you the voltage coming from the alternator to the battery,,should be 13.8 ..

[steve6367]

Does that mean it still charges but not to its max. Power... Am i able to drive around today with that faulty alternator? Will it not strand me in the middle of the road?

It's not charging at all at those voltages - check wiring to alternator and / or remove it and have it looked over / replace it.

[Kevin Wood]

Bear in mind that, as the battery was flat before he got it started, it may be drawing a large current from the alternator leading to a lower then normal voltage. I would charge the battery up using a mains powered charger then go through the steps in the guide:

http://www.omegaowners.com/forum/index.php?topic=90619.0


Bear in mind that the crimps on the battery terminals often get loose. If these are getting hot or loose, than that's your problem.

Does the battery warning light come on with the ignition, then go out as the engine starts?

[Nick27]

yes the warning light does come on and does go out as normal, but yesterday before it gone flat, while i was driving the battery warning light came on for a 2 seconds and then went off. but it didn't came back until it went flat when parked outside shopping center.

i do not have a meter unfortunately to check the steps provided in the guide.

Bear in mind that, as the battery was flat before he got it started, it may be drawing a large current from the alternator leading to a lower then normal voltage. I would charge the battery up using a mains powered charger then go through the steps in the guide:

http://www.omegaowners.com/forum/index.php?topic=90619.0


Bear in mind that the crimps on the battery terminals often get loose. If these are getting hot or loose, than that's your problem.

Does the battery warning light come on with the ignition, then go out as the engine starts?

[kevinp58]

Bear in mind that, as the battery was flat before he got it started, it may be drawing a large current from the alternator leading to a lower then normal voltage. I would charge the battery up using a mains powered charger then go through the steps in the guide:

http://www.omegaowners.com/forum/index.php?topic=90619.0


Bear in mind that the crimps on the battery terminals often get loose. If these are getting hot or loose, than that's your problem.

Does the battery warning light come on with the ignition, then go out as the engine starts?

It only takes around 12v to put light out so in effect it could be out but not give a satisfactory charge if lights, radio and rear screen heater is on. 
But the only real way to check it is to take off and get checked but as Kevin says check out all the leads to and from battery and alternator to see if loose or any corrosion

[robson]

Go buy yourself a meter very cheap these days and will be useful for many jobs.

[car5car]

If your battery is dead, check your back yard. I found and installed one yesterday.
It took about 1 hour to fit it. I am not paying $100 for a battery!
http://s213.beta.photobucket.com/user/car6car/media/JbirthdayCadbattery021_zps3094051f.jpg.html

[Kevin Wood]

Go buy yourself a meter very cheap these days and will be useful for many jobs.

Yep. You can pick one up for a Fiver at Maplins. Got to be better value than replacing alternators / batteries without proper diagnosis.

[dbug]

If your battery is dead, check your back yard. I found and installed one yesterday.
It took about 1 hour to fit it. I am not paying $100 for a battery!
http://s213.beta.photobucket.com/user/car6car/media/JbirthdayCadbattery021_zps3094051f.jpg.html

  an hour to swap a battery  does that include 20+ coffee breaks 

[Seth]

Try connecting a jump lead from the battery NEGATIVE (-) post to a good earthing point on the engine (such as a manifold stud/nut).

See what the readings are thence.