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[paul8594]

Had a problem with my 3.2 53 plate estate.

Don't drive it that often so it more often than not I have to recharge battery.

The other day went off for a little drive of about 30 miles. About 18 miles in the battery light came on. Over the next couple of miles dashboard looked like a 70's disco, rev and speedo stuck and zeroed, power steering became heavy.

Managed to get it to a lay-by where I turned the engine off. Couldn't get it started so left it there and came back with spare battery.

Got it home and got a new alternator fitted. Went to friendly tyre and battery place and got existing battery checked. It was knackered

However checking the readings we were only getting 12.4v with engine running down to 12.1 with load ( xenon's and hearing )

Fitted new battery and got only 12.1 running down to 11.8 with load.

Thinking it may be lower because its a new fully charged battery went my merry way.

Driving south, going away on holiday it died again after 100 miles. Battery totally flat, even charged jump pack couldn't resurrect it.

Check everything visible all seems okay

Any ideas, please

[RobG]

new alternator fitted.

Brand new or secondhand?

[paul8594]

Brand new unipart one

[Nick W]

You're seeing battery voltage with the engine running, so you have an alternator fault. That might be the unit itself, or a connection.


Now you need a multimeter to decide what to do next.


I would check the voltage at the output stud of the alternator first; you're looking for about 14volts. If that's the case, then you need to check the wiring between the alternator and the battery. If it's only the same voltage as the battery then the alternator isn't working and it's time to have a whinge at the supplier.

[paul8594]

Thank you. Will check out

[Bigron]

Nick, sorry to argue with you, but as the battery feed goes to the starter via the alternator terminal and the car starts without issue (doesn't it?), it suggests that the wiring is sound - unless the person who fitted the alternator didn't tighten the connector adequately.
It's rare, but possible, for a new alternator to be dodgy.....

Ron.

[neil74]

It's not that long ago I fitted a recon alternator to my 3.2 estate. because one day I thought the drivebelt was looking a bit tatty so I went and bought a new belt, tensioner and waterpump thinking that i'd treat the car to some new parts. but I found out the waterpump wasn't quite the same as the original and if fitted would result in the pulley being further in towards the engine and the fixing bolts would hit the pump casing so that little exercise stopped before it started. but I thought i'll put the new belt on anyway and all went well until I got about 5 miles down the road and the alternator died on me and then when id finished that I took it for another drive only to have the oil light come on.

[Nick W]

Nick, sorry to argue with you, but as the battery feed goes to the starter via the alternator terminal and the car starts without issue (doesn't it?), it suggests that the wiring is sound - unless the person who fitted the alternator didn't tighten the connector adequately.
It's rare, but possible, for a new alternator to be dodgy.....

Ron.

This is why you diagnose with a meter, rather than just guess/hope.

[YZ250]

Having been through this myself a couple of weeks back I agree with Nick's post.  Mine was the alternator regulator so turned out a cheap enough fix but, as said, need to get a multimeter on it. 

[Kevin Wood]

Check the crimped connections to the battery terminal clamps, as these often work loose.

Failing that, some diagnosis with a multimeter, as said.

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

[terry paget]

I have known Omega alternators fail, but not completely, just output fewer amps than they should. My test is to check voltage across battery engine off (12.2 volts), start engine and at idle it should be 14.2 volts, then put on some load, all lights, flashers, rear screen heater, fans, anything else I can think of, then the voltage will fall to about 13 volts. If it falls below 12 volts the alternator is failing.

In the days of dynamos with cut outs the warning light would always advise of failure, with alternators and electronics the warning light is less reliable.

[VXL V6]

I've had three fail, two not charging at all and one overcharging. The not charging mode is far more preferable!