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Alternator or battery?


thedon

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I've had a squeal from a belt occasionally for a month or so, sometimes immediately after start, sometimes 5 mins later, and only lasting a few seconds. This morning the car wouldn't crank over enough to start.

 

So my first suspect is the alternator, given the sqealing belt, but the battery is 3 years old so could be past its best. Voltage on the dash has always been good though.

 

Are there any tests to tell whether I need a new battery or alternator?

 

Thanks,

Howard

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What's the battery voltage showing once the engine is running? Anything less than 13.5 means the alternator isn't doing it thing sadly. Chances are if the alternator has been weak for a while, it will have been asking the battery to do too much causing it to also fail.

Edited by davey_83
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Thanks for the replies.

 

I can't start the car, but the battery voltage was 11.05V before I started charging. The charger light went from red (uncharged) to green (supposedly charged) in 5 minutes. I left it charging for 30 mins and the voltage is now 12.76V.

 

Does that suggest a knackered battery? As you say, davey, the alternator may have caused the battery to fail, although if the battery was faulty already would that make the alternator work harder, possibly causing the belt sqeal?

 

May be clutching at straws here...

 

No, there wasn't any frost this morning. Coll but not cold (~5C)

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I've tested across the battery with the engine running: 14.5V at idle (1,200 RPM) which drops to 14.4V on load (lights, wipers, rear heated screen) - both within the 14.2 - 14.7V ideal range I think. Does that suggest a good alternator?

 

One observation: the positive lead does grip the battery terminal tightly, and can't be tightened any more. Poor contact

 

(and/or belt tension less than optimal, as you say, Tricky-Dicky).

 

But would really like to know if the voltage range when running, means the alternator itself is still OK - that's an expensive fix.

Edited by thedon
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Although I've heard of batteries on the Zed lasting for 8,9 and even 10 years they usually expire after 3-4 years.....I'm on my 3rd in 9 years.

 

 

Pete

 

That's due to lack of use Pete ! Haha. I'm still on my original battery of 10 years !

 

Quite true, lack of use will shorten the life of the battery.

 

2009, Original Battery Failed

2014 Replacement Battery Failed.

 

The original battery fail can be put down to weeks of the car standing around and the fact that it stood in a car showroom for 13 months before I bought it. I presume that it wasn't started in the showroom and that people were getting in and out of it, switching things on and off...

 

Pete

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Although I've heard of batteries on the Zed lasting for 8,9 and even 10 years they usually expire after 3-4 years.....I'm on my 3rd in 9 years.

 

 

Pete

 

I've just replaced mine, looked original. Car was registered Nov 2014, so if it was the OEM one then it managed just over 11 years.

It was drained by me being an idiot and leaving my interior light on for several days after playing about setting up my headunit. So I suspect that I could have charged it up, but I wasn't going to take the risk of getting stranded over winter.

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  • 3 months later...

A big thumbs up for Halfords - the old battery (a HCB005) had a 4 year warranty and was 3 years and 9 months old. They tested it and replaced it without a quibble. Even fitted it for me. Result :thumbs:

 

So did this fix your belt squeal issue?

Edited by DarmoZ
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For over a month now, I'm getting loud constant squeal from the belt which lasts 6-8 seconds immediately after I start the engine. I notice the belt squeal stops as soon as the volt reading reaches around 14v (which can take 6-8 seconds on a cold start) The Squeal happens on non cold starts too if left for more than 15 mins, although it's a not as bad / long then.

 

I have replaced the Battery with a brand new Optima Red top. The engine cranks into life instantly now, but the Squeal issue described above is still the same.

 

So this leads me to think it could be Alternator? or something else (loose belt). The belts were changed with brand new gates belts back in September 2015.

 

FYI in May 2015 i installed a new car audio system running a total of 900w RMS.

 

Any insight or advice you can give is much appreciated.

 

Ill add a video to demonstrate

https://vimeo.com/166207333

Edited by DarmoZ
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