Dying Battery or Dying Alternator?!?
 

Only had this car for about a month and so far it's been fine (except for that rattle which got sorted), however, 3 days ago as I'm driving I notice the battery light on the dash would periodically go on for a second or two then off again for maybe 5-20 seconds.

Every time the battery light comes on the headlights dimmed and the a/c fan slowed, the battery light then goes off the headlights flash really bright, then fade for a few seconds then dim again when the dash battery light comes on again.

The battery in the car is not the right one anyway, its a 54Ah with 530CCA, for a diesel engine, but according to what I can find it should have a 60Ah 520CCA battery, but suggests an optional 70Ah 600CCA battery.

Any ideas at all? I'm really hoping it's a battery because an alternator will be pricy!

Thanks in advance :)

Without doing a proper voltage test it is difficult to say whether battery or alternator.

Given that you have recently bought the car, presumably don't know the history of the battery other than it is not the correct one and that batteries are cheaper than an alternator, I would pop a new battery on and see how it goes. If it is not the battery at least you will have a known correct battery so not wasted.

I don't think the "wrong" battery would cause the faults you describe. Perhaps a failed battery might cause problems, but it sounds more like a charging / alternator problem.

That confirms my initial thoughts, but I was hoping to save a few squid and only do what I had to :rolleyes:

Sadly I think you're probably right on this, but it looks like it's going to be a pricey fix. :(

I don't suppose you or anyone else can help with part numbers can you? I've searched online but there seems to be several that it could be and as it is my only car, I don't really want to have it out of action for a week, while I pull it out then wait for the replacement to arrive!

Are you anticipating a 54amp drain or even 70amps for an hour ?!…….and will your starter use 530 amps when cranking......your battery will deliver more but it'll fail sooner than the 600cca type.

The issue is with the alternator.

I had exactly the same symptoms on my V70 Tdi early last year. It had me scratching my head too because I didn't want to waste money on buying something that wasn't needed. In the end though the battery charge light stayed on, and checking with a multimeter at the battery there was no charge.

I panicked a bit at first because I was in France, and was going to be for several months. I need not have worried though, I checked on Ebay and found a brand new alternator in Germany for £72. It was delivered within two days Express delivery £16.84. Its the same rate for UK. This price was less than some being sold as used. If you need an alternator, maybe give them a try, they may be able to sort you one for your C70. The Ebay link is below.

https://www.ebay.co.uk/itm/Lichtmasc...TR=1#vi-ilComp

Dave.. :thumbs_up:

First make sure that your battery connections are clean and tight. Battery should be secure and not prone to moving when being driven over bumps. Inspect positive lead for possible corrosion under the cable at the battery end. Check connection at starter motor. Check Body end of earth lead. Check battery with meter and note voltage. Anything under about 12.2v after car has stood for 24 hours means flat battery. With engine running check the alternator output with a meter. Should be about 14.6 to 14.8v at about 1500rpm.
https://www.youtube.com/watch?v=_1q40V-BPQc

Teach Granny to sucks eggs? Maybe.

Unfortunately, we're once again close to starting a second page on a battery or alternator thread without knowing a single voltage figure from the problem car.

OP, help us all out.....

Sorry I can't! I don't have a voltmeter thingy I was just after some thought from people that know more than me.

But after reading people responses I'm pretty sure the alternator is the issue, so I'm off to buy a replacement!