Audi A8 - Yuasa battery - Presumed battery failure - best make?

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Fri 18 Sep 2015 09:55
Audi A8 - Yuasa battery - Presumed battery failure - best make? - John F

Just over a year ago I bought what they said was the best battery in Halford's - a 100Ah Yuasa HSB019. After inadvertently flattening it a few weeks ago it has now twice failed to retain enough charge to start the engine. The 8 and 9 year old batteries in our other two cars have on occasion been similarly flattened and continue to be reliable.

Is there a known problem with this make?

When I return it to Halfords can I insist on a different make replacement?

I don't think the alternator is faulty as I measure 14v at idle and even charging with a modern (Halfords!) charger overnight is no good.

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Fri 18 Sep 2015 10:02
Audi A8 - Yuasa battery - Presumed battery failure - best make? - kiss (keep it simple)

Take it back to Halfords. Being flattened once and re-charged straight away shouldn't cripple it but it won't have done it any good. How long did it stay flat for? They will test it at some point to determine what killed it but doesn't it have a 3 or 4 year guarantee?

Edited by kiss (keep it simple) on 18/09/2015 at 10:02

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Fri 18 Sep 2015 11:54
Audi A8 - Yuasa battery - Presumed battery failure - best make? - steelghost

The plates will sulphate if the battery is left flat for any length of time - even a few days can significantly harm them. Some designs are more resistant to this than others, but this is a matter of degree.

As kiss asks, how long was it left flat for? How did you charge it thereafter - did you bring it back to full charge or just put enough into it to get the car started? If the latter, you may well have been driving around with a *nearly* flat battery, which is not quite as bad as leaving it flat, but is going to inflict further damage.

You mention other flat batteries - is there some set of circumstances which leads this to happen regularly?

Edited by steelghost on 18/09/2015 at 11:55

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Fri 18 Sep 2015 11:57
Audi A8 - Yuasa battery - Presumed battery failure - best make? - RT

Yuasa is generally regarded as a good brand, many will be adamant it's the best - unless Halfords give you a refund I doubt you'll find their other options as good.

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Fri 18 Sep 2015 12:36
Audi A8 - Yuasa battery - Presumed battery failure - best make? - Galaxy

I don't know why people buy batteries from Halfords; they're very expensive!

Edited by Galaxy on 18/09/2015 at 12:36

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Fri 18 Sep 2015 12:51
Audi A8 - Yuasa battery - Presumed battery failure - best make? - John F

As kiss asks, how long was it left flat for? How did you charge it thereafter - did you bring it back to full charge or just put enough into it to get the car started? If the latter, you may well have been driving around with a *nearly* flat battery, which is not quite as bad as leaving it flat, but is going to inflict further damage.

You mention other flat batteries - is there some set of circumstances which leads this to happen regularly?

I just jump-started it and assumed further driving (it has a hugely powerful 2.6Kw alternator) would charge it pretty smartish.

Not regularly; our ancient Focus battery (flattened for several days in an airport carpark after carelessly turning the lights off too far to the parking light position and not noticing!) is still fine, as is the TR7's which often doesn't turn a wheel for almost a month if the weather's bad - but I always disconnect it anyway.

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Fri 18 Sep 2015 12:58
Audi A8 - Yuasa battery - Presumed battery failure - best make? - elekie&a/c doctor
I suspect there may be nothing wrong with the battery.Modern batteries need a special smart charger to bring them back to life.This could take 2-3 days being on charge.Yuasa are a good brand and fitted to many makes as original equipment.

Edited by elekie&a/c doctor on 18/09/2015 at 12:59

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Fri 18 Sep 2015 15:21
Audi A8 - Yuasa battery - Presumed battery failure - best make? - steelghost

I'm intrigued - I know Lithium ion batteries in mobile phones etc have very sophisticated charging controllers, but I didn't know this also applied to lead acid automotive batteries?

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Fri 18 Sep 2015 15:20
Audi A8 - Yuasa battery - Presumed battery failure - best make? - steelghost

It depend then on what sort of driving you've been doing, what other electrical loads have been imposed on the battery (eg how many times the engine was started) etc etc as to whether the battery actually got a decent charge - but the fact that it failed suggests it may not have done. That 2.6Kw alternator doesn't just charge the battery - it also (potentially) has to power a lot of other electrical equipment!

Out of interest, what engine does your A8 have?

Note I'm not saying the battery was not faulty - only that the sort of incident / circumstances you describe has the potential to be very unkind to a battery, which can lead to its early demise.

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Fri 18 Sep 2015 18:56
Audi A8 - Yuasa battery - Presumed battery failure - best make? - gordonbennet

Yuasa are one of, if not the only, make to offer a full 5 year warranty on top range batteries.

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Fri 18 Sep 2015 19:23
Audi A8 - Yuasa battery - Presumed battery failure - best make? - RT

Yuasa are one of, if not the only, make to offer a full 5 year warranty on top range batteries.

Not the only - Bosch offer 5-year guarantee on S5 versions.

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Fri 18 Sep 2015 22:20
Audi A8 - Yuasa battery - Presumed battery failure - best make? - John F

Out of interest, what engine does your A8 have?

W12 (A rare SWB)

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Fri 18 Sep 2015 19:18
Audi A8 - Yuasa battery - Presumed battery failure - best make? - Wackyracer

I just jump-started it and assumed further driving (it has a hugely powerful 2.6Kw alternator) would charge it pretty smartish.

If only it was that simple we would all be driving long distances in electric vehicles.

There really is no instant battery charging, If your battery is flat your looking at a minimum of 10 hours charging using a smart charger of at least 7amp rating.

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Fri 18 Sep 2015 20:46
Audi A8 - Yuasa battery - Presumed battery failure - best make? - madf

A 100AH battery will take 4 hours running to fully recharge it by teh alternator - assuming no other electrical loads and full alternator charging.

In the real world, that is 8 hours continuous running..An A8 has an awful lot of current drawing equipment which is live ALL the time... Just starting once probably needs 10AH...

You need to fully charge it.. at least 12 hours overnight with a smart charger before you know if its dead.

I suspect you'e b####ed it due to running it with no charge for a long time.

(We have had two Yuasa batteries fitted as OEM - both died after 10 years usage..)

Edited by madf on 18/09/2015 at 20:47

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Fri 18 Sep 2015 22:31
Audi A8 - Yuasa battery - Presumed battery failure - best make? - John F

In the real world, that is 8 hours continuous running..An A8 has an awful lot of current drawing equipment which is live ALL the time... Just starting once probably needs 10AH...

You need to fully charge it.. at least 12 hours overnight with a smart charger before you know if its dead.

I suspect you'e b####ed it due to running it with no charge for a long time.

I suspect you are right. But it is a very clever car in that it shuts down unnecessary equipment if it detects battery weakness (how it does this is beyond my comprehension). However, it did get a 16hr overnight charge and a recent 50mile round trip, but doesn't seem to have made much difference. It now struggles to crank what is admittedly a lot of machinery - effectively two VR6s. I'll see what Halfords make of it next week.....

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Wed 23 Sep 2015 22:03
Audi A8 - Yuasa battery - Presumed battery failure - best make? - John F

I'll see what Halfords make of it next week.....

Exchanged without question - friendly and helpful as usual. Even fitted it for me. That's how to gain customer loyalty, methinks.

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Thu 24 Sep 2015 13:09
Audi A8 - Yuasa battery - Presumed battery failure - best make? - madf

Thanks for teh update. Glad it's fixed foc.

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