Hi All,

Suspect I have bought a duff battery but . . . . .

It a yuasa battery  YBX 9096 rated at 70Ah now 6 months old. I fitted it myself and have been unable to key the battery information into the cars electronics - I thnk i read here somewhere that it doesn't really matter - but does it?

 

the problem is left in the drive for more than a coupe of days it goes flat - mostly it will start but on a couple of occasions I needed to dig out the spare battery I keep for this purpose! I took it into Quikfit who attached a gadget and pronounced the battery just fine and also that the alternator was charging fine.

 

When it is sitting idle there is a (fully charged) GPS watch and a (fully charge) Satnav plugged in and taking power. Also, when it hasn't switched itself off, a dashcam. All up I doubt that is a much as an amp yet an alleged 70Ah battery goes flat in 48 hours

 

I'm just back from a short (10m) trip. A voltmeter (Cigarette lighter) shows 14.4 when the engine is running and 12.4 when the engine is turned off decaying slowly to 11.7. I worry that I have a capacity problem but have no idea how to test for that.

Any suggestions as to what to do next to confirm the source of the problem.

 

 

A new battery really should be coded to the car, but leaving a sat nav etc plugged in will soon drain a battery, especially on a stop/ start vehicle as the battery is never charged 100%.

20 minutes ago, RIncewindwiz said:

A voltmeter (Cigarette lighter) shows 14.4 when the engine is running and 12.4 when the engine is turned off decaying slowly to 11.7.

How slowly? A battery shouldn't decay to 11.7v quicker than a few days when off load, which suggest that there may be something drawing current.

9 minutes ago, PetrolDave said:

How slowly? A battery shouldn't decay to 11.7v quicker than a few days when off load, which suggest that there may be something drawing current.

This was a quick test I did (so not typical) to get a voltage and I just happend to notice the decay. Engine running for maybe a minute bt within 30 minutes ot the 10 mile driver I referred to

26 minutes ago, Kenny R said:

A new battery really should be coded to the car, but leaving a sat nav etc plugged in will soon drain a battery, especially on a stop/ start vehicle as the battery is never charged 100%.

Really? the SatNav is an old mobile phone and that takes very little current - the battery is only 2.Ah at 3.7v and the GPS watch even less.

31 minutes ago, Kenny R said:

A new battery really should be coded to the car, but leaving a sat nav etc plugged in will soon drain a battery, especially on a stop/ start vehicle as the battery is never charged 100%.

How do I code the battery to the car?

8 minutes ago, RIncewindwiz said:

How do I code the battery to the car?

 

Kenny: Battery does not appear to have a BEM number

Supposed to be a fit for VW battert

Have you tried scanning the QR code on the new battery for BEM information.

 

Thanks AG Falco

Good thought. Bit of a challenge as well as it is barely the size of a stamp.

Anyway the answer is not. It interprets as a string of meaningless (to me) characters as follows

3#5Q0915181H #HH02S1011#401142351#150815*DTH74185704001508155161*=

Over on https://www.q3ownersclub.co.uk/threads/replace-agm-battery.5145/   it says it is only really necessary to register the manufacturer and the Ah

so I could give that a go and see if it helps?

On 09/04/2020 at 15:33, Kenny R said:

A new battery really should be coded to the car, but leaving a sat nav etc plugged in will soon drain a battery, especially on a stop/ start vehicle as the battery is never charged 100%.

 

Sorry but I dont see any way that a battery rated at 70Ah (even half charged) can run down when it is connected to 

1. a mobile phone (satNav) on standby. It will happily st on standby for over a week in its internal 1230mah battery

2. a GPS watch (turned off, just charging the battery ) when it will run watch only for over a week on its internal battery

Remember neither of thee two devices are switched on.

 

And you think they will drain a big car battery in 36 hours? Does not make any sense to me.

 

 

@RIncewindwiz is it not the charging hardware rather than the devices themselves?

On 09/04/2020 at 20:17, RIncewindwiz said:

Over on https://www.q3ownersclub.co.uk/threads/replace-agm-battery.5145/   it says it is only really necessary to register the manufacturer and the Ah

so I could give that a go and see if it helps?

 

Right, from the top.

 

YES you should have coded the battery to the car and you are finding out the reasons why.

 

The important bits are:

TYPE (EFB AGM etc) so it knows what to charge

CAPACITY (so it knows what to charge to)

 

The Really important bit is

SERIAL NUMBER so it knows you have changed the battery and is not  stopping charging early as it has learned to do with the old battery. In reality you only need to change what is there by one digit so it sees a difference.

 

Add into this the car has regenerative charging and may not be charging all the time you are driving (which is why it needs good information)

 

Code the car for the new battery . Fully charge (or recondition) the battery using a good smart charger built for the job like a ctek.

 

You will then be fine, I doubt there is anything wrong with the battery

Surely a simple test is to disconnect the plug ins and see if the battery still goes flat.

3 hours ago, octavia5 said:

Surely a simple test is to disconnect the plug ins and see if the battery still goes flat.

Beyond dispute that the plug-ins take current. my question is why is there so little 'current' to take.

4 hours ago, flybynite said:

 

Right, from the top.

.

.

 

YES you should have coded the battery to the car and you are finding out the reasons why.

 

You will then be fine, I doubt there is anything wrong with the battery

 

Thanks

Sounds eminently sensible. Will give it a go today or tomorrow and see what happens.

Still find it staggering given that it never happened with the old battery even when it was on its death bed!!

 

2 hours ago, RIncewindwiz said:

Beyond dispute that the plug-ins take current. my question is why is there so little 'current' to take.

 

Have you overlooked the possibility that the items plugged in are malfunctioning - just suggesting to eliminate all possibilities - years in IT have taught me that nothing is always as it seems.

3 hours ago, RIncewindwiz said:

Still find it staggering given that it never happened with the old battery even when it was on its death bed!!

 

Next question is what battery did you take off? Octavias were almost universally , fitted from the factory with an EFB battery. I would imagine that is what it is coded to. There is a chance you may well have screwed up the battery with the car charging your new AGM thinking it is a failing EFB

 

Although I prefer the German-made batteries like Varta, Yuasa are generally good batteries so I would doubt it has failed by its own accord. I would still do the same, i.e. check the coding properly, then do a full recon using an AGM-capable smart charger.

 

Add to this that some battery drain can stop the BCM going to sleep. When not in use the car shuts down a lot of things after a while, things plugged in can stop this and have a larger effect than their drain alone would suggest.

To add to the confusion on this I have just received the charger I ordered and plan to plug in tomorrow.

 

So, I will do a recon charge but this should in theory make the battery into something different to what the car has learnt. Does this mean I need to code it to an identical battery but change the serial number so it thinks it's new or will the difference not be enough to warrant the coding.

 

Apologies for the hijack.

The battery is original btw on a late 2014 car so I realise it's due to be replaced soon. I have previously disabled s/s so the cells haven't seen a heavy life just a long one compared to other modern batteries as per the multitude of battery threads of late.

1 hour ago, MarkyG82 said:

or will the difference not be enough to warrant the coding.

The recon, even by the best battery charger, will not do enough to the battery to make a difference to what the BCM sees when charging the battery so coding will not help. You only need to code a new battery

Do NOT use the recon cycle on an AGM battery.

 

The 15 odd volts may damage the battery. If a ctek, just use the standard AGM charge cycle until it is fully charged.

6 hours ago, cheezemonkhai said:

Do NOT use the recon cycle on an AGM battery.

The 15 odd volts may damage the battery. If a ctek, just use the standard AGM charge cycle until it is fully charged.

 

Not quite correct, the 'recon' function will not harm an AGM battery, but it will not do it any good either, as it does not suffer from stratification that EFB batteries suffer from.

 

All batteries benefit from desulphation but that step is in the normal charge cycle

 

I am making the assumption that the batteries in question on an Octy 3 are EFB (as a good AGM is not likely to fail in that time) and will make use of a de-stratification recon.

 

Destratification recon WILL harm a GEL battery but it is unlikely to find one of those an an Octy 3

3 hours ago, flybynite said:

 

Not quite correct, the 'recon' function will not harm an AGM battery, but it will not do it any good either, as it does not suffer from stratification that EFB batteries suffer from.

 

All batteries benefit from desulphation but that step is in the normal charge cycle

 

I am making the assumption that the batteries in question on an Octy 3 are EFB (as a good AGM is not likely to fail in that time) and will make use of a de-stratification recon.

 

Destratification recon WILL harm a GEL battery but it is unlikely to find one of those an an Octy 3

I was told by a battery manufacturer that the sulphur ions being pushed off the plates can’t get away and end up instead damaging the plates.

 

They said not to use any 15v + cycles.

 

I am not a battery expert, but either way, why take that chance?

Edited 22 April, 20206 yr by cheezemonkhai

The only real need to use recon mode would be on a deep discharged battery that has been left for several days or weeks. It’s a form of mild overcharging to soften off sulphate crystals formed during discharge of the battery so they can be reabsorbed back into the electrolyte.

 

The risk of overcharging an AGM is drying out the limited moisture inside. They have a very specific moisture content which can be reduced by overcharging. This is the bit that damages the battery if it continues too long or too frequently.
 

That’s why AGM need a charging voltage limited to 14.8v to prevent drying out and long term damage.