Battery change

[Johnno]

my 2014 A3 8VA 2.0 tdi looks like it needs a new battery. 2.24v at rest (alternator charging at 14.5v). 
If I install a new battery myself will I create issues with coding, warning lights etc? I don’t have access to vcds.

[RoyC]

15 minutes ago, Johnno said:

my 2014 A3 8VA 2.0 tdi looks like it needs a new battery. 2.24v at rest (alternator charging at 14.5v). 
If I install a new battery myself will I create issues with coding, warning lights etc? I don’t have access to vcds.

I changed my 110 Ah battery without coding it with no problems and it wasn't even the same make.

When I enquired to Ross Tech, they said "it's been over twelve months since you changed it so it's re coded itself by now"

[Johnno]

Thanks Roy

[Magnet]

Hello John,

Thanks for joining and seeking advice.

First things first:- a simple battery voltage measurement using a multimeter is of little use in assessing the battery’s efficiency. This needs to be carried out with far more sophisticated equipment which tests the battery under load conditions. 
For 2.24v I guess that’s a typo for 12.24v. - but still meaningless. 
Alternator output at 14.5v seems reasonable. 
OK, so you have decided to treat the car to anew battery - great. 
I my book, I buy once and wisely and buy batteries with a minimum of 5 year warranties - usually Varta/Bosch, although I also heard good reports about Excide and Yuasa. I always buy on line at best prices, delivered to the door. eBay is usually my first port of call. I’ve used Battery Megastore, Tayna and others - no connection with any of them.

Need to code? I would have thought certainly yes on your 2014 car. As I understand it, Halfords can fit and code, so it’s worth getting a quote even though their prices are generally higher. Simple bit of economics - compare on-line price for quality battery of your choice + coding at independent, with Halfords quote.

Kind regards,

Gareth.

[Johnno]

Many thanks Gareth, the voltage should have indeed been 12.24 not 2.24…

[Paul JA]

Hi all, I'm new to this forum and Audi ownership so hello..

Assuming all Audis are much of a muchness electrics wise; I am at this same stage I think with my A7.

I replaced the original Varta Battery with an identical spec Bosch (which I believe is even made in the same factory) I bought battery from eurocar parts after error messages regarding failed stopstart and Adaptive cruise not working this was initially intermittent only on cold wet mornings, I'd stop the car and restart and all would be fine.

Well this progressively got worse until sometimes the car wouldn't start at all and I'd need to jump start it. This didn't fit in with my lifestyle and so I got a new battery pretty convinced that was what the issue was. Put new battery in and after a few errors messages and restarts it seemed fine, well until the next morning, it just drained overnight to 12.3v, took it back thinking I'd got a dodgy battery, got another new bosch, but checked before installing this time it was fully charged, it was showing a healthy 12.9v and fitted it today eventually, but recoded using VCDS. I'm now keeping a close eye on voltage.

MY theory is that because I didn't recode the first replacement battery the energy management system spat the dummy and drained it, well that's what I'm hoping because I've just shelled out £500 in total for what might not be the problem..

Any thoughts on this from anyone?

[Stevey Y]

17 minutes ago, Paul JA said:

Hi all, I'm new to this forum and Audi ownership so hello..

Assuming all Audis are much of a muchness electrics wise; I am at this same stage I think with my A7.

I replaced the original Varta Battery with an identical spec Bosch (which I believe is even made in the same factory) I bought battery from eurocar parts after error messages regarding failed stopstart and Adaptive cruise not working this was initially intermittent only on cold wet mornings, I'd stop the car and restart and all would be fine.

Well this progressively got worse until sometimes the car wouldn't start at all and I'd need to jump start it. This didn't fit in with my lifestyle and so I got a new battery pretty convinced that was what the issue was. Put new battery in and after a few errors messages and restarts it seemed fine, well until the next morning, it just drained overnight to 12.3v, took it back thinking I'd got a dodgy battery, got another new bosch, but checked before installing this time it was fully charged, it was showing a healthy 12.9v and fitted it today eventually, but recoded using VCDS. I'm now keeping a close eye on voltage.

MY theory is that because I didn't recode the first replacement battery the energy management system spat the dummy and drained it, well that's what I'm hoping because I've just shelled out £500 in total for what might not be the problem..

Any thoughts on this from anyone?

Hi if you don't recode a battery the BEM module will carry on charging the new battery at the same rate as the knackered battery effectively cooking it internaly.

Steve.

[Johnno]

Thanks Steve, I’ll fit a new battery then get an independent to do the recoding as previously recommended.

Johnno

[RoyC]

11 hours ago, Stevey Y said:

Hi if you don't recode a battery the BEM module will carry on charging the new battery at the same rate as the knackered battery effectively cooking it internaly.

Steve.

According to RossTech, it will eventually recognize the new battery without coding.

[Magnet]

Many thanks Roy, but I think I would leave that topic open to further debate with the latest generations of BCM vehicles. 
Kind regards,

Gareth. 

 

[Stevey Y]

On 10/8/2022 at 8:45 AM, RoyC said:

According to RossTech, it will eventually recognize the new battery without coding.

Hi roy the amount of unrecognised batteries I have come across is breathtaking, I personally got through three new batteries on one of my Mondeos before I learned of the battery counter reset function, fortunately my supplier was very accommodating as I was spending about three grand a year with him otherwise I might not have been so lucky, there are only so many DUFF batteries in circulation.

Steve

[RoyC]

33 minutes ago, Stevey Y said:

Hi roy the amount of unrecognised batteries I have come across is breathtaking

My original battery was a Moll 110Ah, it lasted for 11 years, I changed it for a Varta 110 Ah battery.

I hope this one lasts me for 11 years.

[Stevey Y]

3 minutes ago, RoyC said:

My original battery was a Moll 110Ah, it lasted for 11 years, I changed it for a Varta 110 Ah battery.

I hope this one lasts me for 11 years.

Well Roy if you are only driving six miles or so to the shops it probably will, if you do a lot more milage daily thats where the problems begin with the lack of coding especially if the car is some six years newer than yours and the electrics are totally different.

Steve.

[RoyC]

17 minutes ago, Stevey Y said:

if you are only driving six miles or so to the shops it probably will,

Haha.

I had my MOT on Monday, it passed ok.

I did 600 miles since my last MOT and 100 of those were done on the hottest day.

[Paul JA]

I am still struggling to get my A7 working.

So when I said I'd "recoded" for the battery what I did was simply change the last digit of the serial number of the original Varta on vcds,  as the replacement battery is an identical spec Bosch, my understanding is that the code doesn't really matter, the onboard computer accepts the different number regardless of what it is and adjusts itself accordingly (ie adjusts it management for a new battery).

Is this a correct? and if so is there anything else I need to do through vcds? Are there any other pitfalls I need to avoid because I've already done the above and the 2nd new battery didn't hold its charge so I took it out to recharge, its now fully charged and holding a steady 13.01v all day but just dropped to 13.00v whilst not connected to anything, is that an acceptable drop?.

I carried out a parasitic check on as many fuses as I could (except for a strip of about 5 in the boot which were inaccessable, but relate to the handbrake, rear boot and a few other circuits), and found no issues. So I'm scratching my head now trying to work out what is going on?

When the engine is running there's around 14.5v showing, so this indicates alternator is fine.

Would there be any benefit to disconnecting the battery completely for 30mins or so to clear any lingering electrical gremlins?

Any input at all would be greatly appreciated as I'm losing the will to live here 😕 

Thanks,

Paul.

[Stevey Y]

On 10/9/2022 at 7:01 PM, Paul JA said:

I am still struggling to get my A7 working.

So when I said I'd "recoded" for the battery what I did was simply change the last digit of the serial number of the original Varta on vcds,  as the replacement battery is an identical spec Bosch, my understanding is that the code doesn't really matter, the onboard computer accepts the different number regardless of what it is and adjusts itself accordingly (ie adjusts it management for a new battery).

Is this a correct? and if so is there anything else I need to do through vcds? Are there any other pitfalls I need to avoid because I've already done the above and the 2nd new battery didn't hold its charge so I took it out to recharge, its now fully charged and holding a steady 13.01v all day but just dropped to 13.00v whilst not connected to anything, is that an acceptable drop?.

I carried out a parasitic check on as many fuses as I could (except for a strip of about 5 in the boot which were inaccessable, but relate to the handbrake, rear boot and a few other circuits), and found no issues. So I'm scratching my head now trying to work out what is going on?

When the engine is running there's around 14.5v showing, so this indicates alternator is fine.

Would there be any benefit to disconnecting the battery completely for 30mins or so to clear any lingering electrical gremlins?

Any input at all would be greatly appreciated as I'm losing the will to live here 😕 

Thanks,

Paul.

Hi you are supposed to change the last two numbers of the original serial number and yes the BEM accepts that regardless of brand, 0.1 of a volt is acceptable over a few hours its such a small drop, in the car it will drop to 11.5 volts on a cold night until you get it started and it quickly recovers to over 12 volts is your alternator charging check done at the battery or from the alternator itself.

Steve.

[Paul JA]

15 hours ago, Stevey Y said:

Hi you are supposed to change the last two numbers of the original serial number and yes the BEM accepts that regardless of brand, 0.1 of a volt is acceptable over a few hours its such a small drop, in the car it will drop to 11.5 volts on a cold night until you get it started and it quickly recovers to over 12 volts is your alternator charging check done at the battery or from the alternator itself.

Steve.

Thanks for that Steve, i just checked the alternator at the jump start points under the bonnet (battery is buried under spare wheel in boot). From what you're saying could it be that the battery hasn't successfully recoded then? Even if it hasn't recoded properly it still should start and run etc for at least a while shouldn't it? One of the error messages i get now at ignition switch on is gearbox malfunction (but its the red one to put car into park not the infamous yellow error which is associated with coolant corrosion into plug) what i am wondering though is if the relay that causes the red message is faulty? Possibly caused by the battery issue? Dont know if that's realistic. But either way im sure the fix is something simple, its only after a few battery swaps that the red malfunction stays, it initially flagged when new battery went in but went away after a few ignition on and offs and car would then start fine, but this doesn't work any more, have i fried something during battery changes?