Any issues to watch out for changing the battery?

[Woody_72]

Hi all, Just got back from Northwest VAG TECH in Runcorn where I'd taken my car because the airbag light was on. Top place, he spent a good twenty minutes with my car and reset the codes and basically said there are no real faults but the car is reporting slightly low voltage which is probably what caused the codes to set. He reset the airbag light and tested the battery and basically said the battery is borderline bad and I should look at replacing it soon and then refused to charge me saying it was a quick job - top bloke!

Anyhow, stop/start batteries are eye-wateringly expensive but the Halfords one (made by Varta, which he recommended) are £160 so I think I'm going to replace it before winter sets in. I'm quite happy replacing batteries but is there anything I need to look out for? I believe the radio isn't code based but are there any relearns or anything similar I need to be aware of? TIA!

As a a slight aside, I asked about prices for a full coolant drain and replace with G13 and he said a couple of hours labour (you need to hook it up to VCDS to open various valves to do it properly) plus the coolant, £110! So I'll definitely be back there soon!

 

[Mtailor]

Sent you a PM

 

[Mtailor]

i bought a S5 A08 Bosch AGM Car Battery 12V 70Ah Type 096 S5A08. i'll send you a PM with the link to where i bought it from. Did my research - EFB batteries are normally fitted on our cars. EFB batteries are widely used in vehicles with entry-level start-stop systems, usually without recovery of braking energy. AGM batteries (Absorbent Glass Mat) score with their high performance and durability. EFB batteries have been introduced as a lower tier option to AGM batteries in terms of performance and durability. Hope that helps

 

[Woody_72]

It does, just ordered a brand new EFB Varta for a whisker under £133 delivered . The old one's 5 years old so I guess I've had my money's worth.

 

[Mtailor]

For similar money, you could have got the AGM cell.

Better performance. Still the EFB is a good battery


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[Mtailor]

Remember the batter will need to be coded back to the car.

There is a guide somewhere on this forum.

Need to find it myself for tonight. It’s arriving!!!!


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[Big Vinny]

I bought a "Car Computer Memory Saver" off eBay. It plugs into the OBD2 diagnostic socket and allows you to connect a second 12V battery to maintain a 12V supply, so that the main car battery can be changed with out loss of memory settings etc.

It looks good although I have not used it yet. I will do so with an old motorbike battery when the need arises.

 

[black_sheep]

Battery coding info:

Via CAN:

Battery Replacement - Ross-Tech Wiki

wiki.ross-tech.com

 

[RUM4MO]

I've bought one of these Draper memory savers that plug into the OBD2 port as well, again it has now been used yet. My older Draper one that had a mains transformer was given away, I also had a Draper one that used a 9V battery. I've even bought the next size up battery tray and battery insulator for my wife's 2015 Polo 1.2TSI 110PS, but the last time I checked its battery health, it was up to that batteries quoted capacity, so all these bits might need to wait a while yet! I plan to replace that EFB with an AGM and change the battery coding, technology and capacity as well as serial number - the next size from what the Polo 1.2TSI 110PS is cheaper as it is used in more cars!

 

[Mr Pig]

Wow! A lot pf aggravation just to fit a new battery. Do you think the spot magnets in Halfords do this?

 

[Mtailor]

For ODBEleven users - this is the guide.

Battery Replacement | OBDeleven

Saw the following article here (thanks to EFF11 For the info) and below is the detail of how to code the change

obdeleven.proboards.com

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[Wastedagen]

If one was to replace the battery with exactly the same one, I take it no coding would be necessary..?

Edit: oh wait just seen... There's a serial number to add... That would more likely be different.

 

[RUM4MO]

The need to change the serial number will be mainly to force the battery management system to recognise that a new battery has been fitted, and so it will change the charging profile back to what a new battery "need" and not what the old battery was given by way of an adapted with time and battery condition charging profile, that will be all.
It has been said that if you do nothing, given time, the charge profile will eventually correct itself by adapting to suit that new battery, so changing the serial number just sorts that out as soon as you replaced the battery.
I've only ever sorted out one battery and that was in a late 2007 Audi A6 TDI, which was bought as an approved Audi fitted with an EFB - but all these A6 should have had an AGM from factory I think, anyway the "good" but all marques garage sourced a new and correct technology battery but did not change anything, which coming from a mainly dead EFB to a new AGM was probably not essential, but I changed its serial number - that car did not have a battery technology option for EFB so that sort of backs up my theory that these cars should have all been sent out with an AGM, which means that Audi main dealer was being a typical Audi scamming dealership and had swopped batteries before sale.

 

[Woody_72]

Well my shiny new Varta's arrived. It actually is an AGM battery. Really in two minds now whether to fit it and try and get it coded at the weekend or fit it Friday evening and try and get it looked at Saturday morning ...

 

[Mtailor]

I fitted mine today. It was easy enough. coding wasn;t difficult.

The car starts now - without needing a booster!

 

[Mr Pig]

.which means that Audi main dealer was being a typical Audi scamming dealership and had swopped batteries before sale.

They would do that?

 

[Woody_72]

Been Googling BEM code related stuff for hours and found that the Varta E39 AGM battery I bought is classed by Varta as the absolute direct OEM replacement battery for my car so I'm going to ask them to just increment the serial number by one when I get it coded even though the original battery is 68Ah and the new one is 70Ah. Close enough ?‍.

 

[Walone]

Been Googling BEM code related stuff for hours and found that the Varta E39 AGM battery I bought is classed by Varta as the absolute direct OEM replacement battery for my car so I'm going to ask them to just increment the serial number by one when I get it coded even though the original battery is 68Ah and the new one is 70Ah. Close enough ?‍.

If they are going to do that, they might just as well input all the necessary information in to the coding boxes. Also if your car has petrol engine then the standard battery would be EFB so the coding will not be correct for AGM.

 

[Woody_72]

It's a diesel with AGM battery and the new battery is spot-on for the job but doesn't have a BEM code and the serial and part numbers don't appear to be in quite the correct format.

 

[Walone]

It's a diesel with AGM battery and the new battery is spot-on for the job but doesn't have a BEM code and the serial and part numbers don't appear to be in quite the correct format.

That's very strange, especially from a company such as Varta.