Replacing Battery

[2fquick]

Hi, after an unexpected trip to hospital, the A6 stood for 4 weeks and will not crank over.

As it is 8 years old I have ordered a new battery Varta Silver / Varta Batteries / Batteries by Application

I have VCDS to recode the type & serial

Should I just disconnect the old battery and fit the new one or connect another power source to the cables to avoid and data loss?

Any advice ?

thanks

[royclark]

Hi, after an unexpected trip to hospital, the A6 stood for 4 weeks and will not crank over.

As it is 8 years old I have ordered a new battery Varta Silver / Varta Batteries / Batteries by Application

I have VCDS to recode the type & serial

Should I just disconnect the old battery and fit the new one or connect another power source to the cables to avoid and data loss?

Any advice ?

thanks

Conect a battery to the terminals under the bonet, then follow the 7th screen on this site. - Ross-Tech: VCDS Tour: Recode

[gupsterg]

Hi,

If you are replacing a 110ah battery with 110ah battery no need for recode of battery regulation module regardless of brand...

I had genuine Audi Varta 110ah changed to Bosch S5 110ah...

As battery regulation module have no Bosch part no, I just changed serial to date for fitting new one for my own reference...

I replaced my battery i) without any battery/charger underhood ii) only data loss was IIRC clock lost time & perhaps trip counter went to 0miles

ESP warning light will come on but a little drive and turns of steering left/right will solve this...

Possible related thread Link:- Whats the state of charge of your battery?

Link:- Audi A6 (4F) Battery Replacement - Ross-Tech Wiki

ATB
G

[ruggedscot]

Just a note - Dont try to change your battery using a battery charger on the terminals under the bonnet to keep voltage on your car electrics - Bad move !
As soon as you disconnect the battery the charger output will bounce about and it is this bounce that could affect damage your electrics. I have done battery replacements before using another battery connected across the jump terminals - remember use a fuse on the + lead of your additional battery just for peace of mind.
When diconnecting the lead in the boot have something ready to cover and isolate the + lead as this will be live all the time from the other battery.
Its a quick way and it saves an issues with radios and other equipment in the car being affected by the power loss during the change.

[royclark]

Just a note - Dont try to change your battery using a battery charger on the terminals under the bonnet to keep voltage on your car electrics - Bad move !
As soon as you disconnect the battery the charger output will bounce about and it is this bounce that could affect damage your electrics. I have done battery replacements before using another battery connected across the jump terminals - remember use a fuse on the + lead of your additional battery just for peace of mind.
When diconnecting the lead in the boot have something ready to cover and isolate the + lead as this will be live all the time from the other battery.
Its a quick way and it saves an issues with radios and other equipment in the car being affected by the power loss during the change.

Do you connect the other battery with jump leads to the terminals under the bonet?
What size fuse do you use on the + terminal?

[ruggedscot]

I made up a lead for this - as you are not actually starting the car or running any high power equipment - only wanting to maintain a float voltage on the system electrics Ive used an old extension lead and on the + of both ends Ive added an inline fuse holder and put in a 5 amp fuse. The reason for fusing at both ends is to ensure that any damage to the lead cuts the power - you have two potential power sources so best to provide a safety at each side. If you had a fuse at only one end and you shorted the lead at the fused end then you could have the whole length of lead burning up before you knew it. I also made the lead using 2.5mm....

[joshA6]

Hi,

If you are replacing a 110ah battery with 110ah battery no need for recode of battery regulation module regardless of brand...

I had genuine Audi Varta 110ah changed to Bosch S5 110ah...

As battery regulation module have no Bosch part no, I just changed serial to date for fitting new one for my own reference...

I replaced my battery i) without any battery/charger underhood ii) only data loss was IIRC clock lost time & perhaps trip counter went to 0miles

ESP warning light will come on but a little drive and turns of steering left/right will solve this...

Possible related thread Link:- Whats the state of charge of your battery?

Link:- Audi A6 (4F) Battery Replacement - Ross-Tech Wiki

ATB
G

X2 above. I have disconnected the battery loads of times (when retrofitting my S3 sterring wheel & airbag) and never had any problems with memory or other functions. I htnk even the date stays set if you only disconnect for a couple of minutes.

[msh]

I also have replaced battery with no loss of settings without using a separate battery as a back-up. You don't even lose radio settings.

[ruggedscot]

You may get away with it but when it does bit yer bum youll wish you had done something to stop it..... been doing car electrics for a while and find this little trick helped - used to hate fords with their key code radios and other cars were the same.... dont know how many Ive adverted but id guess enuf to make it worth while.

[gupsterg]

Just for the thread and in context of the A6 4F ... I left my battery out for days on the A6... if my memory serves me correctly other then the clock/ESP light/trip going to 0 miles I did not have to recode anything... everything worked as it should... did not do anything with VCDS ...