A year ago I had a replacement AGM battery fitted to my 14 plate Superb 11 as the original was on its way out.  The garage fitting it told me that all the vehicle settings were stored on the hard drive of the ECU and, following start-up, these would be reloaded.  However, since then I've been told that this should have been electronically initialised so that the ecu knows that this is a new battery and the system should charge it as such.  Evidently if this is not done the vehicle will assume it's still the original - failing battery - and the charging both when driving from the alternator and also when recharging from a battery charger, will be regulated accordingly,  Interesting this as the new battery will not hold a charge even when fully charged with a so called intelligent charger. Is this so and if this is the case, is the battery damaged or can it be saved?

 

I'd be really grateful for some input here.

It should have been re coded , what you were told was hogwash.

The battery has been being undercharged constantly as a consequence.

It is impossible to say if it can be recovered but you could certainly try. Get yourself  a CTEK charger with an agm recon mode.

Thank you superbdreams. That's what I thought might be the case.  I have a sophisticated "Intelligent Charger" with an AGM setting and a repair mode.  If I get back the capacity lost to undercharging, how do I get the system to recognise this as a new battery?

1 hour ago, Samphire said:

Thank you superbdreams. That's what I thought might be the case.  I have a sophisticated "Intelligent Charger" with an AGM setting and a repair mode.  If I get back the capacity lost to undercharging, how do I get the system to recognise this as a new battery?

You will need VAG specific diagnostics to code it in. If you don't have anything yourself, have a look here:

 

I honestly would be tempted to go back to the garage that fitted the battery armed with this knowledge and see if they can provide anything towards the costs. The battery will likely have at least a 2 year warranty I would have thought. Some even have up to a 5 year warranty.

 

If they're selling and fitting AGM batteries they should know that the car needs coding accordingly. This isn't just specific to VAG cars but all cars with start stop.

 

The car needs to be told the new battery is installed and what capacity etc it has.

Hi Phil-E,

Thanks for coning back on this one and that would be good advice.  Unfortunately however, I bought the battery online from a well known supplier and had it fitted locally.  The company concerned have videos on their site showing how to correctly fit a replacement battery.  However, these videos make no mention of registering the new battery following installation.  I might well go back to them and see whether they will offer a credit.

I certainly would.

 

They should known the product they are selling.

 

Even just a disclamer underneath that "This battery may require programming/coding" or something.

 

The worst they say is no and you've tried.

 

But also the place that fitted it should know too.