I'm looking to replace my 2009 Audi A4 2.0l TDi which I have owned for the last 13 years. I would like to replace it with another Audi approved A4 35 tfsi, but clearly over the last 13 yrs there has been a significant change in the technology. Firstly it now seems that you can no longer buy an A4 with a manual gearbox, unless you can find a good used 2020 model.
However, the main concern is that all the 2020 on A4's are now mild hybrid or MHEV's that use a separate 12v lithium ion battery, which raises a lot of concern, see attached photo which shows the lithium ion battery to the right of the std AGM battery encased in an aluminium enclosure.
Firstly there is only a 3yr warranty on this battery, so clearly Audi themselves do not have any confidence as to it's long term life or use and if you were to purchase a 2020 model that warranty would have expired and therefore, like any battery it will deteriorate and could fail at any time beyond that time period with no cover.
The cost to replace the lithium ion battery, 4K0915101, is a current staggering £762 plus fitting and set up so possibly up to £1K? This is for a MHEV system that at best may save 5/10% on fuel so a quick calculation shows that potentially the replacement cost of this battery, certainly in my case, could be 2 to 3 the cost of any fuel saving, madness!
Is there anybody here who has any real time experience of these MHEV models and/or could enlighten as to the likely real time life of these 12v lithium ion batteries? A std AGM battery can usually last 8 to 10 yrs.
Further, can anybody advise as to what happens if/when this battery fails or it's charge falls to a level that it can no longer provide the necessary power? Will all the normal car functions still work and operate and what functions will/would be lost if the lithium ion battery is no longer operational? Could you in fact run without this battery?
Any advice would be greatly appreciated as none of the sales people or service manages I have spoken to have a clue.