05 4.2 V8 Petrol Battery

[ulfilias]

Hi There,

I'm contemplating getting a new battery for the Audi. The existing one is OK, though a couple of weeks of low use and short driving and it's worth putting a charger on it and as such I think it's getting low and weak.

I've also a Jeep 4.0 Grand Cherokee that if i don't use for a few days the battery is low - I modified it AGES ago to take a bigger battery, which is either old A8 or Jag (Varta 3D0 915 105 G)

However the one currently in the A8 (4.2, V8, D3 2005 PF) is odd MF Profi Start red and black thing. 60044 12V 100Ah 810A - has another code RA 531 835 - might be German?

Any ideas what i need and where's good these days ???

Ta,
Lee