Replace Audi A8 D3 Battery

After 11 years, my 2006 A8L Varta original battery 4E0 915 105 A 850CCA died over a few weeks and it no longer held charge. I bought a battery from Walmart EverStart Maxx H8 with 900CCA to replace it. The H8 is the same size as group 49 which is smaller than the original Varta …