Should I charge to 100%?

The Zoe ZE50 uses LG Chem NCM 712 E78 cells. The VW id3 also uses E78 cells. VW recommend only charging to 80%. The Zoe battery warranty runs for 8 years or 100k miles but only applies if the battery falls below 70% state of health which is a pretty poor battery. If you want to maximise battery life you should avoid high ambient temperatures as far as possible, minimise fast charging and try to keep the battery as close to 50% charged for as much of its life as possible. If you regularly fast charge and keep it fully topped up it will still last a long time (and not trigger the Renault warranty) but not as long as if you treat it gently, as above. This has been an established and well understood characteristic of NCM Lithium cells for many years. One of the reasons 80% is often referenced is that fast chargers usually slow the charging rate considerably at this point which is a different issue - in normal home charging 80% is not a magic threshold, 70% is better, 65% better still etc but 80% is a good compromise. If you need 100% for regular long journeys then fine but your battery state of health should be expected to degrade slightly more quickly.