In recent test of a German suto club they found out that it‘s cheaper/ more effective to charger faster. You loose a lot of energy if you load slow over hours.

This energy is taken by the electricity of the car. So, while charging the car is on and takes some Watts/h. There are just a few brands that habe decoupled the charger circuit from the overall electric circuit of the car.

Can’t find the article now, but I think charging a PHEV through a standard power plug had about 20% energy lost. It was clearly visible that a charger is a good choice.

Did that account for battery lifetime, because if not, that could offset efficiency gains as fast charging degrades batteries.

I‘m not sure if fast charging degrades batteries. Just read somewhere an article stating that fast charging initially - first charge - boosts the overall capacity of the batterie due to chemical reactions that do not occur that long at anodes.

The issue with fast charging was the thermal management - it’s getting to hot. This is managed by good battery management and a different packaging of cells nowadays. I think fast charging isn’t an issue anymore. Can’t provide you a link or such, it’s what I gathered through serveral podcasts.