Anything above 77 volts is considered by electrical code as entering the lethal range, as at that point it starts to overcome the natural resistance of dry human skin.
Don't start that age old argument "it's the current" nonsense. Like saying don't go near the water, you may drown, but you take a shower or wash your hands without any concerns.
A car battery has over 600amps at 12 V, and an ignition coil has over 30,000 volts at a minute amount of available current.
We seem to manage 120V daily without too many deaths.
Europe lives daily with 220V in their appliances.
I have seen people accidently touch 125,000+V powerlines and survive (granted without their toes)
As an example of escalation, people can die at ten mph riding their bike, but nobody bats an eye at driving 70 mph on the interstate or flying at 600mph on 737.
Concern over 800V in cars is just more agenda driven propaganda.