2 ms·

800V is a cost saving measure too. 800V lets them have all the HV conductors within the car half the thickness. Back in 2015, it didn't make sense because EV'

800V is a cost saving measure too. 800V lets them have all the HV conductors within the car half the thickness. Back in 2015, it didn't make sense because EV's didn't charge that fast, and battery balancing tech was still expensive (and cost scales proportional to the voltage). However, now battery balancing tech is mere cents per volt, and customers demanding fast charging means super thick (and expensive!) wires in the car and battery pack. 1000 volt MOSFETS have also become a lot cheaper (used in the motor inverters), whereas before car manufacturers were reusing 600 volt mosfets designed for other things. The only downside of higher voltages are increased insulation requirements. However, PVC insulation allows 10kV per mm, so the insulation thickness required is still tiny (although clearly you cannot use outdoor air as an insulator in either case).

tomComb 3y ago
The 800v is not relevant to “all the conductors within the car“. It is the move from 12 V to 48 V that allows them to reduce the thickness of all the wires within the car. That’s what the cybertruck introduced.
- londons_explore 3y ago
  true - it's only relevant to high voltage high current conductors. There aren't many of those - from the charge port to the battery to the motors. But those cables can easily be 10kg+ and $100+.
HankB99 3y ago
> The only downside of higher voltages are increased insulation requirements. Is there increased risk to emergency responders who might have to cut into a vehicle to rescue occupants? Or is there a possibility that deformation from an accident could result in metal parts charged to 800V? I hope things are designed to prevent that. Perhaps the insulation you mention is armored for the high voltage paths.
- ricardobeat 3y ago
  400V is already beyond dangerous, raising it won’t kill you any faster. There’s probably decreased risk because of lower current (less heat to melt things). EVs have a system that disconnects the battery mechanically when a high speed impact happens. I don’t think there have been any electrocution incidents so far?
  - HankB99 3y ago
    Good. They are designed to prevent injuries to first responders (which are nearly always exposed to some hazard when responding to a vehicle accident.) I did a search and could find no reports of injury to first responders.
- londons_explore 3y ago
  In general, any EV after an airbags-deployed accident has no high voltages in anywhere except the battery. (First responders are still advised not to go near high voltage cables, just incase the airbags did not in fact deploy)

tomComb 3y ago

The 800v is not relevant to “all the conductors within the car“. It is the move from 12 V to 48 V that allows them to reduce the thickness of all the wires within the car. That’s what the cybertruck introduced.

londons_explore 3y ago
true - it's only relevant to high voltage high current conductors. There aren't many of those - from the charge port to the battery to the motors. But those cables can easily be 10kg+ and $100+.

HankB99 3y ago

> The only downside of higher voltages are increased insulation requirements. Is there increased risk to emergency responders who might have to cut into a vehicle to rescue occupants? Or is there a possibility that deformation from an accident could result in metal parts charged to 800V? I hope things are designed to prevent that. Perhaps the insulation you mention is armored for the high voltage paths.

ricardobeat 3y ago
400V is already beyond dangerous, raising it won’t kill you any faster. There’s probably decreased risk because of lower current (less heat to melt things). EVs have a system that disconnects the battery mechanically when a high speed impact happens. I don’t think there have been any electrocution incidents so far?
- HankB99 3y ago
  Good. They are designed to prevent injuries to first responders (which are nearly always exposed to some hazard when responding to a vehicle accident.) I did a search and could find no reports of injury to first responders.
londons_explore 3y ago
In general, any EV after an airbags-deployed accident has no high voltages in anywhere except the battery. (First responders are still advised not to go near high voltage cables, just incase the airbags did not in fact deploy)