4 ms·

They're getting mixed up, the 400-800V systems are _only_ for the motors, everything else in the car still uses low voltage. In fact, afaik every single electr

They're getting mixed up, the 400-800V systems are _only_ for the motors, everything else in the car still uses low voltage. In fact, afaik every single electric car has two separate systems. There's a high voltage system (the main battery and motor(s)) and the low voltage (almost always 12v) system, usually with a traditional lead-acid 12v battery that is charged via a DC-DC converter connected to the high voltage battery.

Kirby64 3y ago
Not true in most EVs regarding 'only the motors'. The AC/heat pump compressor is run off the HVDC, typically. Since it runs for long periods of time and consumes kilowatts, you want to run it straight off the main HV battery. Also, any vehicle that still uses resistive heating (older EVs tended to do this, Tesla included) use the HVDC for that.
Moto7451 3y ago
I’m speaking about the power planes. What they drive is irrelevant from the standpoint that higher voltage systems create safety issues that lower voltage systems do not have. No one is going to be ok with “occasionally being shocked by 48v” or “occasionally seeing arcing in their car from a high voltage system.” Running 48v to a radio is not an engineering marvel. Running it safely and reliably in an automotive environment full of vibration and weather is. If you can do that with 400v, I argue you can do it with 48v, so the secret sauce they’re sharing is less relevant than if they did this ten years ago.
- Turskarama 3y ago
  I feel like you're mixing up points now, running 48V is fine _because_ the voltage is low enough that it's unlikely to kill anyone if you mess it up. The 400V system in the meantime has a lot more care taken and limiting the systems it works on to ONLY high power systems lessens the number of things that can go wrong.

4 ms·

They're getting mixed up, the 400-800V systems are _only_ for the motors, everything else in the car still uses low voltage. In fact, afaik every single electr

by Turskarama 3y ago

Kirby64 3y ago
Not true in most EVs regarding 'only the motors'. The AC/heat pump compressor is run off the HVDC, typically. Since it runs for long periods of time and consumes kilowatts, you want to run it straight off the main HV battery. Also, any vehicle that still uses resistive heating (older EVs tended to do this, Tesla included) use the HVDC for that.
Moto7451 3y ago
I’m speaking about the power planes. What they drive is irrelevant from the standpoint that higher voltage systems create safety issues that lower voltage systems do not have. No one is going to be ok with “occasionally being shocked by 48v” or “occasionally seeing arcing in their car from a high voltage system.” Running 48v to a radio is not an engineering marvel. Running it safely and reliably in an automotive environment full of vibration and weather is. If you can do that with 400v, I argue you can do it with 48v, so the secret sauce they’re sharing is less relevant than if they did this ten years ago.
- Turskarama 3y ago
  I feel like you're mixing up points now, running 48V is fine _because_ the voltage is low enough that it's unlikely to kill anyone if you mess it up. The 400V system in the meantime has a lot more care taken and limiting the systems it works on to ONLY high power systems lessens the number of things that can go wrong.