2 ms·

The CCS standard supports 1000V. Furthermore charging cables are locked while charging. (The latch is on the cable for CCS, and the latch is inside the car for

by kccqzy 2y ago

The CCS standard supports 1000V. Furthermore charging cables are locked while charging. (The latch is on the cable for CCS, and the latch is inside the car for NACS.) Unless the lock mechanism is mechanically broken, it's impossible to unplug a cable that's charging.

goodcanadian 2y ago
The latch is on the car for CCS. It is only on the cable for chademo. Regardless, the main issue with high current is the cable resistance. You need very thick cables or they will melt. Higher voltage helps, but cable weight is a real issue at higher power. P.S. NACS is just CCS with a different connector.
- lazide 2y ago
  It isn’t just that higher voltage helps, higher voltage is the key factor. Heat dissipation is a factor of amperage (solely) in the wire, and higher voltage means lower amperage for a given amount of power. Literally. [https://en.m.wikipedia.org/wiki/Ohm%27s_law https://en.m.wikipedia.org/wiki/Ohm%27s_law] The challenge here is that above a certain voltage, insulation gets prohibitively difficult (and bulky), which makes solid state electronics to control and manage it also prohibitively difficult. And leakage current becomes dangerous. For example, we could run chargers at 1 million+ volts, and use standard 12 awg stranded cables to do it with very low losses (and low heat) at megawatt charging rates. But the insulation would be crazy thick (inches?) and if there was any damage or minor leakage, it would be very dramatic very quickly. Like ‘mini nuke’ type arc flashes. And because the distance you can strike an arc in air with 1 million+ volts is measured in multiple feet.
sebazzz 2y ago
Even if the lock is broken, the pilot connector of the CCS connector is longer, so it would disconnect before the DC connectors would disconnect. Similar to how the D+ and D- lines of USB-A are shorter than the VCC/GND lines.

by kccqzy 2y ago

goodcanadian 2y ago

The latch is on the car for CCS. It is only on the cable for chademo. Regardless, the main issue with high current is the cable resistance. You need very thick cables or they will melt. Higher voltage helps, but cable weight is a real issue at higher power. P.S. NACS is just CCS with a different connector.

lazide 2y ago
It isn’t just that higher voltage helps, higher voltage is the key factor. Heat dissipation is a factor of amperage (solely) in the wire, and higher voltage means lower amperage for a given amount of power. Literally. [https://en.m.wikipedia.org/wiki/Ohm%27s_law https://en.m.wikipedia.org/wiki/Ohm%27s_law] The challenge here is that above a certain voltage, insulation gets prohibitively difficult (and bulky), which makes solid state electronics to control and manage it also prohibitively difficult. And leakage current becomes dangerous. For example, we could run chargers at 1 million+ volts, and use standard 12 awg stranded cables to do it with very low losses (and low heat) at megawatt charging rates. But the insulation would be crazy thick (inches?) and if there was any damage or minor leakage, it would be very dramatic very quickly. Like ‘mini nuke’ type arc flashes. And because the distance you can strike an arc in air with 1 million+ volts is measured in multiple feet.

sebazzz 2y ago

Even if the lock is broken, the pilot connector of the CCS connector is longer, so it would disconnect before the DC connectors would disconnect. Similar to how the D+ and D- lines of USB-A are shorter than the VCC/GND lines.