4 ms·

EV chargers and cars are already up to 800 volts, to charge a 100 kWh pack in 5 minutes you need 1.2 megawatts which is 1500 amps. Chargers and batteries might

EV chargers and cars are already up to 800 volts, to charge a 100 kWh pack in 5 minutes you need 1.2 megawatts which is 1500 amps. Chargers and batteries might go up to 1000v but don’t think there are plans to go beyond that at this point.

bryanlarsen 5y ago
The proposed Megawatt Charging System for class 6-8 trucks supports up to 3000A and 1500V.
- SigmundA 5y ago
  I stand corrected, I thought HPCVC was 1000v at 3000 amps for 3 megawatts. However it looks to be 1500v at 2000amps to do 3MW.
  - bryanlarsen 5y ago
    So did i until I looked it up. perhaps it changed recently.
rektide 5y ago
It actually would be pretty brilliant to put a 4~20kV+ SiC buck converter at the end of a cable, drop down to target voltage at the end, given how vicious power losses in a cable are & how bloody efficient SiC buck converters are. Still, getting enough output current is going to be hard. Even 750A (10 minute charge) is going to be rough. GeneSic makes some 3.3kV to247 mosfets that can do 200a, about $300 a pop on mouser. And even at better than the best efficiency that charger head would require really good active cooling, probably water cooled. Still i like the idea of staying ultra high voltage till the very end.
- rini17 5y ago
  End of the cable isn't the best place, you will still need a connector capable to handle gazillion amps and also solid hunks of copper inside car to connect it to battery. Better to integrate it directly into battery packs.
  - rektide 5y ago
    Fully agreed. Just seems less likely. There's a chicken & egg/which comes first problem. I believe a lot of cars dont even have buck converters? That they rely on the charger to ramp/control voltage? Even if they do include converters, it'd be super expensive to go from a 1kV to a 4kV or 15kV buck converter. Having ultra high voltage capable chargers that can power most cars seems like a necessary first start.

bryanlarsen 5y ago

The proposed Megawatt Charging System for class 6-8 trucks supports up to 3000A and 1500V.

SigmundA 5y ago
I stand corrected, I thought HPCVC was 1000v at 3000 amps for 3 megawatts. However it looks to be 1500v at 2000amps to do 3MW.
- bryanlarsen 5y ago
  So did i until I looked it up. perhaps it changed recently.

rektide 5y ago

It actually would be pretty brilliant to put a 4~20kV+ SiC buck converter at the end of a cable, drop down to target voltage at the end, given how vicious power losses in a cable are & how bloody efficient SiC buck converters are. Still, getting enough output current is going to be hard. Even 750A (10 minute charge) is going to be rough. GeneSic makes some 3.3kV to247 mosfets that can do 200a, about $300 a pop on mouser. And even at better than the best efficiency that charger head would require really good active cooling, probably water cooled. Still i like the idea of staying ultra high voltage till the very end.

rini17 5y ago
End of the cable isn't the best place, you will still need a connector capable to handle gazillion amps and also solid hunks of copper inside car to connect it to battery. Better to integrate it directly into battery packs.
- rektide 5y ago
  Fully agreed. Just seems less likely. There's a chicken & egg/which comes first problem. I believe a lot of cars dont even have buck converters? That they rely on the charger to ramp/control voltage? Even if they do include converters, it'd be super expensive to go from a 1kV to a 4kV or 15kV buck converter. Having ultra high voltage capable chargers that can power most cars seems like a necessary first start.