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The biggest problem imho is the supercharging stations required for fast charging turnarounds. Charging a 50kwh battery in an hour requires more than 50kw of po

by beat 13y ago

The biggest problem imho is the supercharging stations required for fast charging turnarounds. Charging a 50kwh battery in an hour requires more than 50kw of power. That's a very dangerous level of voltage and current (roughly the power of a good-sized radio station's antenna), enough to kill from a distance if the slightest thing goes wrong. Maybe we'll have really safe, highly standardized supercharging stations. I hope so. But it's a Hard Problem. edit: The next-gen Tesla supercharger stations will be 120kw. I don't think those can be free forever, although they're free to premium-paying Tesla customers now.

revelation 13y ago
Power isn't really an indicator of how dangerous something is. You can kill someone on a watt. This is a solved problem, and the 120kW stations are already deployed throughout the country, without any reports of electrocutions.
- walshemj 13y ago
  And they are made safe (like electric traction on railways) by not letting the general public any where near them.
niels_olson 13y ago
Former ship's electrical officer here. We transfer 1000x that much energy to vehicles (ships) from stations (pierside "hotel" power) all the time. Electrical transfer is far safer than transfering the same amount of energy in chemical form (e.g. gasoline) and letting any lunatic walk up to publicly accessible nozzles and point them whereever they want with or without a lit cigarette. * charging leaves zero risk of explosive residue * it's ridiculously easy to apply interlocks at every step of the transfer. * the exact rate and requirement of energy transfer is very easily calculated and monitored and self-balancing. Ancillary variables like temperature and thermal expansion are equally cheap and easy to measure with very high precision. * At scale, the marginal cost of solar power gets really close to free. I have plenty of neighbors who are getting rebate checks from the local utility instead of paying them. * Energy density remains the biggest hurdle, but it's already provably good enough. The pricepoint is high only because of the small scale of production and the high-end stuff (leather seats, etc) wrapped around it.
walshemj 13y ago
yeah the effect of a fueling accident with EV's at the voltage and amperage used in those charging stations is going to be serious.

by beat 13y ago

revelation 13y ago

Power isn't really an indicator of how dangerous something is. You can kill someone on a watt. This is a solved problem, and the 120kW stations are already deployed throughout the country, without any reports of electrocutions.

walshemj 13y ago
And they are made safe (like electric traction on railways) by not letting the general public any where near them.

niels_olson 13y ago

Former ship's electrical officer here. We transfer 1000x that much energy to vehicles (ships) from stations (pierside "hotel" power) all the time. Electrical transfer is far safer than transfering the same amount of energy in chemical form (e.g. gasoline) and letting any lunatic walk up to publicly accessible nozzles and point them whereever they want with or without a lit cigarette. * charging leaves zero risk of explosive residue * it's ridiculously easy to apply interlocks at every step of the transfer. * the exact rate and requirement of energy transfer is very easily calculated and monitored and self-balancing. Ancillary variables like temperature and thermal expansion are equally cheap and easy to measure with very high precision. * At scale, the marginal cost of solar power gets really close to free. I have plenty of neighbors who are getting rebate checks from the local utility instead of paying them. * Energy density remains the biggest hurdle, but it's already provably good enough. The pricepoint is high only because of the small scale of production and the high-end stuff (leather seats, etc) wrapped around it.

walshemj 13y ago

yeah the effect of a fueling accident with EV's at the voltage and amperage used in those charging stations is going to be serious.