3 ms·

I'm not convinced you need battery swap stations for personal vehicles. The Nissan Leaf has a 500 VDC, 125A quick charge connector, which allows 80% charge of

by jnw2 16y ago

I'm not convinced you need battery swap stations for personal vehicles. The Nissan Leaf has a 500 VDC, 125A quick charge connector, which allows 80% charge of its ~23 kWH battery in a half hour. If you have a similar wattage charging option in a car with a 200+ mile range battery, it may turn out that the time that you will spend for lunch/restroom breaks in a typical 500 mile day of driving will be enough to recharge your battery enough, assuming you start the day with the battery topped off, and all of the restaurants and rest stops have charging stations. (But I suspect the restaurants will see early adoption of charging stations as a way to attract customers/advertise their business.) The trucking industry may well benefit from swap stations, though. The Tesla Roadster is something like 1/4 or 1/3 battery by weight. The entire tractor of a typical tractor trailer rig is probably a bit less than 1/4 of the total rig by weight, and the tractor can't be 100% battery. This will probably translate to a somewhat shorter range. On the other hand, at 60 MPH, wind resistance is probably what consumes most of the energy, and that is not strictly proportional to the weight as you scale up from personal automobile to tractor trailer.

metamemetics 16y ago
So 3 factors shape this market: batterycell tech, charging station tech, vehicle tech. The outcome depends on the rate these 3 develop relative to one another. Perhaps we could graph and predict if we had enough data? Perhaps charging station tech advances the quickest. A business produces commercial chargers and markets them to trendy coffee shops with strip mall parking (that are likely to have "green" customers) or perhaps to non-munincipally owned parking garages in urban areas. And another startup develops and markets commercial chargers for households with garages. Capitalizing on a decentralization trend (computers in every home) has great business potential. But the venture risk might be too high due and corresponding probability of success too low for this particular paradigm to take hold. Battery swapping for trucking has the advantage of being a smaller, easier to target market. But the disadvantage of less electric vehicle tech.
- jnw2 16y ago
  I'm not aware of any of the battery powered cars that have been announced being set up for battery swap. Meanwhile, AFAIK everyone has agreed on a standard AC charging connector good for 120/240 V, with the connector itself being good up to about 90A (it looks like Tesla is using it with a 50A rectifier, and Nissan 30A). Nissan's 80% quick charge in 30 minutes connector probably isn't quite high enough wattage to 80% charge a 53 kWH battery pack (as is found in the Tesla Roadster) in 30 minutes, and I think that 80% in 30 minutes may be the magic cutoff for claiming the $5000 California tax credit for buying one of these things, which leads to the question of whether Tesla will have an incentive to get quick chargers introduced which will be incompatible with the initial version of the Leaf. (As a practical matter, I think if these chargers max out at 500 VDC at 125A, that's probably good enough for road trips, though higher wattage might be nice.)

by jnw2 16y ago

metamemetics 16y ago

So 3 factors shape this market: batterycell tech, charging station tech, vehicle tech. The outcome depends on the rate these 3 develop relative to one another. Perhaps we could graph and predict if we had enough data? Perhaps charging station tech advances the quickest. A business produces commercial chargers and markets them to trendy coffee shops with strip mall parking (that are likely to have "green" customers) or perhaps to non-munincipally owned parking garages in urban areas. And another startup develops and markets commercial chargers for households with garages. Capitalizing on a decentralization trend (computers in every home) has great business potential. But the venture risk might be too high due and corresponding probability of success too low for this particular paradigm to take hold. Battery swapping for trucking has the advantage of being a smaller, easier to target market. But the disadvantage of less electric vehicle tech.

jnw2 16y ago
I'm not aware of any of the battery powered cars that have been announced being set up for battery swap. Meanwhile, AFAIK everyone has agreed on a standard AC charging connector good for 120/240 V, with the connector itself being good up to about 90A (it looks like Tesla is using it with a 50A rectifier, and Nissan 30A). Nissan's 80% quick charge in 30 minutes connector probably isn't quite high enough wattage to 80% charge a 53 kWH battery pack (as is found in the Tesla Roadster) in 30 minutes, and I think that 80% in 30 minutes may be the magic cutoff for claiming the $5000 California tax credit for buying one of these things, which leads to the question of whether Tesla will have an incentive to get quick chargers introduced which will be incompatible with the initial version of the Leaf. (As a practical matter, I think if these chargers max out at 500 VDC at 125A, that's probably good enough for road trips, though higher wattage might be nice.)