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tonybelding · 08-10-2007, 01:41 PM

A couple of things to note about batteries. . .

I've actually read that Li-ion prices have been dropping about 8% per year, rather than 6%. If it follows that trend, then the replacement cost for a Roadster's ESS would be about $12,000. However, I put no faith in historical trends as a means to predict future prices.

As always, it will depend on supply and demand. I think it's likely that demand will surge first (after Li-ion begin appearing in hybrids), which will mean prices stay high for a while, and then some years later demand will catch up (as new manufacturing plants come online) and the price will plummet. Eventually the Li-ion cells in a Roadster might settle as low as $2000 for OEMs. It won't happen in time to benefit Blue Star, though. It might happen in time for Tesla's Model 5 or Model 6. (Magenta Star? Burnt Sienna Star?)

I think Tesla should take a hard look at how short a range might be acceptable in a less expensive, mass-market car. If you accept lower range, then you can get by with a smaller battery pack, and then all kinds of benefits come from that. You save cost on the batteries themselves, and you also reduce the weight of the vehicle. A lighter vehicle can then perform better and also be more efficient.

I'm very intrigued by the fast-charging system that Phoenix are experimenting with. If you have an electric car that can go 100 miles and can recharge in 10 minutes, and if the fast-charging stations are available in enough places where you travel (which I know is a big IF), that could become pretty practical. Reduced battery capacity makes it easier to design a fast-charging station, it could make them less expensive, which in turn would make it practical to install the stations more widely.

Tesla have laid out a vision of someday being able to go 500 miles on a single charge, which for most of us (certainly for me) is about as far as we'd ever want to drive in one day. It's an appealing vision, but I just want everyone to understand how far away today's battery technology is from achieving that. It would take at least a 150% improvement in Li-ion energy density, plus you'd still be looking at a very expensive car made from exotic, lightweight materials -- like an aluminum frame and carbon-fiber body, for example. And for most of us, for the vast majority of the driving we do which is *not* long cross-country trips, about 80% of that expensive battery pack would be dead weight.

08-10-2007, 01:41 PM	#8 (permalink)
tonybelding Super Moderator Join Date: Aug 2006 Posts: 863	Batteries A couple of things to note about batteries. . . I've actually read that Li-ion prices have been dropping about 8% per year, rather than 6%. If it follows that trend, then the replacement cost for a Roadster's ESS would be about $12,000. However, I put no faith in historical trends as a means to predict future prices. As always, it will depend on supply and demand. I think it's likely that demand will surge first (after Li-ion begin appearing in hybrids), which will mean prices stay high for a while, and then some years later demand will catch up (as new manufacturing plants come online) and the price will plummet. Eventually the Li-ion cells in a Roadster might settle as low as $2000 for OEMs. It won't happen in time to benefit Blue Star, though. It might happen in time for Tesla's Model 5 or Model 6. (Magenta Star? Burnt Sienna Star?) I think Tesla should take a hard look at how short a range might be acceptable in a less expensive, mass-market car. If you accept lower range, then you can get by with a smaller battery pack, and then all kinds of benefits come from that. You save cost on the batteries themselves, and you also reduce the weight of the vehicle. A lighter vehicle can then perform better and also be more efficient. I'm very intrigued by the fast-charging system that Phoenix are experimenting with. If you have an electric car that can go 100 miles and can recharge in 10 minutes, and if the fast-charging stations are available in enough places where you travel (which I know is a big IF), that could become pretty practical. Reduced battery capacity makes it easier to design a fast-charging station, it could make them less expensive, which in turn would make it practical to install the stations more widely. Tesla have laid out a vision of someday being able to go 500 miles on a single charge, which for most of us (certainly for me) is about as far as we'd ever want to drive in one day. It's an appealing vision, but I just want everyone to understand how far away today's battery technology is from achieving that. It would take at least a 150% improvement in Li-ion energy density, plus you'd still be looking at a very expensive car made from exotic, lightweight materials -- like an aluminum frame and carbon-fiber body, for example. And for most of us, for the vast majority of the driving we do which is not long cross-country trips, about 80% of that expensive battery pack would be dead weight.