johnlocke wrote:The real problem is not what size the battery needs to be but rather how long will the battery last! If you could guarantee the the battery capacity for the life of the car, then you could just buy the size that suits your needs. But the reality of it is that the Nissan battery degrades with age and a 30 KWH mi battery is going to be good for maybe 40-50 miles after 5-6 years. You need to buy a 60 KWH battery if you want a 100 mi range in 5-6 years. ICE vehicles don't have this problem, their gas tanks never get smaller and gas milage declines only slightly as they age. Tesla seems to do much better with their batteries. Tesla may have a better technology or battery cooling solution but Nissan batteries have a lousy track record and capacity loss is a fact of life. I can live with a 30 KWH battery but not a 20 KWH. As far as the added weight of a larger battery goes, it wouldn't be much different than adding a couple of passengers.
The real question is can anyone other than Tesla build a decent battery that will last the life of the car?
Having lived with a 5-capacity-bar remaining LEAF, 26 miles to LBW, my perspective has changed. Every day those batteries are one day closer to death, even in a Tesla. So unless you're driving your 60kWh battery 200 miles a day, you've left excess battery capacity wasted. I know there are people who have long commutes, but for the vast majority, I'd be surprised if it was more than 50 miles per day.
And yes, that 60kWh battery might be down to your essential 100 mile range in 5-6 years, but you are closing in on the end of life for that pack, because now you're at the point where the weak cells will start to fail. And one weak cell essentially destroys the usability of the entire pack. Then you're looking at replacing 60kWh of batteries, and if the economics don't make sense for a 5-year-old LEAF with 24kWh, how much will it make sense for a 5-year-old LEAF with 60kWh? Or, at a certain number of years, even a Tesla, as other things will start wearing out over time and distance.
Bob Wilson, (IIRC), back on the Prius forum, used to be a big advocate of 120V charging, and if his vision was implemented, there would be dozens of 120V charging outlets for people to use while they're at work, essentially giving them another 1kWh of battery range every hour. Or, your 50 mile round trip is now two trips of 25 miles, easily done with under 10kWh of battery. Even a 100 mile round trip is possible as two 50 mile trips, with recharging at work, although you'd need a bit more than a 10kWh battery. Such accommodations are possible, as there are people with a Volt getting +500 mpg. And their little engine will be able to withstand years of relatively light duty much better and offset the need for 20 or 40kWh of batteries, thus making it a very economical choice. And replacing 10kWh of batteries is a much easier decision than putting 60kWh into a 10-year-old vehicle.
Put another way, yes it is great to not buy gasoline, I love that aspect too, but it would be better if five other guys and myself just bought a few gallons per year.