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It had seemed to me that if they could come up with a slide in battery back that was interchangeable, you wouldn’t own your own pack. You would merely rent a pack until you get to the next station.

That would eliminate the range problem. Of course that’s if you coild go at least 250 miles on a pack.

You may not own the battery pack, but one way or another you will be paying for it, and it ain’t cheap.

The true value and actual cost of operating these cars won’t be known until after the battery’s average life span under real world conditions is established.

” you wouldn’t own your own pack. You would merely rent a pack until you get to the next station.”

It would just about have to be that way. If not when your batteries were near the end of their useful life you would just go to a station and swap it out. If you just purchased new batteries you would not want to have it replaced with an old one.

I’ve seen a demonstration of quick swap batteries...and I immediately saw some major flaws. For starters, the demonstration took the car into a two sided ‘shelter’, so the equipment could be inside. This shelter setup would nearly double the footprint of a typical gas station...not an easy feat, in urban areas where land is valuable.

But beyond that - think about how many batteries this would be, in an imaginary world where electric car use was scaled up to a point to make a gas station viable. Remember, the station makes little on fuel, so its really a matter of how many people can get cycled through to buy chips. So, a full scale station may need to average 480 customers in a day (8 pumps x 2 sides x 3 customers per side an hour x 10 hours peak usage)....and I think that’s conservative. So, to account for the ‘churn’ of batteries, and the fact that it takes several hours to charge, you will likely need an inventory of 2.5 per customer...or 1,200 batteries. Now battery replacement costs are estimated between $8k-$12k...using $10k, that’s a $12 million investment in batteries, just to get off the ground. And unlike fuel costs, you don’t get this back right away. People are going to expect a ‘charge’ for less than $10, in line with the cost of electricity. So, the battery (which can only be used once in two days, costs out in 5.5 years...right about time to buy a new one.

But where do you store 1,200 batteries? The footprint just got bigger. And how do you charge 480 batteries every night...50kwh x 480 batteries = 24,000 kwh. That is one very large array of transformers.

Too many downsides.

It had seemed to me that if they could come up with a slide in battery back that was interchangeable, you wouldn’t own your own pack. You would merely rent a pack until you get to the next station.

It would be nice if something like the propane-tank-exchange model could work with batteries. Unfortunately, while propane tanks are largely fungible, batteries aren't (there isn't enough of a value difference between tanks which are in perfect shape and those which are a little beat up to encourage many people to keep good tanks for themselves and refill them while they exchange crummy ones in the hope of getting better ones; the values of batteries, by contrast, decline considerably with use). I don't know how one could effectively prevent people from hoarding the good batteries they receive from exchanges while turning in crummy ones, except by adding a substantial "big brother" tracking infrastructure.

Battery technologies are improving, and it's possible that some sort of exchange system might one day become practical. Even if it does, though, I would think it might be good for a car to have multiple batteries and use circuitry to discharge one battery at a time during most driving conditions [so that when a vehicle had been driven about half its range, one could swap out half the batteries].