I've been thinking about something along these lines too. The problem is that what you want to buy is power. So, when you exchanged a battery, you'd need to know how much power had been put into it, and how much power is left in the one you're surrendering. So, you'd need to establish(a) a secure metering system, which is beyond reasonable tampering, and(b) battery technology which would not "leak" power away, and really would deliver upwhatever had been put into it.

Incidentally, with regenerative braking and home-charging (i.e. making the meters run backwards) you'd be able to sell power back to the power companies! I guess you'd have to rent the batteries by the month to give the "power" companies any return, same as you do with welding-gas cylinders.

I agree with this idea, and have long thought the same. I am not sure I think the problem of "juice" left in the battery when it is exchanged is too serious. Could fairly easily be addressed by giving you a discount or if not, then I guess users would just take the rough with the smooth.

I don't think you're talking about a cassete size battery here. I think the battery would be heavier than anything people can carry without machines. this is not the kind of battery that your jump start, and it would need to supply tons of power. my hybrid battery is huge and it handles less than half the work. so i don't think this is going to work.

do you have any idea how big the batteries are for an electric/hybrid car?!?!?!?!?! probably the primary portion of the weight of the car!

Why fiddle about with charging batteries?! Buy a Toyota Prius hybrid - I've had one for over two years now, and it is an ideal car - no fuss, no bother; just get into it and drive!

The "cassette" Would be an assembly or three that mounts under the car. Theye would have charge/useage monitoring the charge.

When you exchange the battery in your car, you'd be exchanging it as-is, for a full battery (so if you have some charge on it, you'd be out that cost, unless they can account for the charge left in returned battery, I imagine you'd have an account of some sort).

You would have in the battery, a chip that monitors charge/discharge, in much the same way laptop computer batteries have charge monitor chips.

A problem would be the quality of the battery. You might leave behind a wrecked old battery and take away a perfect new one. Who would pay for the difference, and who would monitor it? I don't know how similar systems work (eg gas bottles, containers for articulated lorries) - is it based on trust and the notion that it all averages out eventually?

Good idea and practical from my experiences with various power packs in the military. But may I suggest some type of "solid fuel" fuel cell? I remember many years ago an Australian company building a nice little car that had a zinc/oxygen solid type cell. You simply drove into a station, pulled out a 5 pound module with the "spent" zinc and inserted a new one. Refuel time was a few seconds! If more power was needed, you could provide more modules. I believe their problem at the time was perception....no one wanted a small, environmentally friendly car!

There are usually 10 to 16 batteries in an electric car so that cassette would weigh more than an engine. The pack would only last a few hours before needing a re-charge. I don't want to 'gas up' a few times a day. Pure electric vehicles just won't be convenient unless they solve the battery problem.

Hydrogen burning cars! Hydrogen/electric hybrid... You burn hydrogen in a specially made rotary engine that doesn't have many touching parts (Pistons sliding up and down a cylinder wall). The Hydrogen engine turns an electric alternator that routs through a water (H²O) tank. The water tank is separated into two different chambers bridged by a small pipe (So that the electrons can flow through). Using the process of electrolysis you separate the H²O into two separate gasses; you possibly compress them and use the Hydrogen and Oxygen for fuel (Hydrogen and Oxygen give a powerful and clean burn, turning back into water!!). You could also use a percentage of the Oxygen for a closed cabin (when driving in areas with possible toxins). I think this would be the best way to go, seeing as water as a fuel source doesn't seem too bad at all...

A small diagram I did of my innovation. http://www.geocities.com/kensei7776/H2Oengine.JPG

I was stuck on the idea of trying to figure out how to have a power source that was cheap, and on April 19th 2002 (made myself log the date in memory because I thought I was going to make a change!!) I looked the idea up on the internet and it turned out the idea had been originally thought of by the guys who conceived traffic lights back in the 1930's.

Good concept in my opinion. Yes, I know Electrolysis is a sloooooow process, but that just means you Arc in more than one chamber.

Not a new concept, it's been researched and was under development some years ago. Logically, one would go to the same place everyone else buys gasoline, except you would go in for a battery pack change. Basically, you would own your car but lease the battery pack, just as I do now with my propane tank exchange (or my welding gas bottles). Propane tank exchanges are a sort of lease that is renewed whenever you exchange the tank (which is why exchanges are more expensive than simply having your own tank filled). My welding tank lease has a term of 3 years, and must be renewed at the end of the lease.

Battery packs would have to be modularized and standardized, of course, and you'll have to figure out how to make money doing this, but it's a good idea. I think personally I'll go with a diesel-electric hybrid minivan or midsize pickup.

I've been thinking about that too, but it depends on why you would ant to use it my dad pointed out to me that the power has to come from somewhere so if you're doing it to be an environmentalist then your effort is wasted.

Batteries for vehicles are very heavy, and often very many. But what you might be able to do is cycle out the liquid electrolyte and put in freshly charged electrolyte. A single connector could be designed to purge and fill the batteries while protecting the user from dripping or spilled acid.

Design cars so the batteries slide in and out of a compartment with the aid of a customized dolly. Changing the battery would be faster than filling a tank of gas.

The government would need to standardize the batteries, charge indicators, etc, and make it illegal to mess with them.

Battery charging stations could be anywhere there was a power source - power lines, windmills, etc. Also, no worries about leaking underground gas tanks at service stations. Even mobile battery changing trucks would be possible, for those stranded.

Had the same idea myself.

First, to all the people who mentioned the weight and size of batteries in electric vehicles: they are big and heavy because they can't be easily replaced. They have to store all the energy for the vehicle to travel over its rated range. If they could be replaced easily, then they could be smaller, see? The idea under discussion here is one way to cut down the weight and bulk.

Let's take an extreme example: a vehicle with a thirty mile range. Absolutely unacceptable! However, the battery pack is (relatively) small and light.

It would be like a chemically-fueled vehicle with a 2-liter tank. So, let's turn the problem on its head. What would it take to make a 2-liter tank acceptable?

Stopping for 10 minutes every 1/2 hour would be a drag, right? What about stopping for 30 seconds every 1/2 hour? Better. How about just slowing down every 1/2 hour, like in a car wash? Even better still. Ok, so how about not stopping at all? That's what jet fighters do. They have lousy range -- so they refuel without stopping.

So, if we could swap a small, light battery cassette without even slowing down, that would be ok, right? Regardless of the range? (Don't worry about how we're going to do that yet, I'll get to it later. I promise.) Just say, "Yes, IF you could swap a cassette without even slowing down, then batteries would be practical." Go on, say it, you know it's true.

Now, that is a big IF, but not as big as "IF you could put more power in a lighter battery pack," because that "IF" requires a breakthrough. Worse, it requires a breakthrough in an area where the brightest minds have already worked for over a century. Don't hold your breath.

Swapping a cassette on-the-fly, though? That's just development -- it doesn't need any breakthroughs. Any really bright engineer could come up with something. In fact, a really bright engineer could come up with several ways to do that. It's just mechanics. We know a lot about mechanics.

In fact, it's just assembly, and we know even more about automated assembly than we do mechanics in general. I'm going to stop now, because if I start posting possible means to swap a cassette on-the-fly, people will argue with the means.

Remember I said any really bright engineer could come up with several ways to do that? Well, they will!

That's not the purpose of this post. I just want people to accept the idea that IF the means to swap cassettes on the fly could be developed, then the range of the battery is no longer the big problem.

Research: Zenn motor co. They say they will have an ultra-capacitor powered car by 2009 which will solve all of the problems associated with electric cars and charging. And is the enabling technology.

capacitors may soon be a much better idea than batteries, there is much research into them and they charge much faster http://www.utdallas.edu/news/2008/09/19-001.php