Thursday, January 17, 2013

Apollo's electric car analysis

A few cost figures that Aronsson gives for his electrical equipment for a fuel cell/ battery combo vehicle:

The Lead Cobalt battery cost $90 per kilowatt-hour.  You can drive about 3 miles per kilowatt-hour, so I figure for his claim of 146 miles for his Silver Volt car means that he's got about 50 kilowatt hours worth of batteries in that car.  That would figure at 50*$90 equals $4500 for the batteries in that car.

The 5 kilowatt-hour fuel cell in the videos would cost $188 per kilowatt-hour * 5 equals  $940 per unit.

He doesn't have fuel cells in his Silver Volt cars, but he would need more than 1, as 5 kilowatt-hour does not have enough power.  But what he does have in that car is a 50 horsepower rotary engine powered by gasoline.  An equivalent fuel cell in terms of power would have to be close to 10 times the 5 kilowatt-hour fuel cell.  That would be hard to put under the hood, not to mention the cost would be unnecessarily high.

What to do?

Let's say that you had 3 of these in the Silver Volt.  Thus, it could reduce the drain on the batteries to about 10 kilowatt-hours per hour, I figure.  In that case, you could drive up to 5 hours at highway speed before having to stop and recharge the batteries.  That would give about 300 mile range.  Now, if you used 3 of them, the cost would be just under $3000 dollars.  Not counting everything else you would need to support the fuel cell, the total cost including batteries, looks like about $7500, so far.

In the series of videos, he showed his Mars car concept, which was said to include just 1 of his 5 kilowatt-hour fuel cells, plus 2 of the lead cobalt batteries.  The car would have a range of just under 200 miles, he says.  I'm not clear on how that would work, and what driving conditions the Mars car could be driven in.  For example, could it be driven on the highway?   I'm a little skeptical that such an arrangement would work for highway driving.  Too much drain of the batteries and not enough fuel cell capacity to keep the batteries charged.

In comparison, the Silver Volt is a fairly large car, typical of what was driven 30 years ago.  Well, it was made 30 years ago, so that figures.  Being that it is a fairly large car, 3 kilowatt-hour fuel cells just might fit somewhere on it.  Maybe in the trunk, but that would reduce trunk space.   I think that he may have a size and weight problem.

In order to support the fuel cell with an ammonia cracker, he'd have to put that cracker in there somewhere, too.  Getting crowded.  In order to deal with that issue, he'd could just have a hydrogen tank with about a 3 kg capacity.  That should be enough for the 300 mile range, mentioned above.  The hydrogen tank would be smaller than the gas tank, saving some space.  

But solving that problem creates another.  Having a hydrogen tank would reduce the economy of the vehicle, unfortunately.  That's because putting enough hydrogen in the thing would require it to be cryogenically stored, or otherwise stored under pressure.  Doing either of these options adds to costs.  About 40% more for the fuel, but it is twice as efficient.  Thus, it may still be more fuel efficient than the gasoline version, but no longer a slam dunk.

To sum it up, it is economically feasible to do this.  However, it won't be the most elegant solution, in terms of size, weight, and economy--- therefore, it may not gain a lot of popularity.


No comments: