Accessories and Power Use

I grew up in a town where the average temperature in the summer was at least 100 F (38 C).  It was a town where it was assumed that you had an air conditioner or if not at least a swimming pool.  And not having either was cause for living uncomfortably.  I also took a strong interest in car audio in middle and upper school.

The use of air conditioning and audio in automobiles definitely puts a drain on fuel consumption, but it is not as noticeable because the energy density of petroleum is so high.  But how does it affect the driver of an electric vehicle?

Air Conditioning

I was at first wary of using the air conditioner on the Smart ED.  I thought that it, like the heater would cut my range drastically.  It turns out, that in certain driving conditions, my efficiency improves.  Obviously I do not own a perpetual motion machine, but I've noticed that I tend to drive more smoothly with using the A/C.  For whatever reason, my driving manner is different when the A/C is on, than when it is off, regardless of the outside temperature.

The A/C will draw extra power from the pack, but unlike the heater the vehicle does not automatically take a reserve to cover for the cooler.  However, you will notice when you come to a stoplight that an exhaust fan will start up.  This fan is very loud and will make your car sound like an A/C unit on wheels.  This same event occurs on ICE vehicles, but the engine noise usually overpowers it.

Car Audio

Car Audio on the other hand, at least the stock head-unit, is powered by the 12V auxiliary battery.  And in turn the main pack recharges the 12V, just like the alternator in an ICE vehicle.  The stock speakers and stereo are not very good in the Smart ED, but they are better than not having a system.

I tested the audio in the vehicle when I bought it, but I didn't use it for a while either because I was thinking that it would drain the main pack.   In reality, after having used the radio, even at high volume, I have yet to experience a significant difference in the main pack range.

Conclusion

I have no cross-referenced trials to present, but I do have my own experience.  I've driven many times with the A/C on and the radio blasting, and have not noticed a gross difference in the main pack battery.  More often than not it is how I drive that determines the battery performance and longevity.

A serious hypermiler might consider the use of these accessories as detrimental to the extreme mileage possible, but I am no such person.  I already know that by driving electric, I am being much more efficient than any ICE vehicle, but a factor of at worst 2 and at best 20.

I am sure that there are some people who believe that by using the A/C or radio that they are giving up some range.  But if that range is 1 mile, I think I am willing to sacrifice it for the same of comfort and entertainment.

Regen Addiction

I have an addiction.  It's not a physical addiction, it's a mental desire to recoup the energy wasted from braking.  I am addicted to regenerative braking in electric vehicles.

Over the years I've had a few vehicles.  From a tiny Subaru GL, to a Volvo 240, to a Scion XB.  I then changed from the small car to the monster truck and traded the xB for a Chevy Tahoe and began my truck phase.  But unlike all those internal combustion engine vehicles, none of them changed my thoughts about the power source, because electric cars were just the hobby of eccentric people.

It might be reasonable to think that electric vehicle owners are on the fringe and that driving under the power of electricity doesn't actually change a person.  For an efficiency-conscious person, like myself, merely driving electric isn't the only beneficial feature.  It's the regenerative braking that I want.

I still own an internal combustion engined vehicle, and every now and again I need to drive it.  That vehicle is a Chevy Avalanche and when I bought it, I loved it for its utility.  I still love the utility of it, but now the lack of regenerative braking causes me a twinge of mental anguish.  For now there are no consumer pickup trucks that are pure electric vehicles, but there are some hybrids.

A company called Via Motors takes Chevy trucks and converts them to series-hybrid vehicles.  They buy the trucks with a V6 engine, which they bolt directly to an electric generator.  They add batteries and another motor to drive the wheels. All these additions does add about 1500 lbs of weight to the truck, but despite that, the new drive train improves the efficiency by a factor of 5. Typically these trucks get 15 MPG, with the change it improves to roughly 100 MPG.

I would gladly purchase a Via Motors VTrux in a heartbeat if I had a spare $75k.  As of this posting, the public cannot access these vehicles, but Via Motors has announced that some time in 2014 they will be making them available to non-commercial customers.

The only other alternative to my dilemma is to consider either the Chevy Volt or BMW i3.  The i3 offers an optional electric generator that will produce an additional 100 miles of range when the battery has run out of juice.  Whereas the Volt has a permanent engine that acts as a generator 95% of the time, and only on rare occasion will power the wheels in parallel with the electric motor.

The idea of regenerative braking, super energy-efficiency, and alternative power sources, isn't actually all that new, but thank goodness we're moving toward it finally.  I look forward to the day when regenerative braking is the norm.

Dual Carbon Batteries, what next?

The announcement of the Dual Carbon battery got me thinking about power storage in electric cars.  There are two lines of thinking in this area, (1) faster charging (2) greater range.  At the moment most people are concerned about the range, but charging or refueling is also a concern.

The dual carbon battery promises much and, at least supposedly, can deliver.  It should be noted here that the dual carbon battery is not all new.  Many battery chemistry types have been, in theory, possible for decades, but there was not much time spend on research.  A company called Power Japan Plus is the one to announce a functional dual carbon battery last week, that is making headlines.

Current battery technologies like Nickel-Metal Hydride (NiMH) and Lithium Iron Phosphate (LiFePHO4) have provided a solid example of what is possible with battery technology.  But there is always room for improvement.

Gasoline has ruled the automobile industry for 100 years because of it's energy capacity.  Although gasoline requires that it be burned to harness the energy, that has not slowed its use. We could have been using nuclear power to the same end, creating massive quantities of radioactive waste rather than pouring carbon monoxide into the atmosphere, but gasoline was available first.

We don't use nuclear energy as much because of its toxic waste products.  Even batteries have some toxic materials in them, until now.  However, the dual carbon battery is made of 90% recyclable materials and offers many other features that are not found in Lithium Ion batteries.   By comparison the LiFe battery does the following better than any of its predecessors...

• It doesn't get hot or explode when in operation (lithium is volatile)
• It's made of carbon, which is quite plentiful (compared to lithium which is not)
• It charges much faster than lithium, about 20x faster
• It can be recharged more times that any other battery chemistry

So Dual Carbon solves problem number one, and by chance resolves a few other issues.  It might just be the solution that arrives sooner than lithium air and in the long-run is cleaner. 

But the revelation of Lithium Air and now Dual Carbon, leads me to wonder, what's next?  Is there some super material out there that we've yet to find that will be more energy dense than gasoline, clean, fast to recharge, and recyclable?  Based on these two recent technologies, it's my guess that there is something better.

How Far Does Your Car Go?

As it stands, the Smart ForTwo Electric Drive has an EPA estimated range of 68 miles. The average U.S. driver covers about 30 miles per day.  It would seem that the electric Smart more covers this by more than double.  But in the near future, your car could go a great deal further.

It's been said that "your mileage may vary".  The EPA estimates that the Smart ForTwo ED gets between 92 and 122 miles per gallon equivalent to gasoline (MPGe).  Unlike internal combustion engine (ICE) vehicles, for EVs the low number is on the freeway, and the high number is on the street.  But the average still comes out to about 108 MPGe.  The EPA also sets a range for ICE vehicles, which on average tends to hover around 25 MPG.

How far does your car go on a full tank or battery? Does it go 250, 300, 500, 1000 miles?  The average range on a tank of gasoline tends to be between 250 and 300 miles.  Whereas the average for an EV tends to be around 100 miles. For an ICE vehicle, the range depends how many gallons of full can be carried.  The same goes for electric vehicles, but for kWh of charge.   But what if the capacity of the battery could be drastically increased, in the same space?

Currently gasoline has a strong advantage over even the battery that can hold the most charge.  In terms of charge density (Wh / kg) gasoline holds 13,000 Wh / kg.  The technology in electric cars today has a charge density of 250 Wh / kg, a ratio difference of roughly 50 to 1.  Even with the 4 to 1 ratio of better performance over ICE, EVs still can't compete.

However, there's a new technology that's being worked on in chemical labs around the world.  IBM is one company that has taken a strong interest in the idea of greatly improved battery capacity.  The new technology is called Lithium Air and promises to increase the energy density of batteries to 11,700 Wh / kg.

As noted above the Smart ForTwo ED has a range of 68 miles.  With the new Lithium Air battery, and without changing the size of the battery, the range could be increased to as much as 3,182 miles.  I currently drive about 10,000 miles per year.  At this rate I might recharge every 4 months.  The battery in the Smart ED is now 17.6 kWh, with Li-Air it would 813.1 kWh (that's 0.8 Megawatt-hours).  At current electricity prices where I live that's only $80-worth of electricity.

Check out this video that IBM created to better explain the idea of Lithium Air