A word about battery “power” and “energy“: Batteries store energy and supply power. It’s that simple.

But in casual conversation both words are tossed around to mean just about the same thing. Here is a primer to help keep your powers and energies straight. Warning: you’ll exercise your brain in this post, so read on at your own risk.

Electrical Power and Energy

First let’s look at units of measurement and how to convert from one unit to another.

In physics, power is strength; and energy is how long the power keeps going or, simply, energy equals power times time. Power and energy are both units useful to describing the performance and capability of batteries. Power is expressed in watts (W) or kilowatts (kW, or 1,000 W) and energy is expressed watt-hours (Wh) or kilowatt-hours (kWh, or 1,000 Wh).

To help explain power and energy in context, here’s an illustration. The San Diego Gas & Electric company (SDG&E) provides power to my home in San Diego and on my electric bill I am usually charged between $.13 and $.15/kWh of energy used. For comparison, typical amounts charged for electric energy in the U.S. range from about $.02 to $.20 per kWh with a surcharge if the power exceeds a threshold level. The national average is reportedly about $.08/kWh. The City of San Francisco pays about $.024/kWh because they own the hydroelectric dam. And Disneyland pays the City of Anaheim about $.04/kWh in the middle of the night when power demands are low.

So that’s how we quantify electrical power and energy. To compare energy from batteries with other sources of energy (natural gas or gasoline, for example), we need to know how to express energy in these fuels.

Energy in Fuels

Fuel combustion chemists like to use energy units of calories (cal) and British Thermal Units (Btus). Natural gas (CH4) is sold by the Btu and liquid fuels are sold by the gallon (or liter) with a specification of Btus per gallon. Again SDG&E provides my gas in San Diego and on my gas bill the average charge is about $.88/therm, where a therm is equal to 100,000 Btus, which is a little less than the energy content of a gallon of gasoline (about 114,100 Btus). To relate natural gas and electricity, 1 kWh = 3,414 Btus or 0.034 therms and 1 therm = 29.3 kWh.

Are you confused yet? Then forget what you just read above. Here’s a summary:

• 1 therm = 100,000 Btus
• 1 gallon of gasoline = 114,100 Btus
• 1 kWh = 3,414 Btus or 0.034 therms
• 1 therm = 29.3 KWh

Feeling smart yet? Then here’s a question: which is cheaper for me to use, my gas (natural gas) or my electricity? As you might expect, the answer is: My gas is cheaper (at $.03/kWh), because most of my electricity is generated by burning that same natural gas to convert to electricity and there are always energy losses in the process.

Energy of a Moving Car

Car designers like to talk about power and gallons of gasoline rather than energy. They like to use units of horsepower (Hp) where 1 Hp = 746 W. The basic energy content of gasoline is 114,100 Btus or 33.4 kWh before conversion to mechanical energy (by burning in an engine). Because of engine efficiency losses and other factors, less than 1/3 of the fuel energy is actually available as mechanical energy at the engine output with the rest being lost as heat energy.

The energy of a moving car can be calculated using the formula below. The letter x is used as the multiplication sign.

Energy = (Weight/64) x (Speed)²
where Weight is the weight of the car and Speed is its speed at a given time.

As you can probably guess, we’re really looking at a supply and demand situation. On the supply side we have energy provided by the fuel (gasoline energy through the engine or battery energy through the electric drive motor). On the demand side we have the car with a certain mass/weight required to go at a certain speed. As mentioned above, there is always efficiency or loss of energy involved when converting from the energy supply to what the car demands.

So knowing the energy of the moving car and how long it took to get to that speed, and the energy of the battery or gasoline engine expended to get there, we can start to understand the energy efficiencies of the car’s propulsion and the acceptable performance provided by the available power level.

To keep this analysis simple and easy to understand, I have ignored various other elements that need to be considered such as discussion on the weight and speed as related to the units of power (kW or Hp) and energy (KWh or Hph). However, to play in the intelligent bantering about of power and energy in transportation and vehicle efficiency issues requires a ready reference book of conversion factors between units and a reliable associate to check the calculations. (Even the most experienced professional can occasionally be caught forgetting that a pound force = 32 x pound mass.) I sometimes use the Internet and reliable websites for a quick source of reference conversions.

Using Batteries to Power the Cars

I hope you now have good background basics on gasoline and battery power and energy, and their relationship as applied to all kinds of vehicles, including cars. With the proper relationship and conversion factors in place, we can begin analyzing and comparing gasoline and battery electricity in plug-in and hybrid vehicles.

The next step is an exciting one. We’ll discuss how batteries, as the primary energy source, are put in cars and look at characteristics that determine range, operating cost, and battery replacement.

Converting Fossil Fuel Energy to Battery Energy: Understanding Your Electric Car is a post from: CleanCarTalk

It’s all about buzz, so here’s another interesting one. A Youtube video has surfaced for a week now, describing a fast charge concept by Awesome Mobility to allow electric vehicles (EVs) to recharge quickly and affordably.

Awesome Mobility claims to have designed a recharging system that can charge your EV in the time it takes to do your shopping. According to the video, which has no source nor a referenced website, Awesome Mobility “has developed a specially constructed fast charging module that is optimized for public scale application of fast charging and electric driving. The basic module is designed to withstand the harsh environments it will be exposed due to the weather, vandalism and heavy duty of every day life. The simple exterior look modular design allows for future interior technical hardware and software improvements. Combined with the increase in use of electric vehicles, the need for fast charging units will increase hence production will get cheaper from economies of scale. The time of charging using Awesome Mobility Recharge Unit is much quicker than regular charging.”

The recharging system claims to have solved a major problem of consumer adoption of EVs by allowing trips beyond typical current EV range of about 150 miles. With fast charging, drivers merely have to pull in to recharging stations much like refueling your internal combustion-engined cars, charge up the batteries, pay for the charge, and continue on their trips.

Below is the video by Awesome Mobility for the faculty Industrial Design at the TUDelft, Holland, showing the fast charging concept.

http://www.youtube.com/watch?v=9-4vnNL7dzk

The video claims, “all the freedom that you’re accustomed to from your petrol vehicle is now easily achievable in an electric one.” It’s possible that we’ll get there eventually but the near-term scenario and technology may be more limiting at best. At the most basic level, fast charging of battery packs requires reliable battery heat management system, large cables and reliable contacts. Heat is always a serious enemy of fast charging. Additionally electromagnetic interference will need to be understood and designed for.

But assuming heat and other technical issues have been worked out for all components (batteries, cabling, hardware, software, management system design, etc.), the solution offered here is still too complex to implement with any reliability and operational confidence. Sometime I wonder why they don’t keep it simple. Why add all the bells and whistles and try to sell on the wow factor, when more reliable solutions will do?

Here’s what I mean. Again assuming the technical issues of fast charging have been solved, the cool looking and interesting sounding under-vehicle recharging mechanism is just too complex! Why not just make a free-standing charging station, much like a gasoline refueling station, and recharging the car from the side like a petrol car? A driver just plugs in to charge.

The system as described not only requires a complicated charging station, but also a completely different design of car battery system that all manufacturers must follow. The complexity level increases even more when such car must provide a receptacle on the side somewhere for the owner to recharge at home, while recharging will be done from underneath during trips.

I’m a skeptic on this one. Interesting idea, but I just wish they spend their time and effort on something more realistic and worthwhile. All we want is a working and reliable infrastructure to support our new EVs. Is that too much to ask?

What’s your view on the Awesome Mobility recharging concept? Have you seen another concept that has better and more sensible design and operational considerations? Share your views and comments below.

Awesome Mobility ReCharge: Fast Charging Solution for Electric Vehicles? is a post from: CleanCarTalk

A new study indicated, among other trends, that 21% of Europeans said they would buy a car from Apple, while 48% would buy a car from BMW.

Okay now let’s put things in context. According to a BusinessWeek article “Luxury Buyers Ready for E-Cars, Bain Says” posted by Jack Ewing on January 27, 2009, the survey by consultant Bain & Co. of Munich, Germany included 4,000 people from eight countries, including the U.S., China, Japan and Germany. General finding is that high-income buyers are ready to buy electric cars as a second vehicle. Now this is no surprise since affluent buyers don’t need basic transportation and can afford a second car, be it a Ferrari or a Tesla. What’s more interesting though is the fact that those surveyed said they are ready to buy electric cars.

It is Tesla’s strategy to build an electric car for the high-end market first. Then with experience and volume, roll out more affordable sedans for the mass. It makes a lot of sense for a company which has not produced an automobile before. But what does this really do to the industry?

According to the article, the study seems to indicate a major shift in traditional car manufacturers mentality that actually forces them to go slowly with new electric-powered vehicles. This is because as the internal combustion engines, transmissions and other conventional fossil fuel-related components are removed from the automobiles, as in the case of hybrids, plug-in hybrids and all-electric cars, the less there is to differentiate between car brands. As Mr. Ewing wrote, “Electric motors are much less complicated to build than internal combustion engines and require only a simple gearbox … The qualities that have sold BMWs, Lexus and Mercedes won’t be as unique anymore.”

What’s left is unique design, which can still give you a strong competitive edge. This means we’ll probably see more collaborations between car manufacturers and non-automobile companies in the future. And when you have the Swiss watch manufacturer Swatch choosing Daimler-Benz to build the Swatch Mercedes ART, or smart as we know it, an Apple car may not be that far-fetched.

What’s your take on this? Share your opinions by leaving a comment below.

Only the Affluent Can Afford Electric Cars Today, and One in Five Would Buy Car from Apple – Yes That Apple (AAPL) is a post from: CleanCarTalk

I was thinking the other day. What did it take for us to make the switch from VHS tapes to DVDs? and now from DVDs to Blu-ray Discs? Or from cassette tapes to CDs? and from analog to digital TVs? Or to expand the horizon a little bit more, from a multitude of things we use everyday to something else that are much better? What about the hybrids, plug-in hybrids or electric cars?

Sure there have to be debates from all corners from inside and outside the industry, plus pros and cons evaluations, cost-benefit comparisons, expert testimonies, product reviews and customer trials and feedback. No new product or technology can escape this brutal process. And it is really one of the best ways to validate a product’s merit and worth in the marketplace.

While a number of new products mentioned above are still in transition, in the end, whichever come out on top would invariably share some common characteristics with previous market “winners”. They all enjoy the commitment and push from the manufacturers (or a consortium of manufacturers) with a little bit of federal mandates sprinkled in, or any combination thereof. Without these two factors in one form or another, one can’t imagine any new product or technology coming to market.

Consumers are not a stupid bunch. But they will buy when new products are available that will work as advertised, improve their lives, and bring great feelings to the owners at the same time. The fact is marketing and sales cannot bring to market something that the manufacturers won’t build, or the government won’t mandate and support. So there you have it. It’s very simple: if we don’t force people to change and switch to clean, low-emission vehicles, they’ll just continue to do what they’re most familiar and comfortable with – driving cars powered by petroleum-based energy. Forcing people? I know, I know, this sounds un-American, but look around you. We’re already doing it. My personal view is, where appropriate and with proper regulation, it’s ok.

By the way, let’s get back to the hi-def TVs. How did we all switch to hi-def TVs? Well the new technology will give us the obvious benefits of increased flexibility and capacity, higher quality in images and sound, more programming choices, etc. But at the same time it will force consumers to shell out more of their hard-earned money to buy new TV sets and programmings. By the time it’s all said and done it will have cost us many many dollars. But guess what, there was a law and then there was a plan. And the product is good, so we pay up and enjoy it.

Hmm, maybe we can do the same with those clean car technologies? Just have a plan to phase out the old technologies. Novel idea, I know.

Want to Get Cleaner Cars on the Road? Just Yank the Old Car Out of Their Hands! is a post from: CleanCarTalk