Archive for April, 2011

VW Touareg hybrid dyno chart showing power without boost

Below is a dyno chart showing power of the combustion engine alone and combined power with the hybrid motor on a VW Touareg hybrid.  The Porsche Cayenne hybrid S uses the same drivetrain in a slightly different body (same underlying chassis).

As you can see, power from the 3.0L supercharged engine is quite good.  Where the hybrid motor’s additional power really shines is at the low end.  This is due to the characteristic of a hybrid motor.  They provide maximum torque at 0 rpm which decreases as friction and other limitations rise with rpm.  Horsepower provided by the hybrid motor is more or less constant as rpm increases.

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Difference between level 1, 2, 3 in electric car battery life and heat

I recently read that the US is close to finalizing the level 3 connector for electric cars.  Which brings up the question for this article,

What is the difference between level 1, 2, and 3 electric car plug in chargers?

Long story short, level 1 is 110 volts like your common household outlet.  Level 2 is 240 volts which is what most home electric dryer run off but is usually only available in a few outlets in your home.  Level 3 is 480-500 volts and is not wired in households and is not yet standardized.

The Nissan Leaf’s fast charger is a special level 2 box that is wired to your garage and can fully charge the 24 kWh battery pack in about 8 hours.  In reality, most people won’t drain the useful life of the battery fully so they’ll really only use it a few hours at a time to top off the battery pack.

There is a dark side to fast charging: heat.  As anyone who has used a rechargeable battery fast charger knows, they come with fans to help cool the battery during charging.  Even so, fast chargers kill the batteries due to heat and the cycling.   Good aa, aaa rechargeable battery chargers should have individual circuits to account for differences between battery conditions and trickle charge at around 200 instead of 700 or higher amp.  The faster the charge, the less capacity and life you’ll get due to fast charge problems  .

Current car battery technology is no different.  The Audi Q5 and A6 hybrids come with their own dedicated air conditioning to help the battery packs stay cool.  The VW Touareg hybrid and Porsche Cayenne hybrid use nickel metal hydride batteries and use only air cooling from fans.  These are only there for regular operation, not the fast charging of a full EV.

The other problem is that houses aren’t wired for this amount of voltage.  The household outlet is 110V and they get 240V by doubling up the wires in the fusebox.  If you take off the cover panel of the average household fusebox, you’ll see 2 buses, or fuse strips, with criss crossing wires which is how they get 240V.  In addition to the household end, there’s also limitations on the service wire that runs from the utility pole to the home and upstream.  Simply put, most houses can easily add a level 2 connector but you have to go to an industrial charging station to get access to a level 3.

If you have any more questions or comments, feel free to post in the forums!

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Audi A5 e-tron quattro pictures

Here’s a gallery of the A5 e-tron quattro in cold weather testing and the unique instrument gauges of their EV.  The e-tron is Audi’s name for their electric drive vehicle model range.  If you notice the picture showing the drive components, unlike earlier etron models, there is a gasoline engine on this prototype but it doesn’t drive the car at all.  In this prototype, the gas engine is there only to power the battery – the car is still moved by the electric motors only.  Previous etron models had no combustion engine at all.

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Audi A3 e-tron specs

Wow, Audi is really rolling out their e-tron line quickly.  While this is just a prototype based off the current Audi A3, the actual A3 e-tron will be based off the next generation Audi A3 at the earliest, which will probably be a model year 2012.  Unlike their current hybrid lines, the e-tron is the name for their all-electric powered cars.

Here are the specs for the Audi A3 e-tron electric car

Front wheel drive only so far, no quattro.  The battery packs are in the middle and trunk area which rules out the rear drivetrain components needed for quattro in this prototype.

Total power is rated at 130 hp and 199 lb-ft torque.

Battery pack: 26.5 kWh.  By comparison, the Volt and Leaf battery packs are 16 and 24 kWh.  (16 is the minimum to get the US government’s tax credit of $7,500).

Estimated range: about 90 miles.  By comparison, the all electric only range of the Volt and Leaf are about (20-50) and (70-100).

0-60 11 seconds

top speed: 90 mph

recharge time: 4 hours with 400 volt rapid charger, 9 hours with a standard 110 volt household outlet

Keep in mind that these are specs on a prototype car only.  However, the specs are very close to the Nissan Leaf’s.  It will be interesting how Audi’s development of their e-tron production cars follows the first modern all electric mass produced car, the Leaf.

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VW Touareg hybrid vs. VW Touareg TDI review

The first real world back to back review of the hybrid vs. TDI has been released in the May 2011 Car and Driver.  Personally, I was surprised by the results.

2012 VW Touareg hybrid vs. VW Touareg TDI review

I don’t own either one of these vehicles but I have driven the Touareg TDI.  Long story short, Car and Driver said that the hybrid is the better choice.  My opinion is that if you’re going to buy a fuel efficient car whose only difference is the engine, get the one that has the most fuel economy.  That’s kind of the whole point.  Above around 30-35 mph, the TDI will have greater fuel efficiency.  Below that, the hybrid will have greater fuel efficiency.  Since most cars are driven mostly at higher speeds except in the city, most people will get greater fuel economy with the TDI engine.  Therefore, my opinion is to choose that engine.

Yes this is a hybrid website but the facts are the facts.  So why did Car and Driver choose the hybrid over the TDI?  The facts are the facts.  The hybrid has better performance with similar fuel economy.  Horsepower is a lot more and torque is as great as the TDI with only a small loss of fuel effiency.  The engines will feel different because the TDI makes its power down low whereas the hybrid’s difference in greater horsepower isn’t felt until medium revs.  If you can live with better fuel economy and much better fuel economy vs. the regular gas engine choices, the hybrid is a good choice.   It does cost a few thousand dollars more than the TDI in similar trim levels but these are $55,000 range cars and a few thousand that that price level is minor.

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