Friday, May 30, 2008

A new Ape in town: Piaggio to concentrate on hybrid vehicle

According to the Reuters news service, Italian scooter maker Piaggio & C SpA cut its sales forecast “in a revision of its business plan” today, due to the slower economy and subsequent weaker sales.
Piaggio ApeThe report of weaker sales is in high contrast to the many reports in the press now of record scooter sales. Their numbers may be due to Piaggio’s flagship scooter line, Vespa, high price points in comparison to other brands of scooters.
However, in green news, Piaggio announced plans to continue its work on development of a four-wheel hybrid vehicle.
“Despite the global downturn, Piaggio said it had kept working on the development of new models, such as a four-wheel vehicle with a hybrid engine.
“Based on a three- and four-wheel light commercial vehicle made by Piaggio called the Ape — Italian for ‘bee’ — it would be big enough for three people to drive around town.”

Tuesday, May 27, 2008

An Engineering Update on Powertrain 1.5

It has been several months since we have shared any progress updates on our powertrain development work and in particular how the “powertrain 1.5” program is progressing for the Roadster.
For those of you not thinking about this every day like we are the powertrain 1.5 is an improved motor, inverter and gearbox designed [...]

Sunday, May 25, 2008

Estimating the Daily Range of a Solar Bicycle

Given that most visitors to this blog seem to be interested in building a solar powered bicycle, I thought it might be helpful to share some information about how you can evaluate the range of such a vehicle based on the solar resources available in your area. My interest in building a solar bike is to extend my daily range on a long bike tour (think cross country) so I want to know "how many solar miles per day?" Here's how we figure that out.

We will need to know the efficiency of our motor. I measured mine by using a Watt's Up power meter (the Cycle Analyst will also work) while riding around a flat parking lot without pedaling until my battery's management system (BMS) cut out. I went 17 miles and used 217 Wh of energy so my motor's efficiency in this scenario was 12.8 Wh/mile (8.0 Wh/km).

Under more typical riding conditions where I'm pedaling most of the time and going over hilly terrain, my power consumption is about 8-12 Wh/mile (5-8 Wh/km) depending on how hard I'm pedaling and how steep the hills are. If you weigh more than me your power needs will increase. If your riding involves a lot of stops your power needs will increase. You will need to run these tests for yourself to get reasonably accurate figures but you can use my numbers as a starting point for your planning.

Next, we will need to assess how much sunshine is available where we will be riding. This chart shows year-round insolation data for the United States. I live in Northern California which is in the light green band between the yellow area in the southwest and the darker green along the Canadian border on this chart. Don't worry about what the colors mean. I've included this chart so you can get a rough idea if you can expect more or less sunshine where you live. Phoenix, Arizona gets more sunshine than I do. Chicago, Illinois gets less. Here's a global insolation map.

While this map is useful for a quick visual assessment, it doesn't give us the numbers we will need to figure out our solar miles per day. For that, we will need to look at the Solar Radiation Data Manual for Flat-Plate and Concentrating Collectors. In the United States, the National Renewable Energy Laboratory (NREL) has been collecting solar radiation data at 239 sites spread across all 50 states from 1961 to 1990. The reports include average monthly sunshine for each site and they take into account weather like clouds and fog. The amount of information available in these reports is overwhelming but I'll show you which figures are useful for our solar bike project.

Let's look at the report of Sacramento, California. We will use this site instead of San Francisco because they're both at the same latitude but Sacramento's weather is more like the weather in Oakland where I live. The San Francisco numbers are a little lower because local microclimates create pockets of fog which reduce the amount of available sun. The numbers I've highlighted show the average number of sun hours per day. This is not the same as number of daylight hours. These numbers take the peak sunshine at solar noon and tell us the equivalent number of such hours per day. You get much less power early in the morning and late in the evening but the total output for the day measured in "sun hours" means "as if the sun had been shining at full intensity for this number of hours."

This is very useful because now we can take my solar panel's peak power output (41 watts in full sun) and multiply it by the number of sun hours per day to get watt-hours (Wh) per day. Please keep in mind that we're not using the panel's theoretical rated output but actual power measured between my charge controller and my battery on a hot day. This panel would probably be rated at about 55 watts at STC but we're only interested in actual, real-world output.

So we have 41 watts in peak sun times 7.2 sun hours in May for a 0° tilt panel for a total daily estimated production of 295 Wh. My actual measurements with the Watt's Up meter confirm this number (based on multiple 50 mile trips). This reflects energy collected per day while riding. To account for occasional shading from trees, buildings, and the rider's body casting a shadow on the panel, we'll subtract 20% from this figure. To account for battery efficiency losses (we have to put in 220 Wh to get out 200 Wh), we'll subtract another 10%. This gives us 207 Wh/day while riding.

On a tour, I may spend half the day riding and half the day with the bike parked in the sun. When it's parked, I can tilt the panel and turn the bike so that the panel is perfectly perpendicular to the sun (dual-axis tracking). My power generation will increase by 45 to 115% compared with 0° tilt, depending on the time of year. The NREL data shows 10.2 sun hours for dual-axis tracking in May. This would give me 41W x 10.2 hrs/day = 418 Wh/day. Subtracting 10% for less-than perfect tracking (maybe we only adjust the panel once per hour) and 10% for battery losses gives me 334 Wh/day during parked "charging mode."

So if I ride half the day and park half the day on my tour, I will generate 207/2 + 334/2 = 271 Wh/day. On flat ground, without pedaling, this translates to 21 solar miles per day. If I add the effect of hills and my pedaling efforts into the equation (8-12 Wh/mile), we have 23-34 miles per day. Adding the power from 2 batteries charged overnight, we get 60-90 miles/day. Adding a second panel (@ 60 watts) we're up to 1128 Wh/day or 94 to 141 miles/day.

Keep in mind that these numbers represent average monthly and yearly figures including all foul weather days with little or no sun. If you're a hard core commuter who rides rain or shine, your numbers should closely resemble these averages. However, if you're a fair-weather rider who selectively avoids days with little sun your averages should look better than these numbers.

Here's how all this looks in a spreadsheet. You can also access the interactive version of this spreadsheet and plug in your own numbers. Some figures may vary from the article above because I update the spreadsheet as I gain additional road test data and better understanding of solar-assist cycling.


Thursday, May 15, 2008

Program Update

The following is a letter that was sent to Tesla Roadster customers today to review key developments in the Roadster program.

Since we last provided a program update we have achieved an extraordinary milestone – on March 17th, the Tesla Roadster entered regular production. In this program update we will focus on a wide variety of [...]

Wednesday, May 14, 2008

Tesla Store Los Angeles

Last week we opened our first ever Tesla Store in Los Angeles on Santa Monica Blvd.
The Tesla Roadster is a revolutionary car and our Tesla Stores will be no less revolutionary as an automotive retail experience.

Store Front
What’s so different? Well, pretty much everything, but here’s the main idea. We want to create welcoming [...]

Tuesday, May 13, 2008

7GEN: Saudi production laid bare

The OPEC Annual Statistical Bulletin provides much grist for exploring the question: "So is Saudi production about to nosedive"? If Saudi production were to nosedive it would indicate the world oil peak having been reached.
Maybe Saudi production nosedived in late 2005. Maybe the Saudi's are voluntarily holding back production so they can manipulate the market.

Summary

Article Reference: 

Saudi production laid bare

OPEC Annual Statistical Bulletin

Saudi Arabian oil declines 8% in 2006

Saudi Arabia and that $1000 bet

A nosedive toward the desert

1986 BP statistical review

Baker Hughes international rig count

the Khurais development

read more

7GEN: We Must Imagine a Life Without Oil

"It used to be that only environmentalists and paranoids warned about running out of oil." But times are changing and there is more and more awareness of the peak oil phenomenon. The ever-rising price of oil and other events are making it abundantly clear that the oil industry is in crisis. "With global demand inexorably rising, a limited supply will bring higher, more volatile prices and eventually shortages that could provoke -- to quote the title of the must-see peak oil documentary -- the end of suburbia."

Article Reference: 

We Must Imagine a Life Without Oil

read more

Monday, May 12, 2008

7GEN: The Oil Nonbubble

In the 1970's there was a fake oil crisis which caught everybody's attention. At least for awhile, until the easily distracted Americans forgot and Reagan was elected, and we went back to driving SUV's as if there were no limit to the oil.

Article Reference: 

The Oil Nonbubble

The peak oil culture wars

read more

Nissan electric Cube at the NY auto show

The 2008 New York auto show had several electric vehicles on it.

Article Reference: 
extvideo: 

Officially official: Th!nk City electric car on sale in the UK this fall

The Think corporation has nearly died so many times it's awesome that they're still alive. It's even better that they're getting close to (again) selling vehicles. This one is the updated version of the original car they sold.

Article Reference: 
extvideo: 

Monday, May 5, 2008

European Vacation (Not)

As I fly back from Brussels and think about the last 9 days in Europe I am very encouraged by what we learned. One of the advantages of a startup operation is the ability to change direction and make decisions very quickly to adjust to the opportunities and risks that present themselves. The flip side [...]

Saturday, May 3, 2008

Jamie Hyneman's "brain child"

Img_1149
Jamie's "Baby" the video on the Barefoot ATV for the Science Channel episode on EVs is now linked on their website check it out here and there's a link on the Mythbusters home page too, also there's some great discussions going on on the mythbuster fan site about the ATV, which is great!

The initial proof of concept Barefoot ATV, the Model One built on a Polaris Sportsman(r) chassis went head to head with a Polaris Sportsman 800. The video is short and it edits down the time trials. On the day of filming BOTH Adam and Jamie rode BOTH vehicles in the time trials. In BOTH cases, Jamie and Adam's time on the Model One was faster in the crazy twisty turny course that was set up, and no advantages were given to the Model One, none at all.

The premise for those of you new to Barefoot is that we're building a comparable electric ATV to a heavy duty gas powered ATV, all in the name of bringing the newest and far better technology to the market. Please feel free to pose questions and discuss the product, we're happy to oblige.

--Melissa Brandao

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