Close to the Limits

We finally had a rainy spell this winter during our drought here in California.  One morning the car actually slipped pretty severely!  The road situation was actually very extreme.  I was driving on a very unusual pavement where half the roadway was a large grate — probably five feet in length.  So two of my wheels were on wet slick pavement and the other two were traversing this highly unusual grate.  For a brief instant the car definitely swerved and scared me a bit but the quickly corrected itself as nothing had happened.  I rarely actually take this particular section of road, but I vaguely remember it being dicey in the past.  I suspect this unusual grate was installed to correct severe flooding problems.

Limited Regen

Limited Regen

Late last year we had a serious cold snap and the garage one morning was around 40 degrees Fahrenheit (about 5 degrees Celsius).  To my surprise, I actually had a dashed yellow line — limiting regen.  While parked the car uses as little energy as possible to keep the battery warm in order to avoid the energy wasting vampire drain.  In cold weather you can drive your car with a cold battery, but the regeneration of energy into the battery is limited.  After only a couple of miles of driving, the battery warmed up and the yellow line disappeared.

 

Limited Acceleration

Limited Acceleration

As I earlier reported, I did a number of supercharger tests where I drained my battery down to 0 rated range.  While intentionally draining the battery, the upper limit of power was reduced — indicated by the dashed yellow line.  I don’t remember the exact rated range left before the power was limited but it was at a significantly lower level than normal.  The car still had enough pep to very comfortably drive.

I also noticed in the rain serious impact to the rear facing camera.  I think this is a problem with all cars.  I had grown a little too dependent on the camera during driving instead of the traditional mirrors and head turning.

Mediocre Visibility in Rear View Camera in the Rain

Mediocre Visibility in Rear View Camera in the Rain

Advertisements

Vampire 5.8

I recently conducted a 10 day experiment on the vampire drain with version 5.8.   My data shows at least a 53% improvement between the 5.8 and 4.5 software, and likely more since the 5.8 experiment occurred in a significantly colder garage.  On an annual basis, the car will use 474kWh of electricity for vampire drain, enough to drive about 1,250 miles.

For more details on the 4.5 results and the methodology of these experiments, please read the blog post.

2 AM Model S Recharge

2 AM Model S Recharge

In 4.5, the Model S consistently woke up every other day.  In 5.8 it woke up either every second or third day.  With the 4.5 software, the Model S took up to 45 minutes to recharge to 50% capacity, and with 5.8 it never exceeded 30 minutes. Oddly enough, one incident did not occur at the scheduled 10:00pm time slot, but occurred at 2:00am.  I almost missed this data point.  The highest usage of kWh by far is the Model S as it pulls about 2.3 kWh in a 15 minute period.  The largest other household usage is at most 0.5 kWh in a 15 minute interval, so I am comfortable in assuming that this 2am energy usage was the Model S.

During the 4.5 test, the average outside temperature reported by my utility was 66 degrees Fahrenheit (19 degrees Celsius).  During the 5.8 test, California had a very long cold spell and the average temperature was 43 degrees Fahrenheit (6 degrees Celsius).  My Model S is parked inside a three car garage facing north.   The garage has a very large volume. The ceilings are about 12.5 feet tall (almost 4 meters) and the temperature is pretty consistent and only during very long heat or cold spells is the garage uncomfortably hot or cold.  I do not have a temperature record of my garage temperatures but I do not think it is as extreme as the daily averages listed by the utility.

The results for 4.5 showed a Vampire drain of 2.75 kWh per day, or 2,700 miles per year.  The results for 5.8 show that number reduced by at least half to 1.3 kWh per day, or 1,260 miles per year.  Because of the weather differences, I suspect the true resulting vampire drain in the exact same climate conditions will be better than a 53% improvement.  Here is the detailed data from the 5.8 experiment where the car woke up three times.  The night of Dec 1, 2013 the car was charged to a 50% reading.

Vampire 5.8 Drain

Vampire 5.8 Drain

And for completion sake, here is the updated 4.5 chart including the average outside temperature.

vampiredrain4.5

Gas Stations

A rare visit to a gas station

A rare visit to a gas station

Can we predict the future of gas stations?  Will they exist in 100 years?  What will happen with all the extra real estate on street corners?  Will some be converted to electric car charging stations?

I’m retesting the Vampire Drain on my Tesla with firmware 5.8, so I am forced to drive my ICE around town for a couple of weeks.  I didn’t realize how much I do not really care for gas stations as I had not been to one in four months.  And how positively lovely it is to fill up your car at home.

For me gas stations are not particularly convenient.  When I found one on my journey today I actually forgot which side the tank was on my ICE!  We are experiencing quite a cold spell here (50 degrees Fahrenheit in California), and it was really quite cold standing outside pumping the gas.  And the pump was broken and could not be left in the latch on position, so I had to nurse the gas into the car.  Afterwards my hands had that distinct smell of gasoline.

I also forgot how busy gas stations can be with too many cars wrestling for a position at the pumps.  They also have lots of advertisements for various products and unappealing restrooms.

With the Tesla there are still two uses for a gas station:  air and window cleaning supplies.  The closest gas station to me will kindly fill up my tires.  Their air pump is not in a public access area, so an employee actually does the filling.  This particular business is one of the nicest I know.  I also have a standup bicycle pump I could use but it would take a while to fill four car tires.  A bottle of window cleaner, a squeegee and a towel solve the window cleaning issue.

Filling up at home is so much more convenient.  A small but lovely luxury and I think the true wave of the future.

Can You Smell the Fumes?

Can You Smell the Fumes?

 

Seven Years of Solar

I just received in the mail the PG&E yearly true up bill.  After seven years of solar, my usage seems to have stabilized to the right amount to match my panels. In this true-up period through mid October 2013, I had a credit of $16.33.  Perhaps 2014 will be the true comparison with the Tesla Model S in use for a full year.  Also I hope I get the new firmware soon without the Model S vampire drain.

I have a 27 panel system with the rated output of 3.8 Watts and an estimated energy usage of 6,884 kWh / year.  I have had the system in use for seven years with a somewhat varied energy usage.  The first two years, the panels were not supporting an electric car and PG&E got a lot of free electricity.  I got the Tesla Roadster during 2009.  In the 2013 true up period, I sold the Roadster and bought the Model S.

With PG&E, you cannot directly find out how much energy you produce or how much energy you use.  You can only know the “net” energy.  Even this data is complicated and broken down into daily chunks of time as the cost of electricity varies per time of day and time of year.  Also, PG&E changes the rates every few years to make a complete statistical analysis difficult.  Other factors include the weather and how dirty your panels are.  I found a substantial increase in production after having my panels professionally cleaned one time.  The second time I had them cleaned I did not notice a particularly significant drop in production.   I did an exhaustive analysis of how much I generated and used in this report.

In summary, my costs or credit for each of the seven years is listed below:

  • 2007    -88.47
  • 2008   -162.98
  • 2009   -29.55      Roadster mid true-up year
  • 2010    381.75
  • 2011    154.27
  • 2012   -123.22
  • 2013   -16.33      Roadster sold Model S purchased

Vampire Drain

After being away from my Tesla for 28 days, I thought I would check on amount of energy my car was using just to keep the battery at a 50% charge.  The amount of energy used for a whole month just to run the instrument cluster was a whopping 77kWh.  In other terms, the energy was almost a complete charge of the battery or a vampire drain of 2.75kWh per day.

In firmware 4.5, the Model S processors that run the instrument cluster and touchscreen do not turn off.  This design allows for immediate response when the driver returns to the vehicle.  Unfortunately this design also uses a significant amount of electricity.  Tesla plans to introduce a setting in the next firmware to control the background electronics while the car is not in use – a sleep mode – that will reduce this vampire energy consumption.

Some owners have experienced this vampire drain as loss of range as they have left their cars unplugged for a period of time.  In my experience, I left the car plugged in at a 50% charge for 30 days, but I can through my utility clearly look at the kWh my car used while I was gone.

The Model S in the current firmware refreshes the battery every other day.  For the 30 day period, half of the graphs look like the graph below where I have a constant house vampire load of less than .1kWh, and some solar power generation during the middle of the day.

Power Usage Every Other Day When the Model S does not Refill

Power Usage Every Other Day When the Model S does not Refill

The days the Model S requested power at 10:00pm, I consistently had the following style of graph with a spike between 10:00pm and 10:45.  On the graph I can extract the three data points for the time ranges of 10:00-10:14, 10:15-10:29, and 10:30-10:45.

Power Usage on Days When Model S Refills

Power Usage on Days When Model S Refills

I realize there is a tiny vampire drain from my house at the same time, but since it is less than .1kWh, I did not include that data and the vampire drain is very marginally smaller than this data.

The following data is the actual raw numbers:

Actual Data From 30 Days of Model S Plugged in But Not Driven

Actual Data From 30 Days of Model S Plugged in But Not Driven

At 2.75kWh per day, that is 1,004kWh per year for every Model S on the road, or equivalent to approximately 12 full charges of electricity that should propel the Model S comfortably 225 miles, or 2,700 miles of driving.

This data is consistent with other Model S drivers on firmware 4.5.  Tesla representatives have reported that changes to the firmware are coming this year addressing this issue.

As an environmentalist, that data number is very significant on a yearly basis.