Print

Please login or register.
1 Hour 1 Day 1 Week 1 Month Forever
Login with username, password and session length

[Richard230]

Terry  (offthegrid) Hershner got a ticket in Texas last year for doing over 90.   

[protomech]

It seems Zero is not the only one with a cold range estimation problem.
http://www.nytimes.com/2013/02/10/automobiles/stalled-on-the-ev-highway.html?pagewanted=all

Tesla’s chief technology officer, J B Straubel, acknowledged that the two East Coast charging stations were at the mileage limit of the Model S’s real-world range. Making matters worse, cold weather inflicts about a 10 percent range penalty, he said, and running the heater draws yet more energy. He added that some range-related software problems still needed to be sorted out.

Tesla does have a pretty decent range estimation page here:
http://www.teslamotors.com/goelectric#range

Range loss from dropping from 50F to 32F (HEAT ON) at the following speeds:
55 mph, 7.4%; 60 mph, 6.8%; 65 mph, 6.0%.

With heat off, range loss from dropping temperatures is 2-3% typically.

Range loss at 32F (NO HEAT) for increasing speed:
50 -> 55 mph, 8.0%; 55 -> 60 mph, 8.0%; 60 -> 65 mph, 8.0%.

Note these are cumulative, so 50 -> 65 mph is 22.1% range loss.

I'll edit this post in a bit with a better description of the trip and what Tesla's range estimation software seems to do.

[benswing]

Apparently the blogger who did the test drive misled his readers.

http://www.cnbc.com/id/100439335

I'm more inclined to believe Musk on this one since they can measure the details of the car.

[protomech]

I doubt anything in the story was fabricated - unlike say the Top Gear Tesla Roadster review. But I also don't doubt Tesla has their own side of the story.

So what went wrong?

1. Presumably, the driver did not charge overnight. Even a 1 kW 110V charge could have helped keep the batteries warm. Not charging at low SOC (33%) followed by a drop down to 10 degrees F resulted in a similar spook to my trip that prompted this thread.

2. The driver did not wait for a full charge at the Milford, CT charging station. His planned Stonington -> Groton -> Milford route is around 135 miles. With 185 miles indicated, I can see how he thought there was sufficient buffer. Nevertheless, if he knew ahead of time that he was not planning to charge overnight then an extra 15 minutes here could have saved him a ton of grief.

3. The Newark and Milford, CT Supercharger stations are a stretch for the 85 kWh Model S in cold weather. The 60 kWh Model S would have little chance of making the trip in the best of circumstances - I imagine Tesla eventually plans to build a midpoint station. Tesla's optimistic range indicators did it no favors here.

4. Either the driver was not adequately prepped for this trip with respect to points 1-3 or he neglected them. While the Supercharger is badass, a ~800 mile weekend trip in 10-30 degree weather is just four stops to charge is at the edge of the Model S's capabilities. Electing to not wait for a full charge and to not charge overnight is either operator neglect or education neglect. I guess we'll hear more about this soon.

***

Google Maps approximation of his route. 100% guessing as to the delivery subdivision location, but figure it's about 100 miles from Newark. Letters correspond to the locations on the map.


A Maryland suburb, near Washington DC

0 miles into trip. Car delivered with full charge. 30 degree temps, heat on, drove at "normal highway speeds" toward Supercharge station in Newark, DE.


B Newark, DE Supercharger station (~100 miles from suburb)

~100 miles into trip, ~50% SOC. Charge until full, 49 minutes. 242 miles range indicated.


C Levittown, NY (68 miles from Newark)

168 miles into trip. 157 miles range indicated. Climate control turned to low, cruise control set to 54 mph.


D Manhattan, NY (~134 miles from Newark)

234 miles. "After a short break". 79 miles range indicated. 73 miles to go to Milford, CT.

287 miles. < 10 miles range indicated. 20 miles to Milford, CT.

~300 miles. 0 miles range indicated. Car shuts off heater and informs user to "Recharge Now". Journalist presumably coasts on "fumes" into Milford, CT.


E Milford, CT Supercharger station (~210 miles from Newark)

310 miles. 0 miles range indicated. Charged for "nearly an hour". Car probably at 75% SOC.

310 miles. 185 miles range indicated. Car departs for Groton, CT driving "slowly". Stop at Stonington, CT for dinner.


G Groton, CT (46 miles from Milford, CT)

389 miles, evening. 90 miles of range indicated. Overnight stay, no charging. Plan to return to Milford, CT in the morning.

389 miles, morning. 25 miles of range indicated. Temps now 10 degrees. After battery conditioning cycle, 19 miles range indicated.


H Norwich, CT (~11 miles from Groton)

400 miles. Charged at 6 kW J1772 station "for an hour". Drove towards Milford, CT Supercharger @ 45 mph.

447 miles. Ran out of charge near Branford, CT. Car shut down and coasts down an exit ramp. Tow truck dispatched. Tesla pulled onto flatbed (parking break would not release), towed to Milford, CT.


J Milford, CT Supercharger station (~71 miles from Manhattan)

462 miles. Charged for 80 minutes. 216 miles of range indicated. "Uneventful" trip back to Tesla dealer in Manhattan, NY.


K Manhattan, NY

533 miles. 124 miles of range indicated. Presumably journalist rents a car (ha!) or more likely scores another press vehicle to return home.

[protomech]

A somewhat defensive update from the NYT:
http://wheels.blogs.nytimes.com/2013/02/12/the-charges-are-flying-over-a-test-of-teslas-charging-network/

I still think setting off for a ~130 mile round trip with an overnight cold soak w/o recharge at approximately 65% SOC (185 miles indicated) was a mistake, particularly given his previous experience with consuming range @ approximately 120% the indicated rate. 130 miles = expected to eat ~155 miles indicated range.

[NoiseBoy]

Got a bit confused as to which thread this is in, all the gory details are here:

http://www.teslamotors.com/blog/most-peculiar-test-drive

[protomech]

I'm continuing the Tesla discussion in a new thread, as I'm poking it more and more off-topic. Suffice to say that Tesla's range estimation also has trouble with a deep cold soak.

http://electricmotorcycleforum.com/boards/index.php?topic=2697.0

[protomech]

Zero has posted some guidance for cold weather and hot weather operation and storage of the bikes.

http://www.zeromotorcycles.com/owner-resources/Guidelines-for-Hot-and-Cold%20Weather-Operation-SV-ZMC-012-050.pdf

Cold weather operation of the motorcycle has no permanent impact on its battery pack/cells; however, the ridermay notice a temporary reduction in range due to the effect cold temperature has on the amount of energy the pack/cells can release. The colder the weather, the greater the effect; so that, as compared to operation in 80F/27C ambient, at 30F/-1C ambient, the rider could experience a temporary reduction in range of up to 50% [2011 Model Year] or 30% [2012-2013 Model Year].

In extreme cold weather the motorcycle may also experience a temporary reduction in power and, correspondingly, achieved top speed.

It is not recommend that the motorcycle be ridden while its battery temperature is below 23F/-5C. If it is, its battery needs to be put on the charger at a temperature above 32F/0C as soon as the ride is concluded. It is worth noting that the Battery Management System (BMS) will not allow the battery to be discharged below -22F/-30C, which the absolute lowest discharge temperature prescribed by the cell manufacturer.

Storage of the motorcycle for the winter in a non-heated garage is acceptable, as long as (1) the coldest temperature in the garage does not fall below -31F/-35C, (2) the battery is left on the charger continuously, and (3) the battery is initially topped off at a temperature above 32F/0C. Storage temperatures below -31F/-35C may result in accelerated permanent decay of the battery performance, and hence it is not recommended. Above this temperature, working as a system with the BMS, the charger will ensure the battery survives winter storage with no permanent damage, even if the temperatures dip well below freezing for weeks at a time. Note that, to prevent battery damage, the BMS will prevent the charger from charging the battery at a temperature below 32F/0C.
Again, as long as the battery was initially topped off by the charger above 32F/0C and remains on the charger through the winter at temperatures above -31F/-35C, the system will guard the battery from damage.

It's worth noting that my range has returned to normal after the winter FINALLY ended. Spring riding is so awesome.