Results tagged “roadster” from Tom Saxton's Blog

Showing EV State of Charge

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Nissan has done a poor job of communicating state of charge to LEAF owners.

LEAF-SOC.jpgThe first problem with this display is that you can't tell where you are with a simple glance. Quick: how many bars are there? Imagine if only some are lit up, how long does it take to count them? Once you have counted the bars, you have to divide by 12, or multiply by 8.3%. Like I want to do that while I'm driving! There's a nice number there, 93 miles, but the problem is that number varies wildly based on how you've been driving. Your state of charge might be 40% but the range estimate could be 12 miles if you just reached the top of 4,000-foot pass, or it might be 80 miles if you have been descending from that same pass. Likewise for just getting off of a stretch of 75 mph freeway versus getting onto the freeway after a stretch of 45 mph urban thoroughfare.

Drivers need to know what's in the battery unfiltered by a rating on their recent driving.

This isn't just my opinion, or the opinion of a few old school EV fanatics. I keep hearing from new LEAF owners who after a few weeks of driving realize that the estimated remaining miles on the LEAF dash is not useful. It's not that Nissan did it badly, or that it can be fixed by improving their software, it's not what EV drivers need.

Ford is coming out with the Ford Focus Electric this year and is apparently asking for opinions on what drivers want to see on the dashboard.

First off, Ford should be asking what gas car drivers want to see and putting that in their ads, but they should be asking what experienced EV drivers want to see and put that on the dash. Ford should start with dropping a line to the folks at Plug In America.

When I'm driving, I don't want to see animations or flashy graphics in my main field of view. I'm not watching a movie, I don't need special effects, and I definitely don't need running commentary on my driving. The LAST thing I want to see on the dash is any mention of gasoline. Did the Model T need a gauge showing how many bales of hay had been saved?

Please don't let some gas-driving marketing intern design the dash for an electric vehicle based on talking to other people who haven't owned an electric vehicle.

My wife and I have been driving electric for three years and have logged over 38,000 electric miles. We've done lots of local driving and enough road trips beyond our single charge range that we know what we need.

What I do want to see, in order of importance, is:

  1. Speed, preferably numerical, very easy to read at a glance, the biggest number on the screen.
  2. After speed, the single most important information an EV driver needs is the state of charge, SOC. This should be conveyed as remaining charge energy, in numerical resolution comparable to a mile's worth of driving, and not mangled by some unknown function of my recent driving and road conditions.
  3. Instantaneous energy use. This should be graphical and clearly show whether I'm using or generating energy and how much, even when it's a small amount. Having a number would be nice, but not necessary.
  4. Trip meter, preferably selectable from several. Having a trip meter that automatically resets after each full charge would be cool, but we still want user-controlled trip meters.
  5. Estimated miles remaining based on recent driving is rarely useful, but it would probably be weird to not have it available. Most people think that will be useful until they get used to driving electric. Not having it would be a distracting omission for new owners. It can be on the dash, even on by default, but there should be a way to get rid of it, perhaps making it an alternate to an absolute remaining energy number.

The purpose of showing the state of charge isn't really about figuring out how far you can drive with the current charge. The answer to that question depends on too many factors to ever be a meaningful single number on the dash. Instead, the EV driver needs to answer two simple questions:

1) Do I have enough energy to make it to my destination?
2) If the answer to #1 is "maybe", how do I need to moderate my driving to make it?

Most of the time the answer to #1 is an unconditional "yes". An answer of "no" means it's time to find charging, a condition that should be rare if the car is being used for local driving as intended. If the answer to #1 is "maybe", then I need the best information possible to answer #2.

Note that an estimated range is always wrong when it matters because it assumes my driving style and road conditions are going to remain constant. It's basically telling me how I have been driving. I don't care about that. I need the information that will make it clear how I need to be driving for the rest of my trip.

For this reason, the choice of energy unit for the SOC display is critical. I want something more convenient than kWh, something that will not require doing math to interpret the number. If a vehicle has a certain stated nominal range, which corresponds to X Wh per mile (battery-to-wheel), then the ideal energy unit is X Wh. Tesla calls this an "ideal range mile." Call it whatever you like, but it's a very convenient unit of energy as it tells me how much is in the battery and gives me a range goal I can generally meet or even exceed if I need to.

If a car has a nominal range of 100 miles, then SOC percent corresponds to one mile of nominal driving. That's cool, but it doesn't generalize very well. When next year's model has a range of 140 miles, I don't want to have to multiply SOC percent by 1.4 to get nominal miles.

Showing SOC as kWh is even worse. Not only do I have to multiply by some goofy factor, it's a different factor for every car depending on weight and aerodynamics. Showing kWh used as part of a trip meter is awesome, and showing SOC in kWh has a certain appealing geek factor, but I don't want that to be my best-resolution SOC unit.

We'll all be better off if the car companies start showing SOC as nominal miles now.

SOC145.jpg
On the Roadster, an "ideal range mile" is the amount of energy needed to drive one mile on the combined EPA driving cycle and corresponds to driving level highway at about 57 mph in moderate weather. Knowing this number and my miles to destination tells me how I need to drive to make it. This number slowly ticks down as I drive (occasionally ticking up on a long downhill drive), it doesn't fluctuate wildly as I go up and down shallow slopes and small hills. Nominal miles yields a much more reliable idea of remaining charge than an estimated-miles number can.

Having this number enables useful discussions about range and energy use among owners. If someone is planning a trip over the pass from Bellevue to Ellensburg, I can say that I've done that several times: traveling the ~100 miles over the 3,000-foot pass at 60 mph in moderate weather used 113 ideal miles and closer to the 70 mph speed limit used 119. It also makes planning for elevation possible. Every 1,000 feet of climbing uses up about 7 miles of nominal range, and going downhill gives about half of that back. Knowing that simple approximation makes it possible for a driver to plan a trip over a mountain pass just by knowing the required distance and elevation change. If other automakers use the appropriate nominal mile energy unit, these conversations will work across different makes and models, allowing drivers to share approximate energy expectations without a lot of goofy conversion math.

That probably sounds complicated. Just remember, electric vehicles are intended for local driving within their single-charge range. Most of the time the answer to the "do I have enough charge" is "yes, of course you do." It's only for the rare long trip that figuring things out is needed. Having good state of charge information available all the time will allow new drivers to develop experience and insight from their easy local driving that will make it possible for them to figure out which longer trips are practical. It's critical to widespread electric vehicle adoption that automakers get it right.

2008 Tesla Roadster Converted to J1772 Charging

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Cathy and I, with help from Dave Denhart and many others in the Tesla and broader EV communities, have converted our 2008 Roadster and Tesla High Power Wall Connector to use the new industry standard J1772 inlet and plug. This will allow us to charge without an adapter at the tens of thousands of Level 2 charging stations that will be installed in the US by the end of 2011.

j1772-charging-coulomb.jpgWhat we have is functional and completely reversible, but not ideal; we view this as a version 0.9 conversion. As there are very few J1772 charging stations currently installed, and the numbers probably won't take off until late spring or early summer, we have time to develop a better solution before it actually becomes compelling for Tesla owners to convert in significant numbers. I'm sure Tesla Motors could do a much better job of creating an integrated solution and I would prefer that to having the owner community develop a conversion solution.

We've hear rumors that Tesla is developing an adapter, but are still waiting for official word on what, if any, J1772 solution they will provide. While an adapter would give us a way to charge, we have heard from many owners who would prefer to convert their vehicles and charging equipment to the industry standard rather than leave an expensive adapter vulnerable to theft while charging.

Our effort started last summer when Cathy and I began working with Dave to figure out what it would take to build an adapter that would let a Tesla Roadster charge from the Level 2 J1772 charging stations. We discovered that SAE adopted Tesla's extension to the older J1772 communications standard, so a simple pass-through connector that converts Tesla's charge inlet to the J1772 inlet will allow charging to occur, although there is an issue, which is explained below.

Once we understood the protocol, Cathy and I built and tested a pass-through adapter. When I let the Tesla owner community know about our adapter in mid-September, I wasn't surprised to hear that lots of owners were thinking about those thousands of chargers, but I was surprised how nearly all who expressed an opinion agreed with us that the right way to do this was just to convert the Roadster to use the J1772 inlet. From what I'm hearing from new and prospective owners, it seems to me that many potential Roadster customers are put off by the Tesla plug and this is probably already becoming a barrier to sales.

In the absence of any word from Tesla Motors about a J1772 upgrade path, we've been slowly working toward doing a conversion ourselves. A few weeks ago, we finally obtained an ITT Canon 75A UL-approved inlet and plug pair from Clipper Creek. The plug cord is intended as a replacement cable for Clipper Creek's model CS-100, and carries the same power and signal wires as the TS-70 aka Tesla's High Power Wall Connector (HPWC, formerly the HPC). Clipper Creek also sells a holster for the J1772 plug that can be used to replace the holster for the Tesla plug.

With the necessary hardware in hand, we starting tackling the engineering challenges in getting the inlet mounted inside the Roadster's charge port: there's limited space to work with and the Roadster wasn't designed with the shape of the J1772 plug in mind, so getting the plug and cord to clear the body is tricky. It took a bunch of measuring, brainstorming, numerous experiments, a couple of laser-cut bracket prototypes, some Dremel work on the inlet cup, and then an adapter designed in CAD and printed on a 3D printer to get something functional.

This is what the back of the upgraded inlet port looks like. The blue piece is the mounting plate Cathy designed in CAD and we fabricated on a RepRap 3D printer at Metrix Create:Space.

inlet-adapter-plate.jpgHere's the work in progress just before installing the J1772 inlet and putting it all back together:

ready-to-assemble.jpgHere's the inlet mounted in the Roadster's charge port:

inlet-in-chargeport.jpgThe ITT Canon cord plugged into the Roadster's charge port:

plugged-in.jpg
Charging from our HPWC, now converted to J1772.

j1772-charging-home.jpgThe top of the inlet tilts back to angle the J1772 cord up. This works pretty well for the ITT Canon cord with enough clearance at the top of the port that it's easy to slide the plug in and engage the lock, easier than plugging in the Tesla connector in fact. The rubber strain relief on the cord barely rests on the body, plus our Roadster has the paint guard protection there, so I'm not worried about that minor contact damaging the paint.

itt-canon-cable.jpgIt's not quite as nice with the plug and cord used by the ChargePoint Coulomb chargers, but I think it's OK for use on the occasional road trip.

coulomb-cord.jpgIn addition to the cable clearance issue, there's another concern with our v0.9 conversion strategy that has to do with the largest difference between the Tesla and J1772 communication protocols.

The Tesla plug uses four contacts: two for power, one for ground and one for the pilot signal. The pilot signal is a low-voltage communications protocol that allows the charging equipment to tell the car the maximum amperage supported and allows the car to ask for the power to be turned on and off. The pilot signal is not connected to the car until the plug is connected and the locking switch is engaged. This switch plays a second role: if the driver tries to remove the plug in the middle of a charge, sliding the switch back interrupts the pilot signal which tells the car to stop charging. This happens very quickly so that the driver cannot get the plug untwisted and removed to break the electrical contacts while current is still flowing. It's important to prevent this because doing so can cause arcing, which would damage the contacts.

Instead of interrupting the pilot signal, J1772 uses a fifth wire for this purpose. Like the Tesla plug, the locking mechanism on the J1772 plug makes the proximity connection, so that when the driver wants to remove the plug and slides the lock it interrupts the proximity connection, thus telling a J1772 car to stop charging immediately (within a tenth of a second). Unfortunately, the locking switch on the J1772 plug doesn't interrupt the pilot signal.

With our v0.9 conversion (or a simple pass-through adapter), the driver can unlock the J1772 plug without the car knowing, and then pull the plug while power is flowing. Cathy and I need to make sure we don't do that. To solve this issue, we need to design a circuit that watches the proximity pin and interrupts the pilot signal when the J1772 plug is unlocked. I don't expect this to be difficult, but we haven't done it yet.

We have already made some improvements in the design. This is version 3 of Cathy's inlet mounting plate design, which we plan to print for our next revision:

bracket-front-v3.jpgIn addition to the improved mounting plate, our next steps are:

1) Hope that Tesla Motors provides an official conversion solution before it matters to most owners, thus saving us the remaining steps.

2) Design a circuit to monitor the proximity pin and disconnect the pilot signal when the J1772 plug is unlocked.

3) Test with other J1772 plugs and possibly work on a better solution for cable clearance over the body panel.

4) The 2010 and later Roadsters have the inlet cable assembly connecting to the PEM in a different location. There may also be other differences. We haven't looked into it yet and don't know if it will be more or less difficult to convert than the 2008 Roadsters.

5) Before recommending an unofficial conversion to other owners, we'll need to find out how this will impact our warranty. Tesla Motors has been cooperative with our efforts: they sold our group an inlet cable assembly so that we could do the conversion reversibly. We hope they will continue to be supportive rather than forcing us to wait until our warranties expire before being able to effortlessly access standard J1772 public charging stations.

Sammamish to Mt. Rainier

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On Monday, the weather was too nice to not be out driving so I decided to take a spin up to Mt. Rainier to see if the roundtrip could be done on a single charge. Thanks to Todd Laney for planting the seed by suggesting it as a possible Roadster owner drive route to follow our adventure on Sunday.

I used Google maps to plot a route and get mileage/time estimates. Google estimated the drive at about 2:30 and my goal was to make the roundtrip in four hours. On the way back I took Highway 18 instead of Cedar Grove Rd SE, which wasn't that scenic and smelled of landfill.

I left our house at 4:00 pm, with a full standard mode charge at 194 ideal miles. I reset the trip meter so I could easily track mileage and energy used. I left later than I had hoped, and I paid for it by being stuck in traffic pretty much the entire way from Issaquah to Enumclaw. That didn't help with my four-hour goal.

Give or take a few stunning views of Rainier near Black Diamond, the drive didn't get fun until I left Enumclaw (and the traffic) and got onto SR 410, a two-lane road through forest. I was pushing to make up lost time, but mindful of the risk of deer crossing the road, so I kept the speedometer at or a little above the speed limit. I didn't see much traffic and only passed one vehicle, a van going well below the speed limit.

I neglected to record state when I entered the park to begin the ascent up the mountain, but I recall the battery being around 90 ideal miles and the trip odometer would have been around 70. At about 4 miles from Sunrise, the trip and battery state crossed at 79 miles driven and 79 ideal miles left in the battery pack. If I were on level ground, I would have been considering bailing at that point, but I knew I had used extra energy climbing that I would get back on the descent. Also, I was still driving in standard mode, so I could switch into range mode to get another 25 miles of range.

The best part of the drive was the winding ascent up the mountain, wonderful conditions for the Roadster, although the road was pretty uneven in spots. I was having fun but not being crazy about it. Two thirds of the way up the mountain, I came up behind another car and resigned myself to taking the rest of the drive at his pace, which would have been fine. However, as soon as I came up behind him, he immediately pulled over to let me pass. I don't know whether he was scared of the red sports car, or just really nice. I waved in appreciation as I passed.

I arrived at Sunrise at 6:08 pm, just a few minutes later than my goal time. I let the car sit for a few minutes while I tracked down a restroom and snapped a quick photo. Ready for the return drive, the trip meter said I had driven 83.7 miles and used 28.01 kWh. The touchscreen altimeter said 6300 ft, temperature at 60 F, with the SOC at 47% and 69 ideal miles (standard mode).

0256-090921-tws-IMG_3554.jpg

For the descent, I got regen nearly the entire way. I stopped twice on the way down, once at the viewpoint just below Sunrise where I got my cell phone signal back and called to update Cathy on my progress, and at the bottom to record data. At the park exit, 14.0 miles from Sunrise, the battery state was up to 71 ideal miles, a net gain of two ideal miles from the reading at the top.

I was treated to a beautiful sunset with a thin crescent moon just above the horizon as I was finishing up the drive on SR 410 approaching Enumclaw.

I had a TomTom GPS navigation device programmed for the route home, mostly to show me remaining miles and ETA. When I left the summit at 6:20 or so, it was predicting I would get home just before 9:00, which was obviously wrong since I made the trip there in just over two hours. After exiting the park, the ideal miles tracked the remaining miles pretty closely, showing a buffer of about 10 miles the entire way, while the ETA dropped steadily.

I got home at 8:20, missing my four-hour goal by about the length of my stops. The trip meter read 168.8 miles and 41.76 kWh. Our house is about 100 ft elevation, so the trip involved climbing then descending 6,200 feet. The battery pack was showing a temperature reading of four (the highest of the blue ticks), PEM and motor at 3. After sitting for 20 minutes to stabilize, the state of charge read about 5% of the battery left, 9 ideal miles.

Charging back up to full (standard mode) from 240V/40A took 5:20 and put 44 kWh back into the battery pack. The meter on the wall indicated it pulled 50.0 kWh hours, or 296 Wh/mi from wall to wheel, about 12% below my average of 336 Wh/mi.

If Watt-hours per mile doesn't mean anything to you, at 9 cents per kWh for "green power" from Puget Sound Energy, it cost me about $4.50 to drive 168.8 miles, or about 37.5 miles per dollar of green electricity.

My take-away from the drive:

  • The roundtrip can be done on a single standard mode charge, but if you have a passenger or are farther away than Sammamish, I'd recommend a range mode charge.
  • If you do it on a weekday, start early enough to avoid the evening rush hour.
  • Take a credit card: it costs $15 to get into the park via the automated kiosk. Cash might also work.
  • Driving through the woods at sunset on a warm day leaves the front of your car covered with a thick layer of bugs.
Updated July 12, 2011: Fixed link to route map.

Drag Racing a 2008 Tesla Roadster

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I joined four other Seattle-area Tesla owners in driving down to Portland for the NEDRA Wayland Invitational IV electric vehicle drag racing event at Portland International Raceways on July 24th and 25th. My friend Richard wasn't due to receive his 2010 Roadster for another week or two, so he and I shared the driving and the racing in my car.

None of us had any previous drag racing experience, we were just doing it to promote electric vehicles by showing a bunch of people that EVs can be as fun and powerful as gas-burners without sending a bunch of our our dollars overseas or dumping CO2 into the atmosphere.

Over the two days, thanks to Northwest Handling Systems, John Wayland, James Morrison, and several others behind the scenes, who arranged charging both on and off the track, I was able to post the best time in a 2008 Roadster: a 12.982 second 1/4 mile ET at 103.48 mph. The best Roadster time was set by Scotty Pollacheck (the professional driver/rider of the famous Killacycle) in James Morrison's freshly-delivered 2010 Roadster sport: 12.643 second 1/4 mile ET at 102.89 mph.

At the Wayland Invitational, I got to race head-to-head against other 2008 Roadsters using the same driving technique and as well as controlling other parameters. Having Richard racing in my car allowed me to compare how weight changed times with other parameters held constant. Also got to race against the famous White Zombie. We had two nights there, one with charging at the track and one without. My YouTube channel has some videos from that weekend.

Two weeks later, the same group of owners spent another evening at Pacific Raceways in Kent, WA this time with Richard driving his shiny new 2010 Roadster. I was able to do some more experiments there.

Based on what I've seen so far, it breaks down like this:

13.40 seconds: 2008 Roadster, medium weight driver with a cool battery pack, single foot start, traction control on, racing in warm weather at sea level.

0.32 seconds - having a warm battery pack from a recent 240V/40A charge
0.10 seconds - traction control off
0.07 seconds - lose 20 to 30 lbs of driver weight
0.07 seconds - two-footed start (indirect estimate)

I didn't compare single foot launch and two-foot launch with all other parameters controlled. From otherwise similar runs in Portland and Kent, I saw a difference of about 0.07 seconds, but that was different tracks, different charge profiles and different ambient temperatures. The other delta were pretty well controlled.

One owner in Portland increased tire pressure to 40 psi all around trying to shave off a few hundredths to break into the high 12's and didn't get any benefit.

There's also some variation from car to car depending on how well the motor was wound, etc. While there was about 0.07 seconds difference between Richard and me in my car (presumably due to weight), there was a much smaller difference between Scott in his car and me in mine (0.04 seconds) even though I would guess the weight difference to be similar.

I didn't sense the stock tires spinning even with a two-foot launch and TC off, so I don't see how sticky tires would help on a 2008 Roadster. I have confirmation from Tesla to not expect the 2008 Roadster to spin the stock tires with TC off when on dry pavement and driving in a straight line. (That said, I am not recommending turning off TC in any other circumstance.)

I didn't get a chance to try all of the optimizations on the same run. It was only on the second day of the Wayland Invitational that I had a chance to charge up at the track and that was before I learned about the two-foot launch technique in detail, and also before I had the nerve to turn off traction control. So, I don't know what happens when you stack up all of the techniques together.

According to my data, getting a stock 2008 Roadster under 12.8 is going to take a trick I don't know about. Perhaps a driver under 100 lbs, or driving at higher altitude could do it. It might also help to fold back the side mirrors to reduce drag. It will be interesting to see what happens at the NEDRA nationals in Denver in September.

The New Tesla Prices

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Here is the new pricing table updated with the information in the letter sent to Tesla Roadster owners on January 16th. This is an unofficial compilation for comparison purposes, based on my understanding and interpretation of the old and new packages, options and prices. Please post any corrections in the comments.

The email describing the new options and pricing did not detail the cut-off between the old pricing and new pricing, but I believe the new pricing applies to all 2008 model year Roadsters which had not already entered production. I will update as details become available.

Note that there are significant changes from the options communicated to owners nearing production earlier in the week.

The following options were previously available and are now available at adjusted prices and in different bundles:

  Original ($) Current ($)
SolarPlus Windshield (included) 400
High Power Connector (included) 3,000
Forged Alloy Tesla Wheels (included) 2,300
Painted Hardtop 3,200 3,200
Metallic Paint 500 1,000
Premium Paint 1,000 2,000
Paint Armor approx 1,400 1,495
Premium Interior 1,800 1,800
Floor Mats 125 150
Mobile Connector (120V/15A & 240V/40A) 350 N/A
Mobile Connector (120V/15A) N/A (included)
Mobile Connector (120V/15A) Additional N/A 600
Mobile Connector (240V/30A) N/A 1,500
Upgraded Stereo Head Unit
with Navigation System
1,200 N/A
Bluetooth 100 N/A
Sat Radio 400 N/A
Premium Speakers 800 N/A
Homelink door opener (included) N/A
Electronics Group
(includes above 5 items)
N/A 3,000
Destination Charge 950 1,950


The apparent change in the 240V mobile charger from 40A to 30A may be to satisfy regulatory requirements. I will update this when I find out more from Tesla.

These are new options not previously available:

  Price ($)
Executive Leather Interior 6,000
Premium Carbon Fiber and Leather Interior 9,000
Clear Carbon Fiber Hardtop 5,000
Clear Carbon Fiber Accent Group 9,000
Performance Tires 850
Custom Tuned Adjustable Suspension 4,000
Battery Replacement 12,000
Extended Warranty
(2yr/24,000 miles, excludes battery)
5,000


At this time, we don't know what the performance tires are or how they compare to the current and previous standard tires. I will update when we learn more.

Price Increase

The price increase for owners who had previously locked in their options depends on which options were chosen and which previously standard options the owner is willing to give up. Here are some examples:

Increase Scenario
$ 1,000 New base model, losing alloy wheels and SolarPlus windshield, and replacing HPC with 120V/15A mobile connector.
$ 6,700 The previous base model configuration with no options added, which includes the HPC, the SolarPlus windshield and the silver forged alloy Tesla wheels; also gets 120V/15A mobile connector.
$ 9,350 Fully loaded model from previously available options, mobile connector reduced from 240V/40A to 240V/30A.


Revision History

  • Jan 17 2009 13:44 PST: revised table of examples to include original base model.
  • Jan 17 2009 23:32 PST: confirmed that Homelink transmitter was standard equipment.

Tesla Increases Prices on Locked-In Orders

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Update: Tesla Motors announced the new options and pricing to all owners on Friday, January 16th. I've posted an updated analysis.

Tesla Motors is in the process of rolling out price increases to their customers who have pre-ordered a 2008 model year Roadster which has not yet entered production. Customers whose cars are about to enter production, after a two-year wait and a fourteen-month delay, are right now getting phone calls in which they are told they have to accept this price increase and re-select options before their car can go into production. This price increase applies to all 2008 Roadster orders starting with VIN 210.

These 2008 model year customers were given a base price of $92,000 and required to make a substantial deposit at a small start-up company with no experience in producing cars. Those early deposits of $30,000 to $50,000 were used along with investment capital to fund the development and early production of the Roadster. Around the time that Tesla delivered their first production car in February of 2008, they opened orders for 2009 model year cars at an increased base price of $109,000 to reflect both increases in their cost projections and also the then-proven ability of the company to produce cars.

Customers whose cars are going into production this month were required to lock in their option selections in September. All customers with orders for 2008 model year orders, some 600 cars, were required to lock in their selections by November of last year. Tesla Motors is unlocking those selections, raising the prices, and requiring owners to reselect their options with the higher prices.

This is coming as a big surprise to owners being informed of this given that they locked in their options and price months ago. A casual reading of our contract sure makes it sound like once we locked in our choices we were committed to buying the Roadster with those options, and Tesla Motors was committed to delivering that package for the price we agreed to.

Here is the table of original and current options and prices as provided by Tesla Motors on January 14th, 2009.

  Original Price Current Price
Base Vehicle $92,000 $92,000
SolarPlus Windshield (included) $400
High Power Connector (included) $3,000
Mobile Connector $350 (included)*
Hardtop $3,200 $3,200
Metallic Paint $500 $1,000
Premium Paint $1,000 $2,000
Premium Interior $1,800 $1,800
Floor Mats $125 $150
Navigation System $1,200 N/A (see stereo bundle)
Bluetooth $100 N/A (see stereo bundle)
Sat Radio $400 N/A (see stereo bundle)
Premium Speakers $800 N/A (see stereo bundle)
Stereo Bundle N/A $3,000
Destination Charge $950 $1,950
New Options
Performance Tires N/A $1,150


The most obvious price increases are from the unbundling of the high power connector (HPC) and a $1,000 increase in the destination charge. The HPC connects the Roadster to home power for rapid charging. Previously, the HPC was included in the price of the Roadster for early orders. (Tesla had previously unbundled the HPC for 2009 model year orders.)

A second big change is the removal of à la carte audio upgrades. Previously, owners could choose to separately upgrade the speaker system and head unit (including a navigation system). With the upgraded head unit, owners could choose to add support for Sirius satellite radio and/or Bluetooth mobile phone integration. Now all of these items are available only as a single bundle for $3,000, which is $500 more than the total system cost originally. The option of spending just $800 for the built-in premium speaker system is no longer available, a disappointment to owners who wanted the factory speaker look with an aftermarket head unit.

There's also a subtle change in the mobile connector. Previously, owners were able to order a mobile connector for charging away from home. The promised mobile connector was to be compatible with both 120-volt and 240-volt connections using a variety of outlet adapters. Tesla later discovered regulatory hurdles to selling a 240-volt connector, so now owners have only a 120V/15A connector that takes about 37 hours to charge a fully depleted battery pack. Said another way, the mobile connector charges at a rate of about 6 miles of added range per hour of charging. Tesla is now including that 120V low-power mobile connector at no charge, with no timeframe or cost estimate for the 240V/40A mobile connector.

According to Doreen Allen, Tesla Motor's reasoning for the price increases is that they are working hard to get to being profitable on each Roadster delivered, and that the federal tax credit of $7,500 which became effective on January 1, 2009, means that the net effective price of the Roadster decreased at the beginning of this year. Additionally, the à la carte audio options were creating too much complexity in production and had to be consolidated to be sustainable.

This owner finds it particularly galling that he and his wife got the message from Tesla that our car is being held from starting production until we agree to these sudden, retroactive price increases on the same day that Tesla Motors published a blog Tax Incentives: Why the Roadster costs less than its sticker price.

On a personal note, we complained a lot, but in the end picked a set of options and agreed to pay the price increase because we want Tesla to be successful and we want our car as soon as possible. It didn't seem worth it to spend a week complaining and arguing about it, not when our car was ready to go into production.