Tag Archives: Tesla

Tesla, the EV

Student Driver

Trust (but verify)

Self driving cars are a few years away. Letting Autopilot take control is like watching an inexperienced beginner on a learner permit. Fortunately, as a monitor (with skin at stake) you can gently intervene or abruptly take-over if the performance is not to one’s liking.

Current state of the art tech with Hardware 2.5 does quite the job centering the vehicle in the lane and maintaining proper distance from the car ahead with adaptive speed. Today, on an extended drive, I was able to sample test the latest enhancement: Navigate on Autopilot (beta) which further extends Autopilot.

Following GPS guidance Navigate on Autopilot suggests lane changes required for the route. Using cameras and forward radar it also recommends an open lane when overtaking a slower vehicle. You, as second pilot, acknowledge the suggestion and give permission with a tap on either stalk on the steering column (ignore is the default). In actuality you are babysitting the proceedings — and like a hawk.

There isn’t, nor should there be any trust expectation between you and the machine. The manufacturer (and his lawyer) feels the same way. Beyond any disclaimer you need to be attentive. The reason is called the automation hand-over. The autopilot can, after the briefest of warning, signal bailout and return control. If your head is not in the game this transfer could be messy. So, autopilot continually confirms that you are standing by. If you’re not detected actually holding the steering wheel you are politely prodded before it becomes serious. The system shuts off / locks out an abuser ignoring any cautionary nags.

Proper technique: the weight and friction from one hand is sufficient to apply “slight turning pressure” which is the assurance that Autopilot is looking for

The autosteer function continually saws back and forth ever so minutely seemingly testing to see that it has not been abandoned. A sensitive passenger may perceive the motion but in comparison to earlier iterations it is fairly smooth going.

Hardware 1.0 was primitive as autosteer would ping pong on secondary roadways hugging the inside line or wandering inebriated opposite. Still, it was exciting to experience this alpha software. Realizing that the future had arrived inspired anticipation for FSD

Lane keeping on today’s trip was quite good during the Interstate portion. There were some, shades of yore, one spurious blip of regen, a wander noted in the tight radii of an exit ramp. A little faith was required but no boundaries were exceeded. I did wonder what any closely following driver might be thinking.

whoa boy (too wild)

This happened… A mowing tractor pedaling the shoulder as fast as he could go — hazard flashers blinking but protruding somewhat into the right lane. Autopilot decelerated for the detected obstacle as it should do. I switched off auto steering and moved to the left lane to pass which was occupied by a truck just ahead. During the maneuver, just as I started over Autopilot saw daylight between Mower and Truck and (adaptive cruise control still engaged) accelerated harshly. Splitting lanes like some deathwish motorcyclist would have been a bit too sporty.

push nudge (too timid)

Autopilot slows as necessary for a vehicle ahead which is turning right onto a crossroad. Ordinarily, a driver can safely resume speed accelerating in anticipation of the other vehicle clearing. Autopilot delays this for a count of 3 before getting on with it. It seems like an eternity because know that the driver(s) behind have lost patience.

advanced nav (passed)

One part of the route today is considered tricky even for an experienced operator. I have traversed it many times and decided to let the student driver have a go. The course begins with an off ramp exit, followed by a double merge, another exit, a sweeping loop where traffic sometimes can crawl or even halt, and then yet another merge — all rapid fire. Autopilot has to steer navigate and sequence with the merging vehicles. It’s the full deal. Tight choreography. Autopilot will slow to make a merge opportunity happen but doesn’t offensively overtake for a cut-in. 

As blue traffic autopilot performed a weave merge with cyan traffic. Green dots depict where autopilot asks permission to exit route leg or for the navigational lane changes.

Eventually cars will computer interface with each other and the dance sequence will be safe and carefree. Until then, it’s student learning so; mind how you go. It’s early days yet.

View from the slow lane

The leg from Atlanta to Burlington is too far for a single charge. There are a Level 2 chargers enroute and this looked like the only option. Ultimately I stopped at the Ivy Acres RV Park as they had a “bigger hose”. I would pay $5 per hour but the wait was reduced by 2 hours had I stopped at the Level 2.

To minimize charge waiting, as these chargers are a slowly flowing spigot, I wanted to conserve energy. This is done by driving very slowly. 55 MPH was a safe target speed. Although 45-50 would have been even better that might have been unwise. Other drivers tend to exceed the posted 65-70 limit and wiz by. It was interesting watching them decide lane choices and to jockey for position. With an EV, traveling at a higher rate of speed only extends your charge time if charging at a snail’s pace. I experimented with a hypermiler technique while cruising the right lane. I waited for a slightly faster Semi Truck (one with the aerodynamic fairings on the trailer to pass me by then position close behind and match speed so as to draft (NASCAR style). The big rig breaks the wind. Aerodynamic drag is the biggest energy consumer for any vehicle and this trick was good for about a 15Wh/mile advantage and at the same time allowing for a +5 mph gain in forward progress. Naturally you don’t want to be unsafe and 200 feet in trail is considered minimum I believe.

Flip the Switch already

Could have been one of the first to use… The new Supercharger in Baton Rouge is finished but still not operational. May be online next week. In the mean time I’m probably one of the last of the pioneers through these parts to make a daytime stop for a necessary top off at the Frog Town RV Park which will see me through to my endpoint as night falls. $10 cash seemed reasonable for the service although this is the first “fuel” money I’ve had to layout. The early EV adopters are slightly spoiled because generally the plugins are free — for now anyways.

To Texas in a Tesla

Glad to get a healthy charge at the Lake Charles Supercharger as I exit Louisiana. Interstate 10 West will take me across Houston to the next SC in Columbus but I will need a boost to make it. The Tesla Houston Gallery has a High Power Wall Connection (HPWC) which is not in the same league as an SC but is a much faster than the RV 50 amp.

An HPWC at a commercial business building, such as Tesla’s garage is 205v and 80 amps. A similar power supply at a residential garage is even better with 240v.

Multiply Volts (v) by Amps (a) and you get Watts. Follows are some interesting results for comparison:

205v X 30a = 6kW or18 mph (Level 2)
240v X 40a = 10kW or 28 mph (RV)
205v X 80a = 16kW or 49 mph (HPWC)
240v X 80a = 20kW or 58 mph (HPWC)

MPH in the context of number of miles range added in an hour.

This listing excludes DC Fast Charging or the most common source of power the 115v common household outlet; subjects for a later post.

Pushing the Envelope

The wait for the Level 2 charge to finish wasn’t that entertaining so in an effort to minimize the sit time I calculated an absolute bare minimum charge.

Caution: Before attempting this stunt, realize that any detour or missed turn will put you at risk.

The challenge was to traverse the mapped out 80 miles and arrive with at least some energy left in reserve. So, I stopped the charge at 93. I figured the 3 bonus miles for my own inefficiencies or for squandering. The 10 miles on top of the 80 was for cushion. Dipping into this minimal reserve would be a Fail.

To achieve a 1:1 exchange of battery range miles for map miles required reduced speed (55), Cruise Control On, HVAC off (Brrrr) — basically wearing knit cap, gloves, and coat jacket while watching the traffic whizz past in the fast lane.

A good monitoring method is to compare predicted range remaining with distance to go. Subtract the map distance from the reported range every few miles or so. This mental arithmetic will keep you alert to a growing or shrinking reserve. If you discover your reserve to be dwindling then further adjust speed.

Interstate 10 through Louisiana is flat and this was cooberated by the realtime energy graph display which was flatlined. This is rare to see for me seeing that the Eastern states have hills always. I felt emboldened with my 3 bonus miles, one of which disappeared early on for some reason, to try an experiment. This was spurred on by the cold tingly feeling in my toes 🙂 Wanting to see the energy consumption diff I switched on the heat. The increase was marked at 50 WH/mi. I had to switch it off, too big a hit, but was able to run the seat warmer on lo in lieu of.

I was able to arrive with the 10 miles intact. This exercise was good experience but ordinarily 30 as a hold back is a good practice.

Close but not quite

I left Biloxi with a Range Charge (260 rated miles) with the Supercharger in Lake Charles (265 miles) as target. It’s frustrating that this stop is just out of reach. A mid route stop in Lafayette will permit the journey on this thin leg. I focused on Moss Motors, a BMW dealership that is friendly to EVs furnishing a Level 2 charger for public use. BMW has an EV offering of their own; the i3, an example of which is featured on the showroom floor here.

There was some uncertainty over this last chance charge option. Would their system be operational? Would it be blocked? Would they co-operate knowing that I’m driving a competitive brand?

Charging now with a flow rate of 6kW. Computing the wait at 2 1/2 hours all for the mere 50 mile extension needed. Comfy waiting in the BMW showroom though.


Zone of Darkness

They haven’t connected the dots between Louisiana and Alabama quite yet. In fact, there are no public charge station along this gulf route at all! However, RV Parks ( the kind that cater to 5th wheel trailers and self propelled Coaches ) have energy. The facility that I chose is clean, secure, was highly rated AND they furnished a 50 amp hookup. It is a standard MEMA 15-40 setup.

The rate of charge is about 28 miles for every hour so the car will be plugged in all night. I could have found my way to a hotel down the street but since I’m paying $38 for the assigned space, I will maximize this value and try ‘Car Camping’.


as Guest

The road trip pauses to enjoy the hospitality of good friends at their lovely home in the Atlanta burbs. I borrow the wall outlet being used by the workshop wood lathe in the garage. This requires a special adapter for my EVSE (Electric Vehicle Supply Equipment) which adds a dongle to interface with this particular socket. Following a DYI allowed fabrication in advance of the visit.

This socket is 220v but 15 amp rated. I’m able to pull nearly 4kW from it. This not the most efficient setup; the onboard chargers like 10kW and can take up to 20kW. A 40 amp circuit would provide the 10kW which would allow for a faster overnight charge but I’m happy for the convenience on this location as the typical household outlet is only 115v. Thank you gracious host & hostess for the juice!


Public Charger Etiquette

A smartphone app acknowledges with an IM when charging is complete. Even though it was late at night and unlikely that there would be additional patrons, I popped downstairs to the hotel garage to assess. I know that when I rolled in yesterday there was trepidation over availability. Not wanting to be that guy who thinks that the charge stall is his personal park spot, I was prepared to move and free the space. Luckily the opposite station was still open and I could remain. The EV was able to complete by 06:30 a cell balancing self maintenance.

Rappora developer Hint: An app that would alert the current (no pun intended) user when there is someone else in queue would be ideal.

End Point

Transiting a dark zone. The last stop was a fast DC charger in North Carolina but the only energy option from there until Atlanta are Level 2 chargers. These are scattered about many communities and work well for adding a few miles to an EV for travel that is local. A J1772 Level 2 charger outputs at 6 kW per hour. At that rate it will take 10+ hours to achieve a full state. This compares to only 75 minutes at the fast charger back in NC.

The South Carolina hotel I’ve chosen features 2 charge stations in their parking garage. I will explore their historic district on foot, have supper, and rest up for tomorrow’s journey continuation. The vehicle is plugged in and will be ready again by early morning.