Regen Gauge

[walk_n_wind]

I totally dig the idea of a regen gauge - does such a thing exist on the Roadster? I'm not a fan of the buttons on the center console, but if I could play FPSs on a QWERTY, I can learn anything, right?

 

[WarpedOne]

Yes, current roadsters have small digital display that shows current going from and into the battery. 2010 roadsters will have redesigned dash with regen instead of current rpms.

 

[donauker]

This screen also shows regen in kW in the upper area. During regen arrow is toward the left.

 

[graham]

There is also a small LCD display underneath the tachometer that shows current amps used/regen. It is not as nice as the screen on the VCS that donauker's post shows, but it is much more convenient to glance at while driving.

 

[vfx]

Just to continue this drifting thread.

Next year will have this.

 

[TEG]

Next year will have this.

As in next model year? As in 2010 models (having skipped 2009s)? As in real soon now?

 

[TEG]

And why make the speedo go past 14K RPMs all the way up to 160 MPH?
Wishful thinking / unlock the rev limiter for racing?
2nd gear coming someday?

 

[graham]

Supposedly, yes - 2010 (the gauge, not the CF).

 

[vfx]

As in next model year? As in 2010 models (having skipped 2009s)? As in real soon now?

The cars should come out in this June - July.

From us.

 

[MarkW]

I personally favor direct touch instead of a separate relative input device - much faster, more direct interaction.

I prefer voice activation. Answering calls, changing audio, and even navigation (with the right software) can all be done with hands on the wheel and eyes on the road. The Acura RL and the Ford Sync both offer very serviceable voice interfaces. Physical controls with distinct tactile identities and audio feedback should provide a second, backup choice that still allows eyes-on-the-road operation.

A flat touch panel looks great; but without out a voice interface, it doesn't seem to offer the tactile geography necessary for safe operation underway.

 

[WarpedOne]

Graham:

There is also a small LCD display underneath the tachometer that shows current amps used/regen.

What nubers do you see under normal driving? Under acceleration, regen?

 

[graham]

Well, my sample size is still way too small to know what is typical yet. In the few trips back and forth to work since I have gotten it, it seems like:

Under acceleration at highways speeds, up a hill I can use up to about 150A -- regen can bring in 35A if I am going downhill.

Typically at 65-70 on the highway it seems to be about 80-110A, but that can drop to 35-55 if I tuck in behind a truck. The first 2 days it seemed like with Standard mode charging I was getting about 175 highway miles on a charge. Yesterday and today that dropped to 150-160 for some reason - haven't figured out why.

Have not tried putting it in Range mode yet to see what the true range is highway-wise - but I would not be surprised if driving semi-conservatively I could get over 200 highway miles on a charge. Of course those numbers only go up when I get off the freeway.

I do not yet have my MC240 (even though I do have an AVCON converter) so I am somewhat afraid of taking it too far from home. There is supposedly a Tesla HPC in the East Bay, and I need to drive to Livermore this weekend, so I was thinking of trying it in the Roadster. I hate to depend on a charger I have never seen before, though.

 

[TEG]

Typically at 65-70 on the highway it seems to be about 80-110A, but that can drop to 35-55 if I tuck in behind a truck.

That 'typical' value seems too high.

Lets say you were using 100A on the highway going 70 MPH for instance... At 350V that is 35kW. In one hour you would use 35kWh... To get 70 miles. So with 52kWh pack your total range would be 104 miles. That seems too low.

Did you do your highway readings while driving uphill on 17?


Now your drafting example... ~45A@350V=16kW. You could go about 3.5 hours at that rate. At 70 MPH that gives about 240 mile range. Would you really have to draft to get the EPA range value if you are going 70 MPH?

By the way, my RangerEV (not being very aerodynamic) gets about 2x range at highway speeds if I am drafting behind a big truck the whole way.

In summary, I would be surprised if you really need 80-110A to maintain highway speeds... Except maybe when going uphill or into a strong headwind.

 

[graham]

Yes, my Highway numbers are Highway 17 and Highway 85.

As I said, my sample size is really small, and the number updates every second, and bounces around a lot. The speedometer may stay at 65, while the numbers go 125, 35, 75, 40 - so I don't yet have a good feeling for what the real numbers are. This is just from my glancing down occasionally during my 4 times driving the car so far. I have not yet done a particularly scientific study. I may be a little more scientific about it if I take it for a road trip this weekend.

 

[MarkW]

That 'typical' value seems too high. Lets say you were using 100A on the highway going 70 MPH for instance... At 350V that is 35kW. In one hour you would use 35kWh... To get 70 miles.

The chart in JB Straubel's blog post on efficiency predicts 300 Wh/mi at 70 mi/h (21kW) and implies a much lower 60A at 350V.

 

[TEG]

According to JB's Roadster Efficiency and Range blog entry, 70mph should use 300Wh/mile. Also range should be about 180 miles at that speed.

So, you should be able to drive about 2 and a half hours at 70mph, 52kWH/2.5 hours=20.8kW per hour... /350V=~60amps.

So, cruising on a flat highway at 70 MPH I would expect you to see something like 60amps, not 100amps.

 

[dpeilow]

Take the handbrake off :biggrin:

 

[graham]

Take the handbrake off :biggrin:

D'oh! I knew I forgot something!