Phoenix Range Test Sept 15, 2012 planning!

[TonyWilliams]

Loops:

PADT charging station is 0.3 miles from the freeway.

50.4 miles - BIG LOOP - 101 North, 202 East, South, West, then 101 North

40.4 miles - SMALL LOOP - 101 North, 60 East, 202 South, West, then 101 North

21.8 miles - LEFT LOOP - 101 North, 60 WEST, 10 South, 202 East, 101 North

LEAF's are expected to have ranges at 62mph of:

100% 12 bars - 84 miles (One Big Loop, One Small Loop - come up short by 6.8 miles)
85% 11 bars - 72 miles (One Big Loop, One Left Loop - close)
79% 10 bars - 66 miles (One Small Loop, One Left Loop - come up short by 6.2 miles)
73% 9 bars - 61 miles (Small Loop, Left Loop - close)
66% 8 bars - 56 miles (One Big Loop - pass by 5.6 miles)

 

[EatsShootsandLeafs]

I didn't catch if this was discussed, but what's the reason for covering the speedometer?

I don't think most people are used to looking over at GPS as their speedometer. Could add an element of danger. I'm unfamiliar w/the terrain, but wouldn't there be an issue of GPS speed deviating from actual speed of the car on inclines?

Anybody not familar or safe with GPS shouldn't participate. The GPS is the tool for measuring speed. Hopefully, the driver will accelerate once, to 62mph, turn on the cruise control, and set the speed. If the speed is high or low, use the little "paddle switch" one click up for increasing speed on MPH, and once down to decrease each mph.

We can't use the speedometer on the car, because we don't know if ANYTHING is accurate on the car. Data will come from external sources to the LEAF, and only augmented with the LEAF data after the drive.

The cruise control will hold speed, unless you hit the brake, or it goes into Turtle mode. When Turtle happens, turn off the cruise control and get safely off the highway, in a position to be towed. Turn on the four way flashers.

We won't be going up and down inclines.

I see. So, there are no elevation changes anywhere at all during the route(s)? The routes are totally flat?

I'm concerned about deviation from actual speed the car's traveling (as read from a speedometer) vs. what GPS calculates. (I actually am now curious about this and am contemplating doing an experiment myself w/my Garmin GPS unit vs. my Prius' speedometer. There are some hills and area w/slight inclines near me.)

If I may, i think y'all need to be careful over complicating it. There are already a huge amount of variables covered for (I had thought of ballast for drivers but didn't think anybody would actually go that far with this!) and a lengthy check list. If the cars are varying in speed between 59 and 65 that's not as good as a constant 62 but as far as the test is concerned would be little more than noise, IMO. It's very important that the instructions be simple enough that all drivers can execute them consistently.

I'm really excited to see what happens on the 15th

 

[cwerdna]

If I may, i think y'all need to be careful over complicating it. There are already a huge amount of variables covered for (I had thought of ballast for drivers but didn't think anybody would actually go that far with this!) and a lengthy check list. If the cars are varying in speed between 59 and 65 that's not as good as a constant 62 but as far as the test is concerned would be little more than noise, IMO. It's very important that the instructions be simple enough that all drivers can execute them consistently.

I'm really excited to see what happens on the 15th

The above is sorta why I questioned covering the speedometer.

If one goes by GPS speed instead (where error should be introduced by slopes) and the driver ends up mucking w/the CC to bump the speed up/down to maintain "constant" speed per GPS, that's possibly worse than using the speedometer and leaving it alone (assuming it can maintain speed reasonably well). In the latter case, it should be truly based on the wheels vs. the ground.

 

[garygid]

The very minor grades should not change the GPS indicated speed
significantly.

However, it appears that you are suggesting driving 62 mph true (GPS)
speed, which would be about 64 mph indicated by the LEAF, if one
could see the dashboard, which they will not be able to see.

Perhaps best to NOT cover the part of the "eyebrow" where the red
and yellow Master Warning lights are located (on the left)?

Cheers, Gary

 

[TickTock]

A few questions:
1) What is "Plan B?"
2) Is there a preferred Android GPS app for monitoring mph (I don't presently have any such thing installed)
3) Are we all independently arranging our own tow service? Seems like we could arrange for a tow service have a couple trucks ready ahead of time.

1) The PADT site.
2) I don't know. Do you have a portable GPS? If not, we can probably get one. You'll need to know your GPS starting and stopping position in LAT/LONG.

Now that you mention it, I do, but it's an old 1-channel collecting dust somewhere. The GPS on my Galaxy S3 is far superior. I'll investigate GPS apps - problem is there are 539 "GPS speedometer" apps an Android as of now so I was hoping for a recommendation.

P.S. Thanks for coordinating this!

 

[garygid]

Stoaty,
If you can get your GID-Meter to me, I will look at it to see if I can
find the problem.

Remind me, did I build it, or did you?
I will PM you momentarily.

 

[SierraQ]

I didn't catch if this was discussed, but what's the reason for covering the speedometer?

I don't think most people are used to looking over at GPS as their speedometer. Could add an element of danger. I'm unfamiliar w/the terrain, but wouldn't there be an issue of GPS speed deviating from actual speed of the car on inclines?

Anybody not familar or safe with GPS shouldn't participate. The GPS is the tool for measuring speed.

...

Tony, since you require GPS you need a checklist for the GPS to verify they will work as a primary speed measurement device. For example phone-based GPSes will likely need a 12V charger for car use to make sure the phone does not lose power (GPS tends to consume a fair amount of energy) and also to make sure the phone doesn't go to sleep. My phone (an iPhone) will sleep even with GPS running if not connected to power.

Having a mount for it would be ideal and safer too. Here is a cheap homemade version.

I suggest the following to be validated by the owner beforehand.

• 
  1. Verify the GPS displays speed constantly and quickly (some may only have average speed, others may have a significant delay)
  1. Verify that display will stay on for at least 10 minutes with GPS active and powered (phone-based GPSes only)
  1. Verify GPS has all the measurements you are requesting (lat/long coordinates, anything else?)
  1. Ideally provide some kind of mounting device to keep the display visible during the test.

I'd also like to throw out an alternative idea to avoid the need to cover up the eyebrow and speedometer. Use the GPS at the start to set 62 true miles per hour and then use whatever the equivalent is on the speedometer from that point on. If the speedometer is off it will be consistently off at a given speed so it can still be a valid reference +/- whatever it is offset. Just record what the offset is. (It would be an interesting point to record how much they are off just for grins--my Leaf displays +1 MPH at lower speeds for example.)

 

[DaveEV]

I'd also like to throw out an alternative idea to avoid the need to cover up the eyebrow and speedometer. Use the GPS at the start to set 62 true miles per hour and then use whatever the equivalent is on the speedometer from that point on. If the speedometer is off it will be consistently off at a given speed so it can still be a valid reference +/- whatever it is offset. Just record what the offset is. (It would be an interesting point to record how much they are off just for grins--my Leaf displays +1 MPH at lower speeds for example.)

+1. This seems much easier than relying on the GPS - one can pre-calibrate their car before-hand (make sure tire pressures are set to 36 psi cold before calibrating) and then use the GPS to confirm speed periodically through the test.

 

[GerryAZ]

To answer some concerns about speed--the cruise control in the Leaf holds the electric motor RPM constant by keeping the AC input power frequency steady at the desired setting. I use the cruise control a lot and the only time the speed varies is going down a steep hill if regeneration is not enough to hold the speed down (very rare situation). A slow-response GPS will show speed variation going up/down hills because of update rates and elevation calculation errors. A fast-response, high-accuracy GPS will show that the speed is constant up and down hills. I really like the way the Leaf cruise control holds the speed steady.

I was also concerned about using I-17 and I-10 in downtown Phoenix due to lack of adequate shoulders. I am looking forward to participating next Saturday, whatever route is chosen.

I had a flat tire yesterday. Does anyone in Phoenix have an original Ecopia with about 50% tread that they would like to sell?

Thanks,
Gerry

 

[palmermd]

I had a flat tire yesterday. Does anyone in Phoenix have an original Ecopia with about 50% tread that they would like to sell?

Thanks,
Gerry

It turns out there really is nothing wrong with the batteries...its just the tires wore down and we lost efficiency. haha

 

[TonyWilliams]

I will have one stock Ecopia wheel / tire. And a couple spares, since at least one car needs 2 tires swapped for the test.

Good ideas on calibrating, but I never actually considered using the phone GPS's. Far too many variables for me to consider.

Whatever device needs to show a Lat/Long. That is how we will know where you started and stopped.
Plus, speed, and yes, I guess we could calibrate to the LEAF speedo, then use that (expect 64mph indicated to equal 62 mph actual MPH on the GPS). I just see people making mistakes, and that will make that cars data invalid.

Yes, GPS needs to be mounted some way. I have several GPS's, mounts, etc. I'm sure others do, too.

 

[EricBayArea]

I have a suggestion for this test - although it may be too late.

How about finding a tuning shop and renting their dyno for a block of time. That way you can get up to speed, hit cruise control and let the batteries run down as far as you want without any worry of being stranded or having other variables affect you. The only thing that is not "real world" about this is rolling and wind resistance. However, the control aspect would be a huge plus. Since you are planning on about an hour each car you can try for a 4hr block. They typically have large fans to point at the car too to help with temperature.

 

[cwerdna]

Dyno's already been discussed before. See http://www.mynissanleaf.com/viewtopic.php?f=30&t=8802&p=220842&hilit=dyno#p220842" onclick="window.open(this.href);return false; and posts around there.

 

[EricBayArea]

Dyno's already been discussed before. See http://www.mynissanleaf.com/viewtopic.php?f=30&t=8802&p=220842&hilit=dyno#p220842" onclick="window.open(this.href);return false; and posts around there.

Didn't see those comments on the other thread. Oh well.

 

[shrink]

Loops:

PADT charging station is 0.3 miles from the freeway.

50.4 miles - BIG LOOP - 101 North, 202 East, South, West, then 101 North

40.4 miles - SMALL LOOP - 101 North, 60 East, 202 South, West, then 101 North

21.8 miles - LEFT LOOP - 101 North, 60 WEST, 10 South, 202 East, 101 North

LEAF's are expected to have ranges at 62mph of:

100% 12 bars - 84 miles (One Big Loop, One Small Loop - come up short by 6.8 miles)
85% 11 bars - 72 miles (One Big Loop, One Left Loop - close)
79% 10 bars - 66 miles (One Small Loop, One Left Loop - come up short by 6.2 miles)
73% 9 bars - 61 miles (Small Loop, Left Loop - close)
66% 8 bars - 56 miles (One Big Loop - pass by 5.6 miles)

Is there a way to check the elevation changes on the BIG LOOP? I live in central Phoenix and have driven East long that north part of the 202 to visit family in Mesa. It's a strain on the LEAF to do a roundtrip, although that's at 65 mph with A/C running. I've also biked that distance - from central Phoenix to Mesa on a path adjacent to that part of the 202. It was all uphill and tougher than I anticipated.

In general, I think central Phoenix is the lowest point in the Valley and I know for certain as you go north, the elevation increases. I think Chandler-Tempe-South Mesa-Gilbert is generally pretty level - i.e., the proposed SMALL LOOP (Edit: I meant the LEFT LOOP).

 

[cwerdna]

^^^
One can use Google Earth to determine elevation changes. See http://priuschat.com/threads/google-earth-can-give-you-an-elevation-profile-of-a-route-between-2-points.100653/" onclick="window.open(this.href);return false;. I actually learned about it here on MNL.

Side note: Re: GPS vs. speedometer w/elevation changes, I drove a little bit today w/my Garmin Nuvi 1200 comparing it to my Prius' speedometer on a road w/known elevation change (and some quite visible). I can say that my GPS unit is somewhat laggy to update its speed vs. my car's speedo. Also, there definitely can be a divergence of a few mph depending on whether you're going uphill or downhill.

I didn't have a chance to go up/down a steep hill.

 

[TonyWilliams]

I didn't have a chance to go up/down a steep hill.

Guys, we are not going up and down big hills. We don't need that data. If there are big hills (and frankly, I'm mostly blind here, as I don't know the area well), we MUST use a different route.

So, I ask that instead of figuring out if the automation handles hills well, or not, that we determine if these routes are useable.

Tony

 

[shrink]

^^^
One can use Google Earth to determine elevation changes. See http://priuschat.com/threads/google-earth-can-give-you-an-elevation-profile-of-a-route-between-2-points.100653/" onclick="window.open(this.href);return false;. I actually learned about it here on MNL.

Great tip. Thanks.

Tony, the starting elevation at PADT is 364 meters. The highest elevation I found along the BIG LOOP was 487 meters. That was on the 202 a few miles north of where it intersects with I-60 on the east end.

487-364 = 123 meter (403 feet) variation along that route.

Is that an issue?

The LEFT LOOP is pretty flat - seems to range from about 350 to 389 meters with most of the route around 360 meters.

 

[TonyWilliams]

I have a suggestion for this test - although it may be too late.

How about finding a tuning shop and renting their dyno for a block of time. .

No dynos, no running the battery down with the heater, no anything that isn't driving the maximum distance on like courses between cars. This is a demonstration, not a science project.

 

[cwerdna]

I had a flat tire yesterday. Does anyone in Phoenix have an original Ecopia with about 50% tread that they would like to sell?

Thanks,
Gerry

It turns out there really is nothing wrong with the batteries...its just the tires wore down and we lost efficiency. haha

On a related note, just as an FYI (I don't think anything about the test relating to tires needs to be changed) but worn vs. new tires can produce odometer reading differences. See http://www.tirerack.com/tires/tiretech/techpage.jsp?techid=177" onclick="window.open(this.href);return false;.

IMHO, the amount should be negligible in the results of this test.