Miles per Bar/ Range / Trip Planning Discussions

[mdbuilder]

Sounds doubtful @75, the 2000 foot (nearly) altitude gain is going to kill you at high speed.

 

[rkarl89203]

NEMA-14-50 at RV parks is basically L2 charging in effect.
The problem of course is cost.
I have talked with many RV parks while planning my 5,000 mile trip and there is no common rate.
Some a $5.00 a session, some will charge for an entire nights stay. I have talked with KOA campgrounds which have offered a $10.00 total charge and one nearby here in Rockford that is charging $5 an hour.
Wow.
But they are there in an emergency. I

 

[Don]

Assuming a highway trip at 75 mph, then by your table the maximum travel distance for a full pack would be 44.8 miles. Now to add an additional variable, elevation. The elevation of Anthem, Arizona, is 1,863 per wikipedia. The elevation of Cordes Junction, Arizona, is 3,700 feet. Plugshare says its 34 miles on I-17 between Anthem and Cordes Junction and there is some up and down, so some regen is possible. There are no other realistic alternative routes for making the trip. Can I make it, or do I stop in Black Canyon City and use a NEMA 14-50 campground charge to re-charge?

Or do I just drive at 70 or less and risk aggravating the other drivers? (Driving at 70 by your table gets me 49.6 miles).

Using his table, slowing from 75 to 65 gets you 56 miles of range instead of only 45. Nobody is going to be aggravated by a car doing 65 on the freeway . . . . you'll probably get passed by many, but you'll probably pass a few yourself

FWIW, when I'm on the freeway with one of our iMiEV's, I always do 65 . . . . or a little less, and I'm not challenged to get the best range - Our freeway trips are all 30 miles round trip or less

Don

 

[rkarl89203]

Is there a huge advantage then to do 55 on a freeway when you have many lanes ?
Or is the difference negligible as per 55 or 60?..
We are just trying to get a happy medium.

 

[kiev]

... The elevation of Anthem, Arizona, is 1,863 per wikipedia. The elevation of Cordes Junction, Arizona, is 3,700 feet. Plugshare says its 34 miles on I-17 between Anthem and Cordes Junction and there is some up and down, so some regen is possible. There are no other realistic alternative routes for making the trip. Can I make it, or do I stop in Black Canyon City and use a NEMA 14-50 campground charge to re-charge?

Or do I just drive at 70 or less and risk aggravating the other drivers? (Driving at 70 by your table gets me 49.6 miles).

Best guesses accepted!

:?:

Yes you can make it. The average gradient is 1% so you will lose range. But i think you can make it if you drive 60 on the flats and slower up the hills. Put your emergency flashers on--then folks will just see you and pass without aggravation. If you are going slow without the flashers then you deserve to suffer shame.

 

[GdB]

I have an excel spreadsheet I used to figure this out and I thought this little table would be useful:

Assuming little or no AC, and no heater!

MPH miles/bar
25 9.5
30 8.6
35 7.6
40 6.7
45 5.9
50 5.1
55 4.5
60 4
65 3.5
70 3.1
75 2.8
80 2.5

Assuming a highway trip at 75 mph, then by your table the maximum travel distance for a full pack would be 44.8 miles. Now to add an additional variable, elevation. The elevation of Anthem, Arizona, is 1,863 per wikipedia. The elevation of Cordes Junction, Arizona, is 3,700 feet. Plugshare says its 34 miles on I-17 between Anthem and Cordes Junction and there is some up and down, so some regen is possible. There are no other realistic alternative routes for making the trip. Can I make it, or do I stop in Black Canyon City and use a NEMA 14-50 campground charge to re-charge?

Or do I just drive at 70 or less and risk aggravating the other drivers? (Driving at 70 by your table gets me 49.6 miles).

Best guesses accepted!

:?:

You can optimistically estimate about 1 bar per 1000 ft:

The equation for this is:
https://en.wikipedia.org/wiki/Potential_energy
U=mgh (Ignoring energy losses, which are small for the i-miEV, maybe around 10%?)

I calculated with 1 person, (2550 lbs total), 17000ft:
SI units to simplify:
(2550/2.2)*9.8*5165 = 58666666 KJ
Which converted to kw-hr is 16.3 kw-hr.

 

[Don]

Is there a huge advantage then to do 55 on a freeway when you have many lanes ?
Or is the difference negligible as per 55 or 60?..
We are just trying to get a happy medium.

The loss of range accelerates much faster than your speed - The loss of range caused by adding 5 mph from 50 to 55 mph is much less than the loss caused by adding 5 more mph to get you to 60 and it gets even worse each time you add 5 more

As always, limit speed as you need to in order to have a safe margin to get you where you need to go - If you have 8 bars remaining and it's only 10 miles to home, drive 75 if you need to, but if the required range is ever in doubt, slow down until you know for sure you can make it safely on the power you have left - Range can be whatever you need it to be, within reason and if you plan properly, you'll never have a problem

Don

 

[Phximiev]

I have an excel spreadsheet I used to figure this out and I thought this little table would be useful:

Assuming little or no AC, and no heater!

MPH miles/bar
25 9.5
30 8.6
35 7.6
40 6.7
45 5.9
50 5.1
55 4.5
60 4
65 3.5
70 3.1
75 2.8
80 2.5

Assuming a highway trip at 75 mph, then by your table the maximum travel distance for a full pack would be 44.8 miles. Now to add an additional variable, elevation. The elevation of Anthem, Arizona, is 1,863 per wikipedia. The elevation of Cordes Junction, Arizona, is 3,700 feet. Plugshare says its 34 miles on I-17 between Anthem and Cordes Junction and there is some up and down, so some regen is possible. There are no other realistic alternative routes for making the trip. Can I make it, or do I stop in Black Canyon City and use a NEMA 14-50 campground charge to re-charge?

Or do I just drive at 70 or less and risk aggravating the other drivers? (Driving at 70 by your table gets me 49.6 miles).

Best guesses accepted!

:?:

You can optimistically estimate about 1 bar per 1000 ft:

The equation for this is:
https://en.wikipedia.org/wiki/Potential_energy
U=mgh (Ignoring energy losses, which are small for the i-miEV, maybe around 10%?)

I calculated with 1 person, (2550 lbs total), 17000ft:
SI units to simplify:
(2550/2.2)*9.8*5165 = 58666666 KJ
Which converted to kw-hr is 16.3 kw-hr.

Ok, so for 2,000 feet or so of increased altitude, then two bars+.

Ok, so I use the table for let's say 70 mph then its 3.1 times (16 - 2) = 43 miles and I should make it. If I use 3 bars for altitude then I can get 39 miles, and still make it, but its close. This also assumes that I "married" the two tables together correctly.

 

[kiev]

So it looks like you want to make a speed run as fast as possible without stopping to charge along the way--i say go for it, try to run at 75 and you should be able to make it 34 miles, but you will be down to the blinking fuel guage with 0 or 1 bar showing at the end. The power needle will be pointing straight up the whole way. It's a sporty proposition, sounds like fun too, i like it!

Hey when are you going to make this run--be sure to post the details and results. i hit the interstate today and had the needle up around 60-70 Amps just to go 70mph on a flat section, 3 people in the car and A/C on. At that rate you only have about 30 minutes of driving available.

 

[Phximiev]

I made the first test run to the Outlets at Anthem last night. Left at 7:00 pm or so, 85 degrees, no heat and no ac used.

Altitude: Home, 1,100 or so; Anthem, 1,863; change of approximately 800 feet.

To Anthem uphill on I-17: arrived at 7:25 pm; 23.2 miles; # of bars used: 8; miles per bar: 2.9; speed 60 to 65 mph, with an occasional 70 mph spurt due to traffic pressure. The speed limit starts at 65 and increases to 75 about 10 miles out.

Recharged 4 bars at the Blink at Anthem (Unit 102697), which took 1 hour and 17 minutes. Checked in and posted a picture! Also took a picture of the tallest Christmas tree in the world!?!

To home downhill on I-17: 23.4 miles; # of bars used: 6; miles per bar: 3.9, speed 60 to 65 mph.

Trip average: 46.6 miles, 14 bars used, average mpb 3.3.

Remaining distance to Black Canyon City from Anthem (elevation 2,000): 16 miles; expected number of bars to be used: 5.5 (16 divided by 2.9). Expected total usage to get to Black Canyon City from home: 13.5 bars, which would require 4 hours+ to recharge to full, return usage 10.1 bars.

Summary:

The charts above are in line with the above except that I believe that the altitude adjustment may be low. The steeper the hill, the greater the hit, as would be expected. A stop in Anthem on the way to Black Canyon City would ease the range issue quite a bit.

 

[mdbuilder]

So, as I said

Sounds doubtful @75, the 2000 foot (nearly) altitude gain is going to kill you at high speed.

No go @ 75 .

 

[Phximiev]

So, as I said

Sounds doubtful @75, the 2000 foot (nearly) altitude gain is going to kill you at high speed.

No go @ 75 .

Per the table at 75, one gets 2.8 miles per bar on the straight and level. I averaged 3.3 mpb at 60 to 65 round trip to Anthem, which is slightly less (.2) than the table shows at 65. On the Anthem test, I lost .4 miles per bar (to 2.9 mpb from the round trip average of 3.3 mpb) due to altitude. At 75, assuming the same adjustments, 2.2 mpb is the result with total pack mileage being 35.2. The trip to Black Canyon City is 39 miles and so out of range at 75 mph. A stop in Anthem though would make it easy.

The trip to Cordes Junction at this point (to avoid any gut renching experiences) requires a stop in both Anthem (1 hour and 17 minutes for 4 bars) and Black Canyon City (probably 2 hours for 6 bars). The trip between Black Canyon City and Cordes Junction is reduced to 18 miles which is doable.

The Anthem stop could be occupied with a coffee/snack and window shopping break. The 2 hours in Black Canyon City could be occupied with a hike.

The downside of course is that we would be: (1) using a city car for traveling, (2) expanding the trip from a 1 hour+ to 4 hours+, and (3) providing wifey with the question of why not rent the Volt again to avoid the whole problem in the first place?

Hmm, I'd still like to climb the mountain tho. And try that portable Chademo thingy also.

 

[kiev]

what about slowing down to 55 and turn on your flashers if you're worried about the traffic?

 

[Phximiev]

what about slowing down to 55 and turn on your flashers if you're worried about the traffic?

I-17 is not a road where I would slow down that much. Its too dangerous. 5 to 10 below the speed limit (65 to 75) is pushing it as it is.

 

[Don]

So. . . . every overloaded semi on I-17 going uphill is somehow able to do a minimum of 65 mph??

Get in front of the slowest truck you can find and pace him - Keep him a steady 100 yards behind you and you're not gonna get run over

Don

 

[mdbuilder]

FWIW, as one who will steam up your *** in the left lane with the cruise set at 85 going up a 6% grade - have no issue with anyone going as slow as they want in the right hand lane

 

[kiev]

Or get behind the slow truck and use the draft--let him break the wind before you and the car will be in regen going uphill...

 

[PV1]

Find yourself a pickup or SUV to draft (that is, if any of them are doing less than 80 :lol: :roll: ). You get the mileage boost without the turbulence. It's too dangerous to get in the slip stream of a semi, and even a half-crazy following distance puts you right in the turbulence. Any further back, you're not saving much.

But I would definitely pace ahead of a semi to defend from passing traffic. Doesn't work too well if you're blocking traffic from the back of the truck :? .

 

[JoeS]

Or get behind the slow truck and use the draft--let him break the wind before you and the car will be in regen going uphill...

+1

Oh, boy, this discussion has gone off-topic and has split into two separate topics but when I thought I could separate them and start new threads it became too messy (but I still may do that...).

The two topics are:

1) Phximiev trip planning
2) Highway hypermiling techniques and 'safety'

I submit there's a third topic: Trip Time Optimization, taking stopping for L2 charging into account.

TRIP PLANNING
This, to me, is the fun part of planning a longer i-MiEV trip, very reminiscent of a marine navigator preparing for an ocean or coastal passage or a pilot preparing for a flight. Phximiev, I looked on the map and identified the locations you are talking about. Without necessarily divulging your home's location, can you give us a fairly exact starting point and end point for your trip? This will enable us to do some fairly accurate analyses.

HIGHWAY HYPERMILING
This, in my opinion, is the best road sign on US highways (this one is from Colorado):

Having spent over 100K miles hypermiling my Gen1 Honda Insights and being rear-ended and the car totalled by a drunk driver, I have some very strong opinions on this topic.

Here is a detailed discussion as it affects the i-MiEV:
http://myimiev.com/forum/viewtopic.php?f=28&t=287&p=20148 (go to my January 21, 2015 post)

Here is a description of the accident:
http://www.insightcentral.net/forum...ion/46929-insight-mima-gets-crashed-into.html

My follow-up post there:
http://www.insightcentral.net/forum...nsight-mima-gets-crashed-into.html#post506729

I hate having trucks following me, as in an emergency I can stop faster than they can and if they hit me I'm dead meat. My present position on this whole topic is that following a truck is safer than driving naked at the same speed because of the visual 'wall' the truck represents to someone coming from behind. How closely one follows a truck has too many variables (safety, legal, aero, etc., including the consideration for a chipped windshield), so I'm not going there.

TRIP TIME OPTIMIZATION
I think a long trip in an iMiEV with only L2 charging along the way merits a discussion. If, by driving slower, you can make it to a destination and then plug the car in while you do something else at that destination, this is preferable to driving fast but having to stop for an hour or so at an intermediate charging point (and cooling your heels) on your way to that destination. I think Phximiev's example will be interesting to continue analyzing, especially with the variable of altitude thrown in. To be continued...

 

[Phximiev]

Phximiev, I looked on the map and identified the locations you are talking about. Without necessarily divulging your home's location, can you give us a fairly exact starting point and end point for your trip? This will enable us to do some fairly accurate analyses.

Orangewood and I-17 would be a sufficient start and end position. Sometime over the next week or so, I plan on going to Black Canyon City. There are 3 RV camps there with 14-50 outlets. However, I have to call them and see if they are amenable to a EV charging there (for a fee of course). I also have to find out if I should bring (or they have) a surge protector.

I have called one locally and they weren't amenable.