jumpjack
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Re: i'er iChart: The iMiev Range Chart. ANY VOLUNTEERS?

Thu Jul 03, 2014 1:54 am

Thanks to this additional paper http://www.empa.ch/plugin/template/empa ... 16/---/l=1 I was able to draw a much more interesting chart:

Image

These are ranges in World Lightduty Test Cycle, both at standard temperature (23°C), winter temperature (-7°C) and summer temperature (35°C). It results that A/C requires around 1 kW, while heating arrives up to 4 kW!

Here we can also see how much inertia accounts in real range, as if you go at low speed, it means you're in town, and this mean continuous starts&stops; in this situation, up to 40% of the energy from the battery is used to accelerate car, and not all of this energy can be recovered by the Brake Recovery System: some of these systems have just 70% efficiency (=28% energy recovered), although I read about some reaching 90% (=36%).

At higher speeds (highway driving) actual range comes closer to max theoretical range.

Comparison between BRS present / not present:

Image

We can see here how BRS is "useless" in winter, as the percentage of energy recovered by the system is negligible w.r.t. energy "wasted" by heater.

So the black curve must be considered just as a major theoretical limit: by sure you'll be never able to go ABOVE that limit, but it is also sure you'll ussually be way below it.

From these charts I think we can conclude that minimum "guaranteed" range for iMiev is 45 km in heavy-traffic cities, where average speed is around 20 km/h, and 60km in "better" cities.

Although it could appear as a low range, actually it is ABOVE the 30 km which some studies state being the average daily-trip length for a typical driver (sorry, can't find a source).

JoeS
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Re: i'er iChart: The iMiev Range Chart. ANY VOLUNTEERS?

Thu Jul 03, 2014 6:44 am

jumpjack, thank you for this interesting update.

One of the many studies discussing typical daily driving distances is:
http://www.solarjourneyusa.com/EVdistanceAnalysis.php

Our i-MiEV satisfies most people's 'average' needs, and the modern first-generation EVs (Tesla excepted) were designed with this in mind. The problem we're seeing is in larger sprawling urban areas (e.g., Los Angeles, San Francisco Bay Area, etc. where round-trips of 100 miles (160km) are common) is that unavailability of guaranteed charging at a destination is resulting in the need to travel the longer distances round-trip on one charge. If the Leaf comes out with the rumored optional larger battery size, it will be interesting to see how many people will opt for it.

One of the problems I have with including A/C, heating, and BRS (regen) in any mileage range discussions is that those are uncontrolled variables; nevertheless, these graphs are good indications of their possible effect.
EVs: 2 Wht/Blu SE Prem., '13 Tesla MS85, 3 156v CorbinSparrows (2 Li-ion), 24v EcoScoot(LiFePO4)
EV Conv: 156v '86 Ram PU, 144v '65 Saab 96
Hybrids: 48v1kW bike
ICE: '88 Isuzu Trooper. Mothballed: '67 Saab (orig.owner), '76 MBZ L206D RHD RV

HParkEV
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Location: Toronto, Ontario

Re: i'er iChart: The iMiev Range Chart. ANY VOLUNTEERS?

Fri Jul 04, 2014 6:39 am

Jumpjack, those charts are excellent! This is exactly what I wanted to see for a long time - they show what are the most efficient speeds (giving the longest range) depending on various conditions and loads.
It looks like with all accessories off, about 20km/h (13mph) is the most efficient, with A/C on about 32km/h (20mph) and with heating on 55km/h (35mph) are the most efficient speeds. This is especially useful to know in the wintertime for us northerners, that slowing down below 35mph with the heat on is not getting you any more range, actually less.

I think the previous graph which basically shows all EV's as most efficient at 22.5km/h is very inaccurate. I would speculate that a Model S most efficient speed would be about double what the most efficient speed would be for an i-MiEV, considering all the Tesla's electronic gadgetry and its slippery shape. Most other production EV's would probably fall in between.

Thanks for the research!
2012 Ocean Blue SE (premium) Canada-spec
02/2012 production, 06/2013 delivery
Upgraded EVSE

DaveMiller
Posts: 58
Joined: Thu Sep 12, 2013 4:16 am
Location: Normal IL

Re: i'er iChart: The iMiev Range Chart. ANY VOLUNTEERS?

Fri Jul 04, 2014 8:49 am

Great chart! Thank you. Any chance you could make another copy in mph?

Thanks, Dave

jumpjack
Posts: 27
Joined: Fri Nov 22, 2013 2:04 am

Re: i'er iChart: The iMiev Range Chart. ANY VOLUNTEERS?

Fri Jul 04, 2014 11:04 am

HParkEV wrote:Jumpjack, those charts are excellent! This is exactly what I wanted to see for a long time - they show what are the most efficient speeds (giving the longest range) depending on various conditions and loads.
It looks like with all accessories off, about 20km/h (13mph) is the most efficient, with A/C on about 32km/h (20mph) and with heating on 55km/h (35mph) are the most efficient speeds. This is especially useful to know in the wintertime for us northerners, that slowing down below 35mph with the heat on is not getting you any more range, actually less.

I think the previous graph which basically shows all EV's as most efficient at 22.5km/h is very inaccurate. I would speculate that a Model S most efficient speed would be about double what the most efficient speed would be for an i-MiEV, considering all the Tesla's electronic gadgetry and its slippery shape. Most other production EV's would probably fall in between.

Thanks for the research!

Of course it's not my research,it's just my chart. ;)
About the maximum range, it depends on the standby power consumption, which is not knwon unless somebody measures it, but I think it's very tricky to disconnect the traction battery of an EV...
So I consider 300W for all vehicles, which by sure is not true. But with the interactive chart you can change this value as you like.
I know A/C and heating consumption only for iMiev, but maybe this datum can be found also for other vehicles? I think I read it for the Smart ED in its manual months ago.

Later I'll publish both MPH version of the chart and raw data.

Don
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Re: i'er iChart: The iMiev Range Chart. ANY VOLUNTEERS?

Fri Jul 04, 2014 11:52 am

I didn't read the source data behind the graphs - Do you know if the Peukert Effect was taken into consideration?

Don
2012 iMiEV SE Premium, White
2012 iMiEV SE Premium, Raspberry Metallic
2012 iMiEV SE, White
2017 Chevy Volt Premier
2014 Ford Transit Connect XLT SWB wagon

jumpjack
Posts: 27
Joined: Fri Nov 22, 2013 2:04 am

Re: i'er iChart: The iMiev Range Chart. ANY VOLUNTEERS?

Fri Jul 04, 2014 1:49 pm

Don wrote:I didn't read the source data behind the graphs - Do you know if the Peukert Effect was taken into consideration?

Don

Peukert effect is negligible in lithium batteries: discharge them at C20 or C2, and you'll get same capacity.

Lead:
Image


Lithium:
Image

But maybe you were thinking to coulombic efficiency, i.e. ratio betweeen energy you actually store in the battery and energy you get from grid; this is a good point.
My charts do not take into account coulombic efficiency, but some data are available in the paper: it's between 75% and 80%, which means you need 1 kWh from grid to put 800 Wh in the battery.
I'll study this.
In the meantime, here it is mph chart:
Image
Last edited by jumpjack on Fri Jul 04, 2014 2:57 pm, edited 4 times in total.

DaveMiller
Posts: 58
Joined: Thu Sep 12, 2013 4:16 am
Location: Normal IL

Re: i'er iChart: The iMiev Range Chart. ANY VOLUNTEERS?

Fri Jul 04, 2014 2:20 pm

Thank you for the mph version, but I think the velocity scale is incorrect. My I-Miev will not go 200 mph.
Dave

jumpjack
Posts: 27
Joined: Fri Nov 22, 2013 2:04 am

Re: i'er iChart: The iMiev Range Chart. ANY VOLUNTEERS?

Fri Jul 04, 2014 2:37 pm

DaveMiller wrote:Thank you for the mph version, but I think the velocity scale is incorrect. My I-Miev will not go 200 mph.
Dave

Yes, I put a * rather than a /...

jumpjack
Posts: 27
Joined: Fri Nov 22, 2013 2:04 am

Re: i'er iChart: The iMiev Range Chart. ANY VOLUNTEERS?

Fri Jul 04, 2014 2:39 pm

And these are the sad charts taking into account coulombic efficiency...

Image

edit:
damn imperial units... X axis was wrong too. Now it should be ok in all images.

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