jray3
Posts: 1564
Joined: Tue Dec 06, 2011 1:05 am
Location: Tacoma area, WA
Contact: Website

Miles per Bar/ Range / Trip Planning Discussions

Thu Apr 25, 2013 2:47 pm

I know that this has been discussed at length, but the search function is so lousy that I didn't find a decent thread to resurrect. (where is that thread where we were posting RR meter photos?)
So, now that Spring has finally sprung in the Northwest, with multiple days in a row in the 60's, I'm remembering what easy living is like. The wife's mellow motoring has always gotten better range than Yours Truly, but we were both amazed when her 24 mile outbound commute, which is a combination of traffic jam and 60 mph highway, consumed only 4 bars, after requiring 6-7 bars all winter with occasional defrost only. This was a tag-team commute, so the battery was already 'warmed up' by my 16 mile return home. At 6 miles/bar(kWh), that'd be a range of 96 miles and efficiency of 167 watt-hrs per mile, or 55% better than the EPA rating. :mrgreen:
2012 i-SE "MR BEAN" 93,000 miles
2000 Mazda Miata EV, 78 kW, 17 kWh
1983 Grumman Kurbwatt EV,170 kW, 32 kWh
1983 Mazda RX-7 EV 43 kW 10 kWh
1971 "Karmann Eclectric" EV 240 kW 19 kWh
1965 Karmann Ghia Cabriolet

randy3
Posts: 17
Joined: Sun Apr 21, 2013 12:05 pm

Re: Miles per Bar/ Range discussions

Thu Apr 25, 2013 2:53 pm

Are the bars (rr bars, I think you called them) all of equal value on the iMieV? In other words, all else being equal, will the top bar give the same miles as the middle and bottom bars?
Randy
Fresno, CA
2012 Mitsubishi i-MiEV, Raspberry

jray3
Posts: 1564
Joined: Tue Dec 06, 2011 1:05 am
Location: Tacoma area, WA
Contact: Website

Re: Miles per Bar/ Range discussions

Thu Apr 25, 2013 3:40 pm

randy3 wrote:Are the bars (rr bars, I think you called them) all of equal value on the iMieV? In other words, all else being equal, will the top bar give the same miles as the middle and bottom bars?


Yes, they're supposed to each be the same amount of energy, one usable kWh. It often seems like the first bar lasts longer than the rest, but I think that's because the first bar is usually consumed at lower speeds. I logged the odometer readings for each bar on a wintertime trip, and got 4.8 and 6.1 miles/kWh on the first two bars, but only 2.3 to 3.9 miles/kWh on the next 11 bars. Guess which portion of the trip was on the highway!
2012 i-SE "MR BEAN" 93,000 miles
2000 Mazda Miata EV, 78 kW, 17 kWh
1983 Grumman Kurbwatt EV,170 kW, 32 kWh
1983 Mazda RX-7 EV 43 kW 10 kWh
1971 "Karmann Eclectric" EV 240 kW 19 kWh
1965 Karmann Ghia Cabriolet

Don
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Location: Biloxi MS

Re: Miles per Bar/ Range discussions

Thu Apr 25, 2013 4:30 pm

Don't think you can say that since one fuel gauge bar gave you 'X' miles, then the total range is 16 times 'X' - It's not that kind of meter

I too have noticed that the first bar always gives me more miles than any other, even though any trip I take begins with the first 3 miles at an average of 45 mph - The second bar never gives me as many miles, even though that bar is usually done at more like 30 mph

I'm not sure if the meter uses a combination of measured pack voltage and watts consumed, but that would seem logical. Remember that a deep discharge followed by a full recharge recalibrates that meter. It's intended to be a 'fuel gauge' and just as any gauge on an ICE isn't completely linear (first 1/4 tank gives you 100 miles, but your actual range probably isn't really 400 miles) it doesn't seem like our meter is completely linear either

I seldom look at it, but usually do check the RR meter when I have 8 bars left - 'Normal' for me is about 40 miles left it seems

There *are* those who have driven this car an actual 100 miles on a single charge - Not that hard to do if you're in an urban environment where you're seldom above 35 or so

Don
2012 iMiEV SE Premium, White
2012 iMiEV SE, White
2017 Chevy Volt Premier
2014 Ford Transit Connect XLT SWB wagon, 14,000 miles
1979 Honda CBX six into six

randy3
Posts: 17
Joined: Sun Apr 21, 2013 12:05 pm

Re: Miles per Bar/ Range discussions

Thu Apr 25, 2013 4:51 pm

Thanks. I'm hoping the i-MieV is more straightforward than the LEAF.

When I first got the LEAF, driving steady, the top bar would get me about 4 miles, then the other bars would get about 7 miles (12 bars total). Then they redid the software for it. Months later, I'm still not used to the change. The top bars disappear really quick and bottom bar is like a double bar. I'm looking forward to having each bar be a little more equal.

Nissan also put a second row of bars (small ones) right next to the longer (like rr) bars. These show how much your battery has degraded. Those bars (battery capacity bars) have caused considerable heated discussion among LEAF owners. In 2.5 years, my LEAF has lost one capacity bar, but I don't really understand if that means it's capacity is down 6%, 8% or 15%, and Nissan reps don't tell me.
Randy
Fresno, CA
2012 Mitsubishi i-MiEV, Raspberry

jray3
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Location: Tacoma area, WA
Contact: Website

Re: Miles per Bar/ Range discussions

Fri Apr 26, 2013 10:12 am

Great to see you here Randy. Very few folks own both a LEAF and an i, so your perspective will be valuable. I prefer the i for local errands and my commute EVen after driving a lot of carpools in friends' Leaves. I think that the SOC meter is counting more than just amp-hours, because if it was, the miles per kWh would steadily decrease as the charge is depleted. (Takes more amp-hrs to make a kWh as voltage decreases). Even if all the Coulombs are being counted, no meter is perfect, so I don't feel bad about getting below 2 bars o charge for a rebalancing slightly more often than the once per year now recommended in our maintenance schedule.....
2012 i-SE "MR BEAN" 93,000 miles
2000 Mazda Miata EV, 78 kW, 17 kWh
1983 Grumman Kurbwatt EV,170 kW, 32 kWh
1983 Mazda RX-7 EV 43 kW 10 kWh
1971 "Karmann Eclectric" EV 240 kW 19 kWh
1965 Karmann Ghia Cabriolet

JoeS
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Re: Miles per Bar/ Range discussions

Fri Apr 26, 2013 11:10 am

jray3 wrote:I know that this has been discussed at length, but the search function is so lousy that I didn't find a decent thread to resurrect. (where is that thread where we were posting RR meter photos?)...
jray3, know what you mean. Found it: maximum range remaining. This should prove of interest so some of our newer members where the challenge still stands: show us a photo of your RR (Range Remaining numeric) readout that exceeds the presently-claimed record by TaosEV of RR=103 miles (166km). http://myimiev.com/forum/viewtopic.php?p=2290#p2290

As far as fuel-gauge non-linearity, after getting to the sixteenth bar the iMiEV absorbs not only the (roughly) 1kWh but also the additional energy during balancing, and perhaps that reflects some additional distance for it to drop the first bar? In my case, I'll never know because my first 4 miles are all downhill and the fuel gauge sometimes stays at the full 16 bars well over the first 10 miles.

As far as non-linearity at the bottom end, comparing the miles driven to bar depletion I haven't noticed any significant difference: perhaps it's just a little bit of concern beginning to set in as one gets down there? If anything, it should stretch out because we unconsciously ease up a bit?
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
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RobbW
Posts: 417
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Location: Elgin, IL

Re: Miles per Bar/ Range discussions

Fri Jul 19, 2013 10:02 am

I understand that the bars and miles do not have an exactly linear relationship, but any guess as to how far off the two are? Joe, it sounds as though you don't believe there is that big of a difference. Would that mean, in general, we could probably take the miles driven divided by the bars used to get an average miles per bar and "roughly" apply that to all the bars?

On my way in to work this morning, I measured exactly the miles driven over the entire course, 15.3 miles. Once I parked at work, I saw that two bars had been used. Granted, I have no idea if the second bar had just dropped off or if it was very near to dropping the third bar or halfway between. In any case, doing the math and assuming a linear relationship (which it isn't), I would get roughly 7.5 miles per bar if I continue driving in the same style as I did this morning. Being kind of iffy on the state of the 2nd/3rd bar, my total range on this charge would be anywhere between 80 miles and 120 miles. Obviously, it most likely is NOT going to be close to 120 miles, but if I can safely assume 80 miles on the low end, I would be happy with that.
Clear Skies,
Robb

EV: 2012 Mitsubishi i-MiEV SE, Raspberry Metallic, Premium Package - Purchased 07/11/13
PHEV: 2017 Chrysler Pacifica eHybrid, Bright White, Platinum Package - Purchased 05/01/17

RobbW
Posts: 417
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Location: Elgin, IL

Re: Miles per Bar/ Range discussions

Fri Jul 19, 2013 11:23 am

Okay, so it turns out it was closer to dropping the third bar as it did so shortly after I headed out for lunch. So, in a linear world, this should equate to roughly 5 miles per bar, or 80 miles per charge.

I also understand there is not a very good correlation between the power bars and the RR gauge. However, another fun little game I've found myself enjoying is how far can I drive while keeping the RR at the same mile?!
Clear Skies,
Robb

EV: 2012 Mitsubishi i-MiEV SE, Raspberry Metallic, Premium Package - Purchased 07/11/13
PHEV: 2017 Chrysler Pacifica eHybrid, Bright White, Platinum Package - Purchased 05/01/17

Don
Site Moderator
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Location: Biloxi MS

Re: Miles per Bar/ Range discussions

Fri Jul 19, 2013 12:25 pm

RobbW wrote:I understand that the bars and miles do not have an exactly linear relationship, but any guess as to how far off the two are? Joe, it sounds as though you don't believe there is that big of a difference. Would that mean, in general, we could probably take the miles driven divided by the bars used to get an average miles per bar and "roughly" apply that to all the bars?
That would give you an average 'range per bar' . . . . but it still wouldn't tell you anything about how far you can drive on any one given bar. If you were going rapidly uphill, you might only get one mile to the bar, whereas if you were driving slowly downhill, you might get 30 miles

I generally don't watch the 'gas gauge' to check the bars very often just for this reason. The RR display at least gives you an educated calculation based on how and where you've been driving for the past 15 miles, so it's much more useful to me. I almost always glance ad the 'gas gauge' when the RR reads 40, and almost always see 8 bars remaining . . . . sometimes 9 bars just getting ready to switch to 8. On average, one bar equals 5 miles of range for me . . . . but the next bar might take me 2 miles or 15 - No predicting

Don
2012 iMiEV SE Premium, White
2012 iMiEV SE, White
2017 Chevy Volt Premier
2014 Ford Transit Connect XLT SWB wagon, 14,000 miles
1979 Honda CBX six into six

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