EV1 Range Graphs for Alec Proudfoot's EV1

Updated 8-Jul-98

Graphs up to total mileage of 2810

Estimated Range vs. total mileage

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Notes:

Range is calculated as trip miles/percentage charge used during trip. Prior to mile 293, range was estimated only for trips where there was a full recharge and was calculated as trip miles + estimated range remaining on dashboard indicator.

An average of estimated range for the previous 5 trips is shown to make trends easier to spot.

Actual trip mileage is also shown. The longer the trip, the more accurate the 100% estimated range figure will be.

If bars were used to estimate percentage charge remaining because the 120V convenience charger was used, percentage charge was estimated to be in the middle of the range for that bar, where each bar represents 9% (i.e. if 3 bars show, then percent remaining is 2*9% + 4.5% = 22.5%). This will obviously be less accurate than if the exact percentage charge remaining is available. The number of times the charge was estimated from bars is shown to indicate which estimates may be less accurate.

The high range of 76.6 miles at ODO reading 1429 is almost certainly due to an error in reading the bar indicator (a starting bar reading of 5 insteading of 4 gives a much more normal 53.2 miles range for this data point).

Estimated air temperature is just a rough estimate of the temperature during the majority of the trip (probably only good to within +-15 deg F). Someday I may replace or augment this with real average temperature data for San Jose (anyone know a good on-line source for this?)

Estimated Range vs. HVAC usage

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Notes:

This surprising result is probably due to less AC use during short trips (i.e. lots of stop and go driving) vs. long trips (efficient freeway driving). It is impossible to completely separate the variables here, at least not with the amount of data available so far.

Estimated Range for City and Highway Driving

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Notes:

City driving is defined as 90% or more city driving (i.e. stoplights), Highway is defined as 90% or more highway (i.e. freeway with no stopping) and anything in between is City and Highway.

Estimated Range vs. Driving Style

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Notes:

No surprises here. Heavy driving style is many fast accelerations (usually lost of test drives) and/or very fast driving (75mph or more).

Estimated Range vs. Terrain

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Notes:

This surprising result is due to the slower speeds and thus less drag for the really hilly drives. All trips between recharges have so far been essentially 0 overall altitude gain. The EV1 is very good at recovering energy with regen on the way back down the hill, so if there is no overall altitude gain for a trip, the effects of speed on range dominate.

View Raw Data used for these graphs (Excel 7.0 Worksheet)

View some original Impact prototype photos

Average Miles/trip = 21.5

Average # legs/trip = 2.9

Average # mi/leg = 7.7

Average Estimated Range:

All trips		47.46mi	n=112
City		42.5	n=50
City+Hwy	48.4	n=38
Highway		56.2	n=16

Average Range with AC useage:

0%used	46.7mi	n=63
25%	46.5	n=14
50%	49.4	n=13
75%	50.2	n=6
100%	49.8	n=9

Average Range with Driving Style:

Easy	50mi	n=69
Medium	44.3	n=36
Hard	32.5	n=4

Average Range with Terrain:

Flat		47.1mi	n=97
Medium	47.8	n=11
Hilly	54.1	n=4

Explanation of Methodology

I picked up the car with 91 miles on the odometer. At first, I did not record % charge remaining (I did not have regular access to a 240V charger up to an odometer reading of 363 miles), or bars remaining. Therefore, the estimated range up to 293 miles ODO reading was only calculated if the previous recharge had been a full one, and range was estimated as trip miles + estimated miles remaining. (Note that due to the way Excel graphs things, trips in between full charges up to 293 miles ODO are shown as 0 miles range since there was no data for estimated range in these cases. These 0 mile range data points are not included in any average range data.)

Starting with 293 miles, I recorded start and end bars of charge (11 is full, each bar is 9%), and at 363 miles I started recording start and end % charge if a 240V charger was used. Estimated range was calculated using either the % indication on the 240 V charger or bars remaining if the 120V charger was used. The Estimated Range was then calculated using the trip miles divided by the percentage of charge used. If bars were used because percentage charge was not available, then it was assumed that the percentage charge was in the middle of the range for that bar. For example, total percentage charge used if start charge was 78% and end bars were 3 would be: 78% - ((2*9%)+4.5%) = 55.5%. Start charge for all cases when the charge was a full charge was assumed to be 99%

I have also collected a lot of other information in addition to start and end charge info and mileage. These are all the items I eventually began recording for each trip:

(City/Highway driving and AC stats were collected starting at mile 421.)

You canView Raw Data here (Excel 7.0 Worksheet)

Possible sources of error:

E-mail me!alec@netcom.com