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 Post subject: Redlands to Forest Falls
PostPosted: Mon Mar 27, 2017 11:54 pm 
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Joined: Mon Oct 01, 2012 9:46 pm
Posts: 18
Location: Redlands, CA
Here are some Fit EV performance numbers from a trip up into the San Bernardino Mountains today. Total elevation change was 4,800’. Round trip distance was 39.5 miles and overall “mileage” was 5.6 miles/kwh (as measured by trip meter “B”). No use of A/C or heat. No charging along the way. No passengers or luggage. Just as a side note, Redlands Mountain Grove Plaza has 8 ChargePoint L2 charging stations. A good spot to recharge that’s seldom ICEd out.

Leg 1: Redlands Mountain Grove Plaza (1,200’) to Highway 38 Forest Falls turnoff (4,500’)
Temperature: 75 degrees
Distance: 15.5 miles
Elevation change: +3,300’
Initial state of charge: 99%
State of charge on arrival: 57%
Efficiency: 2.3 miles/kWh

Leg 2: Highway 38 Forest Falls turnoff (4,500’) to Big Falls parking area (6,000’)
Temperature: 57 degrees
Distance: 4.2 miles
Elevation change: +1,500’
Initial state of charge: 57%
State of charge on arrival: 41%
Efficiency: 1.6 miles/kWh

Leg 3: Big Falls parking area (6,000’) to Redlands Mountain Grove Plaza (1,200’)
Temperature: 51 degrees
Distance: 19.7 miles
Elevation change: -4,800’
Initial state of charge: 41%
State of charge on arrival: 56%
Efficiency: 99.9 miles/kWh (as indicated by trip meter “A”; what it shows when there is a net gain in energy for the trip)


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 Post subject: Re: Redlands to Forest Falls
PostPosted: Wed Mar 29, 2017 11:53 am 
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Joined: Mon Oct 01, 2012 9:46 pm
Posts: 18
Location: Redlands, CA
In the above measurements, I used the trip meters to record the distance and efficiency (miles/kWh). I used the fob to measure the state of charge. Given the 20 kWh battery pack, the state of charge numbers can also be used to calculate the power consumed and thus the efficiency. I notice that there’s a noticeable discrepancy in the results obtained from the two methods:

Leg 1:
Based on fob SOC: 1.8 Miles/kWh
Based on trip meter: 2.3 miles/kWh

Leg 2:
Based on fob SOC: 1.3 miles/kWh
Based on trip meter: 1.6 miles/kWh

Leg 3:
Based on fob SOC: .43 kWh/mile (net energy gain)
Based on trip meter: 99.9 miles/kWh (probably just the way they indicate net energy gain)

Overall:
Based on fob SOC: 4.6 miles/kWh
Based on trip meter: 5.6 miles/kWh

Anyone know how these differences arise? Apologies if this has already been covered elsewhere in the forum.


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 Post subject: Re: Redlands to Forest Falls
PostPosted: Wed Mar 29, 2017 2:43 pm 
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Joined: Mon Jul 08, 2013 1:28 pm
Posts: 214
Location: Oregon
parker5 wrote:
In the above measurements, I used the trip meters to record the distance and efficiency (miles/kWh). I used the fob to measure the state of charge. Given the 20 kWh battery pack, the state of charge numbers can also be used to calculate the power consumed and thus the efficiency. I notice that there’s a noticeable discrepancy in the results obtained from the two methods:

Leg 1:
Based on fob SOC: 1.8 Miles/kWh
Based on trip meter: 2.3 miles/kWh

Leg 2:
Based on fob SOC: 1.3 miles/kWh
Based on trip meter: 1.6 miles/kWh

Leg 3:
Based on fob SOC: .43 kWh/mile (net energy gain)
Based on trip meter: 99.9 miles/kWh (probably just the way they indicate net energy gain)

Overall:
Based on fob SOC: 4.6 miles/kWh
Based on trip meter: 5.6 miles/kWh

Anyone know how these differences arise? Apologies if this has already been covered elsewhere in the forum.

Useable battery capacity is less than the 20 kWh figure (and varies with temperature). And some have driven (up to 10 miles?) with 0 range remaining, so the SOC% does not reflect entire capacity.

If you use your number to calculate pack capacity, you come in at around 16 to 16.5 kWh. With a small sample size (2 legs) and rounding errors (greater on shorter distances), this number should be taken with a grain of salt. I have tracked my usage (off and on) over the 3+ years to see if there is any noticeable change in range/capacity, but haven't noticed anything significant.

Leg 1:
15.5 miles / 2.3 miles per kWh = 6.7 kWh used
6.7 kWh / 42% of capacity (99%-57%) = 16.0 kWh battery capacity

Leg 2:
4.2 miles / 1.6 miles per kWh = 2.6 kWh used
2.6 kWh / 16% of capacity (57%-41%) = 16.4 kWh battery capacity

Factoring rounding errors (+/- .049) on miles, mpkWh and +/- .49% on SOC %'s gives a range of 15.5 to 16.9 kWh and 15.3 to 18.4

_________________
Gary
----------------------
2014 #262


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 Post subject: Re: Redlands to Forest Falls
PostPosted: Thu Mar 30, 2017 12:39 am 
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Joined: Mon Oct 01, 2012 9:46 pm
Posts: 18
Location: Redlands, CA
Very interesting. Thanks for this analysis!

Ben


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