First real cold of the season in MD

[MrDRMorgan]

Results are in! Early this morning I re-ran my test for 60 minutes and took readings every 3 minutes for a total of 20 readings. Outside temperature, according to the car, remained at 48 deg. F for the duration of the test. The car was fully charged last night and rolled out onto the driveway. This morning the guess-o-meter read 107 miles.
Summary:
1. The power consumption was quite linear - averaged .125 kWh every 3 minutes. A total of 2.5 kWh was consumed during the 60 minute test.
2. The guess-o-meter dropped from 107 to 93 miles or, in other terms, the range dropped .233 miles per minute of heater use. Battery capacity consumed by the heater was 14% at the end of the test.
4. I took cabin temperature readings starting at the 15 minute mark. At the 15 minute point the cabin temperature was 68.7 deg. F. At the 60 minute point the cabin temperature was 82 deg. F even though I had the temperature set to 75 deg. F. The set point may only work in the AUTO mode. I need to do more testing to find out.
5. There may be other non-heater related power consuming functions going too. The only way to find out is repeat the test by powering up the car and leave the heater turned off.

My next test will be on Tuesday when the morning low is forecasted to be 36 deg. F. I plan to take a 40 mile round trip drive using the same heater settings and determine what the total vehicle mileage performance hit will be under cold weather conditions normally occurring in my area during the winter months. My reference value will be 5.6 mi / kWh [includes some AC use]. This was my average last month for 734 miles.

 

[dangerHV]

Excellent test. I'm going to print this thread for future reference. Thanks Doc.

David

 

[MrDRMorgan]

I tried a different test today. Early This morning I drove 4 miles to church and returned at 12:30 pm following the same route. The heater was set to 77 deg. F , the fan speed set to 3 bars, the inside / outside air was set to inside air and the AUTO climate control was off. Vehicle speed ranged between 40-45 mph, I consumed 2.3 kWh and the odometer indicated I drove 8 miles. 8 miles / 2.3 kWh = 3.48 mi / kWh!

I repeated the same test this afternoon but with 2 people in the car. This time I consumed 2.5 kWh. The odometer showed I drove 9 miles. So 9 miles / 2.5 kWh = 3.6 mi / kWh.

If I average both trips I get 17 miles / 4.8 kWh = 3.54 mi / kWh!!!

I repeated the test again [one person in the car] but this time I turned the heater off. Results this time: I had 8 miles / 1.5 kWh = 5.33 mi / kWh.

It looks like the heater is a real "RANGE KILLER" and I can expect to get about 66% of what I would get with the heater turned off. Said another way and using 18 kWh as the battery capacity, I can go 96 miles with the heater off and only 64 miles with the heater turned on to the settings I used. This might be even worse in much colder weather.

I will fully charge my car Monday night and early Tuesday morning I will repeat my 40 mile test if the temperature is in the 30s and it isn't raining. If my assumptions are correct, I expect I will only have about 24 miles remaining at the end of the test.

Use of the heater should also really screw up the guess-o-meter range estimate. I still need to evaluate climate power consumption in the AUTO mode using the same 77 deg. F set point. A quick check indicated it might actually use a bit less power than the non-AUTO mode.

9 Nov 2015:
I couldn't wait to try the AUTO climate setting so this morning I set out on the 40 mile round trip drive to test it out. The outside air temp was 49 deg. F when I started and was 52 deg. F when I ended. Sure enough, miles per kWh dropped to 3.3 - 3.5 at the start but as the cabin heated up - I set the temp to 75 deg. F - the miles / kWh improved and I got 4.3 mi / kWh for the 40 mile trip.

The AUTO setting for the climate control is the way to go. However, for short trips of about 10 miles or less, or possibly longer in very cold weather, you can expect to start at about 3.0 - 3.5 mi / kWh (assuming normal driving) and, as the cabin warms up, miles / kWh will gradually improve. Lower outside temperatures will stretch out the time it takes for the heater power to start dropping off.

The guess-o-meter really takes a hit as the computer tries to estimate range based on fluctuating heater power consumption. After all of my previous testing, my full charge last night topped off at 94 miles - down from 107 miles. I drove a total of 51 miles today but the GOM showed 67 miles. Further, when I recharged the car, I could only get 86 miles for a full charge. I expected that and it will probably get much lower depending on how much heater power I draw and how cold it is outside. I estimate the lower limit for me could be as low as 63 miles if I use the heater heavily and drive only short-mileage trips. I find I am now keeping a closer eye on the energy used number found in ENERGY DETAILS on the display [hit the LEAF button to get there]. You can also use the TRIP METER but be sure to reset it before you start driving each day so you get accurate data for that day / trip.

Tomorrow morning the outside temperature should be in the mid to high 30s. A few short trips will be in order.

10 Nov 2015:
This morning it was 48 deg. F outside and the car had been out all night. I turned on the AUTO climate control, set the cabin temperature to 74 deg. F and drove off for a short 4 mile trip and back. The car averaged 3.07 mi / kWh going - lowest reading was 2.8 mi / kWh - and 4.0 mi/kWh returning. The guess-o-meter fell like a rock. Then I did errands around town with many stops included. At the end I had traveled 27 miles and used 7.1 kWh from the battery for an average of 3.80 mi / kWh. The guess-o-meter dropped from 88 miles at the start to 47 miles at the end.

The vehicle's heater is a real range killer. If this is a problem for you, try preheating the cabin before driving by using an L2 charger. Then use the heated seats instead. I like a warm cabin and these tests show me I only need be concerned if my out and back distance is further than the reduced range caused by the heater and I can't find a DCFC along the way.

- End of Test -