How does using the heater effect travel distance

Discussion in 'Clarity' started by bpratt, Dec 26, 2018.

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  1. bpratt

    bpratt Active Member

    Using this chart thanks to insightman:
    Clarity miles vs speed.png
    It shows the Clarity range is about 47 miles at average speed 15mph, 55 miles at 30mph and 48 miles at 45mph. I measured the Clarity heater uses about .2 miles per minute when the outside temperature is 25 degrees. So based on those figures, I produced the following chart:

    Speed miles/min heater total m/min 0 miles after actual traveled if heat=.1

    Miles/m Miles

    15 mph .25 .2 .45 104.4 min 26.1 33.6

    30 mph .5 .2 .7 78.6 min 39.3 45.8

    45 mph .75 .2 .95 50.5 min 37.9 42.4

    The last field shows that for warmer temperatures where the heater is using .1 miles per minute, the actual traveled miles would be much higher.

    Sorry, I can't seem to get columns to align properly. The columns should read:
    Speed, miles/minute, heater Miles/minute, total miles/minute, 0 miles after miles, actual traveled miles if heater used .1 miles/minute.
     
    Last edited: Dec 26, 2018
    BobS likes this.
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  3. Sandroad

    Sandroad Well-Known Member

    What was the inside temperature set on when you measured the 0.2 miles per minute usage by the heater?

    Very interesting. That would mean a loss of 2 miles in a 10 minute trip (assuming full pre-conditioning) and a loss of 20 miles in a 100 minute trip (which couldn’t be EV anyway). That seems minimal!

    In your columns, it looks like heater use increased miles driven, so I don’t understand that data.
     
  4. aldaris1234

    aldaris1234 New Member

    Those numbers seem reasonable. When it was in the low 30s to high 20s outside and the heater was turned to 62 it seemed like my 2 mile (10 minute) commute would drain off 4 miles instead of the usual 2.
     
  5. bpratt

    bpratt Active Member

    The temperature was set at 70. I sat with the car turned on but not moving for about 20 minutes with a stopwatch. When the EV mile would drop, I would make note of the time. On average, I would loose 1/10 mile every 32 seconds. The outside temperature was about 26 F degrees.
    I don't see where you think the heater use increased mileage. At 30 mph for example without heater use, I show the car should get 55 miles of EV with a full charge. With the heater using .2 miles per minute, you could only travel 39.3 miles, if the heater is using .1 miles per minute, you could travel 45.8 miles. Both of those numbers are a reduction of the 55 miles of EV with no heater use.
     
  6. Sandroad

    Sandroad Well-Known Member

    I guess I didn't read the columns correctly. Thanks for posting this. Heater use effects on the battery is good Clarity data info.
     
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  8. Viking79

    Viking79 Well-Known Member

    As a general rule, these resistance type heaters (either PTC or nichrome) are around 5 to 8 kW on cars. The i3 has a 5.5 kW unit and the Bolt EV has a 7.5 kW unit.

    Someone might have posted a tech document here on the Clarity PHEV, but I can't find it now. Anyway, I will pick 6 kW since the battery is about 12 kWh usable. It is easy to see that at full power it would drain the battery in 2 hours in that situation. If your cold weather range is 35 miles and you drain the battery in 120 minutes that would be .3 miles per minute.

    The documents I can't find right now show that it can run at several levels using different points on the coil. Bottom line is the heater can be a huge drain on the battery.
     
  9. MNSteve

    MNSteve Well-Known Member

    Looks like the seat heaters are not a significant user of power. The fuse is 20 A, so that's a max of 240 watts with both of them on full bore. A tiny fraction of the amount used by the heat.
     
  10. Atkinson

    Atkinson Active Member

    Yup,you are better off heating yourself directly with seat heaters than heating fresh air that will leave the cabin through exhaust vents.
    Course that doesn't address defogging............
     

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