Practical solutions for extending cold weather range

[Don]

The defrost setting on the car's climate control uses either the A/C or the same heating element that you use to heat the car. The rear window defroster uses a very negligible amount of juice

Remember, the RR number you get after a full recharge is mostly affected by what happened in the last 15 miles of driving immediately before you recharged - If you were using the climate controls during those 15 miles, your new RR number will be lower than it would be if you were using no climate control

Don

 

[blackheart]

We just experienced a 20+ degree bump (Fahrenheit) in temp the last couple of days, and my range/efficiency has gone through the roof. It's like my car is brand new again (I purchased it during an early warm spring, so this is my first winter with my Miev).
I know that this information is out there, but I am having a hard time finding it. What is the draw of my seat heater?
According to Canion, I am easily using about 600-1200kw less on my drive. The only thing I am not using is my seat heater. I didn't think that it drew that much. Its only a 25 min drive. Can someone point me in the right direction? I didn't think moving from the 40's to the 60's would increase the efficiency of my car.
(Might not be the correct thread - administrators move at will - thanks!!)

 

[PV1]

The manual should list the fuse size for the heated seat. If I remember correctly, the heated seat uses about 120 watts when on, but it cycles. Put simply, the headlights use more.

I would think this is still on-topic. Heated seats are about the best thing going for helping winter range (for me, it all but eliminates the need for cabin heat when combined with remote pre-heating).

 

[blackheart]

The manual should list the fuse size for the heated seat. If I remember correctly, the heated seat uses about 120 watts when on, but it cycles. Put simply, the headlights use more.

I would think this is still on-topic. Heated seats are about the best thing going for helping winter range (for me, it all but eliminates the need for cabin heat when combined with remote pre-heating).

I wouldn't think that it would make up for the drastic change in consumption of the car during my commute at 120 watts. My total commute, in warm weather, normally consumes about 7-8 bars (round trip). Most of the winter it was consuming 13, likely due to heater use. But with no heater use, I was still using 10 bars. That would be 2-3 kilowatts - for a total drive time of 45-60 min. That seems like a huge jump.
I thought that the car's efficiency wouldn't change much in milder temps (40°F+).

I still need to figure out how to utilize my e-bike battery for auxiliary heat - just for fun and experimenting. But I am amazed at how little power my little car uses in the warmer weather....

 

[PV1]

Colder air causes increased bearing drag, a slight drop in tire pressure, and denser air. This all adds up, and really contributes to losing range when it drops below 10 F outside.

This is why I don't see much range drop from A/C, as the drop in motive power draw makes up for A/C usage when the temperature gets high enough for me to run it.

 

[jray3]

Taking a cue from the hypermiling hipsters at Ecomodder.com, and of all places, Chrysler Corp, which is introducing a coolant-heated rear axle on their next pickup, I intend to try a transmission heater this winter.
http://fcauthority.com/2018/01/2019...er-thermal-management-tech-feature-spotlight/
The impact may be difficult to quantify, ecpecially because our cars use ATF, which isn't nearly as thick and sticky as the 80W gear lube in my VW conversion, but if I'm reading this chart of viscosity correctly, ATF is 9 times more resistant to flow at freezing temperature than at 50 C/ 122 F!

If I'm really diligent, I'll jack the car up in freezing temps, press the accelerator and measure the amps vs wheelspeed, then do the same after heating the oil... :mrgreen:

 

[Don]

Remember, the RR number you get after a full recharge is mostly affected by what happened in the last 15 miles of driving immediately before you recharged - If you were using the climate controls during those 15 miles, your new RR number will be lower than it would be if you were using no climate control

Actually, I'm pretty sure I'm wrong here - The computer seems to keep track of the HVAC energy separately. With our current 90+ days, I'm driving with the A/C on all the time and still get RR's of 75 to 80 after a recharge (if I shut off the A/C to check the number) and then when I turn on the A/C after a full recharge, I lose about 10 miles of RR immediately when I switch it on. No way I would be seeing 80 miles RR after a recharge if the A/C energy was part of the computation

Don

 

[Don]

If I'm really diligent, I'll jack the car up in freezing temps, press the accelerator and measure the amps vs wheelspeed, then do the same after heating the oil... :mrgreen:

Will it show wheelspeed . . . . or does the speedo run off a front wheel? With my old Corvairs, (VW's too?) the speedo was driven off the drivers side front wheel. On the iMiEV's with the ABS sensors on every wheel, they could be using any one they chose

I think you'll need a much more sensitive ammeter than the one on the dash - With the wheels off the ground and no load on the drive trail, the difference between your hot and cold readings may be just a few amps and the ammeter in the dash is zero to about 150 amps full scale - Hard to see the difference between 3 or 4 amps on that one

Don

 

[kiev]

i think Jay might have an i909 MUT clone, so he can read motor current over the OBDII CAN buss.

i wouldn't press accelerator, just measure the current in gear when it goes into creep mode. The higher viscosity will cause the creep torque to be higher. In this way you take out some variables such as heating during acceleration, variations in the set speed, how long held at speed, etc. Or at least make the creep mode test first, then try the accel run; then heat up the Jenner and repeat the sequence.

 

[jray3]

i think Jay might have an i909 MUT clone, so he can read motor current over the OBDII CAN buss.
i wouldn't press accelerator, just measure the current in gear when it goes into creep mode.

Good points, Don and Kiev. Yes, I have the i909, and creep mode oughtta show the greatest difference, unless it just delivers an amperage setpoint, then the difference would be in wheelspeed, not amps. I suspect it is amps, as we don't 'creep' uphill. EVen in that case, it should be doable to manually count rpm, via video if need be.

If memory serves, our speedo is on the rear wheels. I blipped the pedal with the car on a lift while doing the lowering job a few years ago and took a video of the incredible 'acceleration'.

 

[belcat]

A few of us developed a Cold Weather Chart last winter. The i-MiEV will not charge or start below -30c/-22F. The Battery Warmer only operates between -15c/-30c.

http://myimiev.com/forum/viewtopic.php?f=28&t=713

I'm not sure where this "chart" comes from, but it contradicts tests done in Canada, in Winnipeg, often cited as the "coldest city in Canada" (not true if you could the northern section).

https://www.rrc.ca/vtec/files/2019/05/iMiEV-Report-3rd-year.pdf

An additional minor winter
vulnerability appeared with the Blue
iMiEV when ambient temperatures
became very cold, i.e., around -30°C
or lower. The screen display on the
vehicle’s navigation system — part
of the premium package on the car
— would not function, as illustrated
in the photograph at right. This was
only a temporary situation, which
was always rectified once the vehicle
had been operated for five or so
minutes. Also no important control
was lost.
One surprising winter advantage for
the iMiEV and other electric vehicles
emerged during an extremely cold
period, i.e., at ambient temperature
around -35°C. Such cold weather
is well known to be detrimental for
the 12-volt batteries of conventional
vehicles, causing very high numbers
of start-failures that require battery
boosting of some kind. And yet,
under the same conditions, a series
of electric vehicles, including the
iMiEVs, were found to be highly
robust in terms of being able to
start up and quickly drive away. In
an interesting paradox, on the day
in question, the driver of the Blue
iMiEV reported literally passing two
disabled conventional vehicles, both
with the front-hood characteristically
open; one being boosted, the
second waiting for a boost. This is a
significant advantage.