First Winter Drive

[oilerlord]

Did a quick experiment. Today it was 3F. Wind blowing at 12 mph. Took two 43.5 mile round trips to the same destination and back. Both trips started from my heated garage at 57F, and the car parked for 5 minutes in the cold at the destination.

Trip one had driver's seat heater, and climate control set to 72F. Trip two had driver's seat heater on, and sparing use of climate control (approx on 1 minute / off 10 minutes) just to defog windows. Trip was 95% highway, cruise set to 59 mph.

Results:

Trip 1 - 20.44 kWh used. 2.13 miles/kWh
Trip 2 - 15.68 kWh used. 2.77 miles/kWh

Wow. With heater running, this indicates a total 28kWh battery range of 59.64 miles being comfortable, or 77.56 miles if I choose frostbite. I knew the heater was a big power draw, but didn't know it was that severe. At least I now have a baseline of what to expect.

 

[Dracula]

It is also likely that the battery was already warm / conditioned after the first trip, hence the battery heater used less energy on the second trip. To account for this factor, it would help to repeat the experiment in reverse order - first drive with the cabin heater off, then with the heater on.

 

[oilerlord]

The battery just finished charging before the second trip, so it's true that the battery would have been warmer than the ambient (57F) garage temperature on the first trip. I have no way of knowing what the starting temperature of the battery was on the second trip, though I'd assume that it's thermal management would attempt to keep it around 72F while charging and discharging. Would that be enough to account for a 30% hit in range? At 3F, and based on how quickly the inside of the cabin cooled off, the battery heater would have kicked in within a couple of minutes of leaving my heated garage.

I'll pre-condition the battery on both trips the next time around to eliminate that variable. I'll also put on my cold weather survival gear so I can avoid turning off the cabin heater as much as possible too.

 

[JeffRay]

oilerlord,

Nice post and good directional data to confirm our prior observations. Yes, the guidance is to prewarm the cabin and battery while plugged in at garage prior to run out on cold days. Limit use of cabin heater and to wear coat in car. All to maximize range.

For me, mine is worse as I only average 12 mph in stop and go urban driving and I park outdoors at home with no way to prewarm car and battery while plugged in. To my recollection, my range was as low as 30 miles when I used the cabin heater and warmed up the car before the kids jumped into car. This winter, at least I can plug in outside at work and top off my battery at 1.0kwh. I will have to fully recharge my car during the week overnight at a commercial charging station.

 

[oilerlord]

Clearly, there will be days when I'll need more than 60 miles from a full charge, so I'm going to pick up one of these (along with a CO detector):

http://www.canadiantire.ca/en/pdp/mr-heater-little-buddy-heater-0762356p.html#srp

I'm going to mount the heater on a piece of MDF, and secure the MDF to the cargo floor. I'll have to either crack a window or run the vent fan on low for safety, and to balance the 3800 BTU's this thing puts out. Today it's -4F. The heater will come in very handy when we eventually see -20F.

 

[JeffRay]

oilerlord,

I will have to look into it. Why be cold? I actually put an electric blanket over the rear seat for my kids plugged into a rechargeable portable battery for cars (air pump, jump start, outlets).

Since I have the portable battery, I just went to Amazon.com and bought a small electric portable heater for $15 to plug into it. Better to suck down the portable battery than the main car battery.
Perhaps safer than gas heater in car.

 

[Dracula]

Clearly, there will be days when I'll need more than 60 miles from a full charge, so I'm going to pick up one of these (along with a CO detector):

http://www.canadiantire.ca/en/pdp/mr-heater-little-buddy-heater-0762356p.html#srp

I'm going to mount the heater on a piece of MDF, and secure the MDF to the cargo floor. I'll have to either crack a window or run the vent fan on low for safety, and to balance the 3800 BTU's this thing puts out. Today it's -4F. The heater will come in very handy when we eventually see -20F.

This is a radiant heater, and putting it in the trunk will limit its efficiency as it will not have direct line of sight to driver and passengers. There are also huge risks - fire, CO poisoning, difficult to control while driving etc. Really, if it is too cold for an electric car, maybe the Volt is what you truly need.

 

[JeffRay]

Now now, lets be nice on this forum. Oilerlord did a lot of research before settling on the MBe and he seems to be on the front end of learning how to maximize its use. There are lots of good posts on ideas to extend range in cold weather and his addition of a portable heater is something I am adopting for mine. Not a propane heater but an electric heater to use with the portable battery I got to power an electric blanket. It will be interesting to see how long it takes for the electric heater to suck down the limited wattage in the battery. Hopefully, long enough to warm up the car 10 degrees. Test results will be posted!

 

[oilerlord]

"There are also huge risks - fire, CO poisoning, difficult to control while driving etc. Really, if it is too cold for an electric car, maybe the Volt is what you truly need."

I wouldn't describe the risks as "huge". We don't have any kids, and 95% of the time, I'm the only one in the car. As I mentioned, I'd do my best to mitigate risk by securely mounting it, vent the cabin while in operation, and use a CO detector. This line of heaters have low oxygen and tip angle shutoff. These are indoor rated heaters, but I do realize that they weren't intended for use inside a car. The bigger problem I've been reading is that propane heaters emit a moist heat, adding humidity - so for that reason it may not work at all for my purposes. The only way to know for sure is to try it.

The cold snap we're having doesn't last months at a time, and I knew going in that there would be challenges with driving a 100 mile EV in winter. Thank you for your suggestion but I'd rather ride the bus than buy a Volt. I can always trade off cars with my wife since her commute is only a 20 mile return trip.

I made another post about the possibility of installing an Espar hydronic diesel heater. The heater warms the coolant, which would have the additional benefit of warming the main battery. I'd have to find a service manual for the car to see if one can be installed, and what other risks could arise (like cooking the battery). These heaters are amazing, and burn very little fuel. All told, it's probably a $1200 solution vs the reality of accepting 50-60 miles of range in extreme cold. For that reason, a $90 heater + mount + CO detector may be all I need but long term, the Espar heater is likely the far better way to go.

I just remembered that I have a Bluetooth OBD2 transmitter. I'll bet that my android Torque app would give me all sorts of data, including battery temperature. Perhaps the Espar coolant heater is the way to go, but I'm not sure if the coolant reservoir is designed only for heating the battery - or if it's also used to heat the cabin.

Here's a cool set of videos that my friend Ben posted for the process of installing an Espar heater in his iMiEV:

https://www.youtube.com/watch?v=3RHiDYGPZlY

 

[oilerlord]

I ended up buying a slightly larger heater:

https://www.homedepot.ca/en/home/p.1000757433.html?eid=PS_GOOGLE_HD+%7C+PLAs_Shopping+%7C+Appliances+-+Small_Small+Appliances&gclid=CKCN6PWb5dACFQaUaQodfiALaA

The heater is well made, simple to set up, and easy to light. I ended up putting it in the middle back seat, and secured it by intertwining the rear R+L seat belts around the handle and back of the unit. It was the perfect location for it, pretty much the center of the car and still accessible to turn off/on from the driver's seat.

As it was -7F this morning, today was the perfect day to test it. Unfortunately, it gave mixed results. While the unit clearly kicks out more than enough heat even on the low 4000 BTU setting, the windows fog up. That necessitates running the defrost, and since the goal is trying to avoid runnning the car's heater, but still have a fresh supply of oxygen for me, that means ice-cold vent air blowing into the cabin. It's a constant battle trying to balance the cabin temperature and defog windows. Pretty sure I'm going to return it.

Looks like the diesel heater is the way to go.

EDIT: May have found a compromise. I set the heat to 60F, which is one notch above "low". Turned on AC, and have the fan blowing about medium speed. No doubt this still drains the battery but I'm hoping that the car's resistive heater isn't just an on/off function, but has various steps of power consumption depending if it's set at 80F, 70F, or 60F. The air coming out of the vents is cool, but not the ice cold variety that the "low" setting provides. Again, does the car's climate control give low heat - or does it simply mix hot air with outside air to produce the desired setting. No way to know for sure without talking with an engineer, or taking the car out for another drive and testing it. Unfortunately my android Torque app doesn't have the OBD2 protocol to communicate with the car. If it did, I'm sure I could easily find out EXACTLY what the power consumption is at any given moment.

The easiest option would be to use the the "auto" climate control setting, but the propane heater warms the interior to the point that the fan shuts off - which is a no-go because of CO concerns, and also because the windows fog quickly when the fan isn't running.

I'm going to visit a client tomorrow that will put ~40 mostly-highway miles on the car. I'll set the car to 60F, A/C on, and fan on medium. We'll see if that helps range compared with my first posted test. It will be another cold day tomorrow.

 

[Dracula]

According to your plan, the temperature inside your car needs to stabilize at 60 deg F, with the heat losses to the exterior being made up partly by the propane heater, and partly by the resistive heater. Why not stabilize the car temperature at 70 deg F, so you can be comfortable?

Regarde fogging of the windows, unless the glass gets warm, or the humidity inside the car is low, you may not be able to prevent it. You may want to try to crack open one of the rear windows, so the humidity, and hopefully the CO, can escape.

 

[oilerlord]

Well, I have my answer. It doesn't matter if the temperature is set at 60F or 72 - running the cabin heater takes the same amount of energy.

Today it was -3F outside. I ran the propane heater, cabin temperature set at 60F with fan running at 50% to keep windows from fogging:

52.18 miles (95% highway), 23.18 kWh consumed - 2.19 miles per kWh. Essentially same efficiency as my first trip (2.13 miles per kWh) using the car's own heater set at 72F - and being comfortable without windows fogging and no risk of CO poisoning. I'm going to return the propane heater. At the very least, I hope this test has helped anyone that considered trying this. Really, it isn't worth the trouble.

Clearly the main traction battery heater and/or temperature of the battery itself has a lot more to do with the car's range than running the car's heater does. To that point, the car's cabin heater is very good, even in extreme cold temperatures.

I'm going to go the diesel heater route. If I can keep the battery warm, I'll be able to run the cabin heater without too much of a range penalty. I'm guessing that once installed, I may be able to get efficiency back to ~3.5 miles per kWh while running the heater.

To be continued.

 

[JeffRay]

First try with portable auto battery and small electric heater did not work. Took everything home to charge up and test on dining table. I have a feeling that the small electric heater sucks too many AMPs vs what the battery can provide. Or maybe it needed a full charge.

 

[JeffRay]

OK, we had our first cold snap in NY with temperatures in the teens. Given the time of year, i.e. yearenditis, I drove my wife's wagon the last couple of days as I wanted to preserve the remaining battery for the 22 mile roundtrip Saturday to my mechanic. Then off to plug in over the weekend to get back to 100% for next week. I could have plugged into a commercial charger but that would have cost money and been a hassle. Such is life with a limited range electric and no home garage to plug in and only a 110 outlet at work. I think I am gonna press the landlord to upgrade the outlet to a 220 since they charge me $25 per month for the privilege of using it.

Happy holidays all.

 

[oilerlord]

It's interesting coming back to this a year later.

It was -19F on Friday. Starting from my heated garage, and a full charge, I did a round trip to see a client yesterday. 22 miles each way / 44 miles total. Pulling into my garage, the car indicated 20% charge remaining. I had the seat heater on the entire time, but was making conservative use of the heater; had it set at 72F but had it on ~ 50% of the time, mostly to keep the windows clear. It was a freeway drive at between 55-60 mph. Based on those conditions, I'm pegging total range at about 53 miles. As a comparison, at anything above 60F, I can break 100 miles without much effort. These truly are California cars.

Had to see the same client again yesterday, but this time I took my wife's X3. It felt so luxurious being warm on the drive. Her car has a steering wheel heater too, that would be a nice touch in our B's. Fortunately, this cold snap is breaking this week with temperatures getting up into the mid 30's.

 

[GlennD]

Boy it sure has been cold here. When I got up the temperature was 45 degrees F.

 

[JeffRay]

With overnight temperatures in the 30s and my B250e parked outside, range has predictably dropped to 50ish miles. Even with my short daily commute to work, it still means charging 2-3 times a week lately when the gauge has dropped below 50%. Sort of a hassle so I have been using our gas wagon when inconvenient to head to a charging station (free or not free). Had to gas up today and for yucks looked at the wagon's GOM which read 425 miles, then quickly dropped to 250 miles once I started driving in urban traffic where it gets 12 miles per gallon.

I guess I rationalize by saying the gas vehicles need to be run every once in a while to stay in shape. But really, my tolerance for heading to a charging station is once a week. Fine in warm weather but not in the winter. Plus the torque on the B250e can cause wheels to spin off the mark when there is stuff on the ground.