BMW i3 – Winter Range Reduction & Tips For Offsetting Cold Weather Impact

DEC 11 2014 BY TOM MOLOUGHNEY 17

BMW i3 PSA: No, There is Nothing Wrong With Your Battery!

As the temperatures drop, so will your range. That's life with an electric car, but there are ways to minimize the effects of the cold.

As the temperatures drop, so will your range. That’s life with an electric car, but there are ways to minimize the effects of the cold.

I remember back to my first year in the MINI-E program. It was 2009 and there weren’t many electric vehicles on the roads, especially outside of Southern California. About five months into the MINI-E Trial Lease program there was a rush of participants bringing their cars to their MINI dealer for service, telling them something was wrong with their cars. This occurred in late October…

Suddenly, the cars couldn’t go as far as we were used to, and the range drop off seemed to happen very quickly, without notice and without reason, leaving many people to assume their car was malfunctioning, and perhaps had a bad battery. Some of the people even swore the range drop coincided with their last service visit, so there had to be something done at the dealership that caused the loss of range.

I had read quite a bit about electric cars before getting mine, and knew there would be some range degradation in the cold winter months of Northern New Jersey, but I really didn’t know how much the range would drop. Evidently many of the other participants were completely in the dark about what to expect once the winter months arrived. Some were so put off by the range degradation, they insisted that BMW take the car back and allow them to leave the program. I remember one particular person tell me that drop in range meant they could no longer make the round trip to work every day, so the car was of no use to him for three months of the year.

48 miles was all I could muster before my range extender turned on last week. My battery is fine, it's just cold!

48 miles was all I could muster before my range extender turned on last week. My battery is fine, it’s just cold!

*Editor’s Note: This post appears on Tom’s “The Electric BMW i3” blog.  Check it out here.

When the MINI-E program ended in 2012 I joined the BMW ActiveE lease program. By then some of the participants were aware of the effects the cold weather has on EV batteries since mainstream EVs like the Nissan LEAF and Chevy Volt had both been available for over a year. However there were still quite a few ActiveE drivers who were caught off guard by the loss of range once winter rolled around, and this became a major topic of discussion among the ActiveE discussion forums. Just as with the MINI-E drivers, many believed their car was experiencing some kind of battery problem, and couldn’t believe the range would be affected so much by the cold weather.

So, here we are in 2014 and not much has changed. The i3 launched in May in the US, and the vast majority of owners have never owned an electric vehicle before. Many of those who live in cold weather regions are now finding out firsthand how much the range can be affected by cold weather.

I am the admin in the i3 discussion forum over at mybmwi3.com and the reduction of range has been widely discussed of late. Just as with the MINI-E and ActiveE programs, there are people who are convinced that there is something wrong with their car. I suppose there could be an issue with someone’s car, so I would recommend to anyone concerned to take their car in for service to have it checked out, but I’m sure most everybody is going to get a clean bill of health, and at that point they are going to have to come to grips that the reduced range is due to the temperature, and learn how to live with it.

With temperatures in the low 20's, my predicted range is usually in the low 50's for a fully charged battery.

With temperatures in the low 20’s, my predicted range is usually in the low 50’s for a fully charged battery.

I must say I am a little disappointed in BMW for not offering better educational information for new owners. It wouldn’t have been too difficult or expensive to prepare an information card which helped new owners understand how temperatures can effect their range. I’ve had a couple dozen i3 owners reach out to me already for information about this, many concerned they have a problem with the car. I think BMW should make a “Battery 101” information card and hand it out to all new owners at the time of delivery with their other vehicle documents. This could cover temperature issues as well as tips to help extend the life of their battery, offer advice for long term vehicle storage and offer a brief explanation on how the battery system works. I believe owners would appreciate this kind of information. It feels a little like Groundhog Day with the same questions about range coming up every winter. There has to be a better way to prepare the customers for this before it becomes a problem.

This graphic is supplied to all BMW i certified dealers.  However, few pass this on to i3 buyers.

This graphic is supplied to all BMW i certified dealers. However, few pass this on to i3 buyers.

With temperatures in the 40's, I was averaging 60 to 65 miles of range per charge.

With temperatures in the 40’s, I was averaging 60 to 65 miles of range per charge.

That said, there are techniques to help offset the effects the cold weather has on the battery. Here are some of my recommendations to help you get through the winter:

Precondition: Use the precondition function as much as possible. The i3 will preheat the battery and passenger cabin so you leave with a fully charged and heated battery, plus a warm cabin. By doing so, you will use less of the stored energy in the battery for these functions, which will allow that energy to be used for its main purpose, to propel the vehicle. You can set the preconditioning to begin every day at a set time so your car is ready for you. Make sure the car is plugged in while you precondition because you want to draw energy from the grid to do this, not drain down your battery.

Cabin heat: Limit the use of the cabin heater as much as possible. The BEV i3s are equipped with an advanced heat pump which is much more efficient than the resistance heater used for the REx i3s. However it still can use a fair amount of energy and will indeed cut into the range. If your i3 is equipped with heated seats I highly recommend using them as much as possible. By doing so you can use the cabin heater less which saves energy since the heated seats use less energy than cabin heater; heat pump or not. If you simply dress a little warmer and use the heated seats you can really cut down on the use of the cabin heat, and this will definitely have a positive effect on your range. If you are wondering why i3s with the range extender do not have a heat pump, there are two main reasons. First and most importantly, the actual heat pump on the BEV i3 is located where the gasoline tank is on the i3 REx, so there isn’t room for it. Secondly, squeezing every mile possible out of the battery isn’t quite as important with the REx i3, since you can still continue driving once you exhaust your battery. With the BEV i3, those extra 3 or 4 miles the heat pump may add might make the difference in you getting home or not on a cold night. 

Properly inflated tires: Tire pressure falls as weather turns colder. Some tire experts say that for every 10 degrees of temperature drop your tires can lose 1-2 lbs of pressure. Under-inflated tires create more road friction which will reduce efficiency. Some EV drivers I know actually add  four to five pounds of pressure to all of their tires before the winter months begin. Always make sure to check the recommended and maximum pressure for your tires, as that’s different for every tire and car. 

Park inside: Whenever possible park the car in garages, especially if they are heated. If you park outside for an extended period like while you work, you should find a spot that will be in direct sunlight for as much as possible. By parking in direct sunlight you’ll have a warmer cabin and battery when you return to your car later.

Slow down: Besides preconditioning and conservative use of the cabin heater, driving a little slower is perhaps the best way to extend your range. This is true regardless of the ambient temperature, but during the winter months driving a little slower can help offset the range you lose to the cold. If you do knock off a few miles per hour on the highway, make sure to move over into the right lane so you don’t hold up traffic. Also, try to accelerate slowly form a standstill. Jack-rabbit launches are definitely fun with the i3 but they do consume a lot of energy. 

Charging times increase: While you’re charging, the thermal management system will also be working to warm the batteries. This takes some of the energy that would have gone directly into the battery and uses it for the TMS. On really cold days I’ve noticed it takes my car 30 to 45 minutes longer to fully charge. Knowing this you may have to adjust the delayed charging setting on the car and allow for more time before you can unplug.

Use Eco Pro Modes: The i3 has two Eco driving modes to complement the default “Comfort” driving mode; Eco Pro and Eco Pro+. Both modes reduce power supplied to the motor and energy consuming features like the cabin heater. Most features work fine in Eco Pro mode, but Eco Pro+ restricts the power so much to them that some no longer even function. Another benefit to using Eco Pro and Eco Pro+ in the winter is by reducing the power to the motor the car accelerates slower and helps to reduce the possibility of wheel spin. I definitely recommend using Eco Pro mode whenever driving on ice or snow covered roads.

99 miles of predicted range was the most I have ever seen on my i3. This of course was months ago when the temperatures were in the low 80's. I've never actually been able to drive 99 miles before my range extender turned on though. The most I've ever driven was 90 miles once. I've learned that the Guess-o-Meter can be overly optimistic at times!

99 miles of predicted range was the most I have ever seen on my i3. This of course was months ago when the temperatures were in the low 80’s. I’ve never actually been able to drive 99 miles before my range extender turned on though. The most I’ve ever driven was 90 miles once. I’ve learned that the Guess-o-Meter can be overly optimistic at times!

Below is an interesting chart prepared by FleetCarma. It compares the effects of the cold on the fuel efficiency of an electric car and a gasoline car. It isn’t exactly what I’m discussing here today, but it helps to see how both gas cars as well as electric vehicles are effected by the cold. It’s interesting to see that the cold affects the EV more, but the actually energy cost of the reduced efficiency is less on the EV. So while it may be a greater inconvenience for the electric car driver, the cold weather inefficiencies actually costs the gasoline car driver more money.

FleetCarma Infographic

FleetCarma Infographic

Categories: BMW

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17 Comments on "BMW i3 – Winter Range Reduction & Tips For Offsetting Cold Weather Impact"

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Mo

Thanks Tom. Very helpful. How does it drive on snow?

Tom Moloughney

It’s actually been excellent with the Blizzak snow tires I bought. I’m sure the stock 20″ summer tires wouldn’t be anywhere near as good as these have been.

Brian

Excellent write-up, as usual. Thanks for sharing, Tom!

These are all good tips from a seasoned pro. I really don’t have much to add for increasing winter range in an EV. I might point out that cold air is denser than warm air, which is why slowing down will help even more in the winter than the summer.

I like your suggestion of an information card to hand out to customers. I might even recommend that the dealer discuss this with customers BEFORE the purchase. I would hate to buy a car only to find out immediately after signing that it cannot cover my commute in the winter. That sort of thing builds ill-will towards EVs in general.

David

A nice write-up that would be greatly improved with some proofreading. In particular there are many instances of the word “effect” where the word “affect” should be used.

Tom Moloughney

Guilty as charged. Honestly I can just never get those right 🙁

David

Regarding seasonal range I like to say that I drive an EV in the Spring, Summer, and Fall. I drive a Hybrid in the Winter.

I drive a Volt.

Stephen

Its better than a hybrid. My commute is 36 miles. For 6 months of the year I easily do it as EV only (max seen 46m). In Oct it flipped to where I am lucky if I get home before the gas engine starts. This month seems to be low 30 miles. Gas use rarely exceeds 0.1 gal per day.

GR33N

Good tips, for all EV drivers too

As usual, good work Tom.

I love the fleetcarma graphic. Thanks for passing it along. I have described this idea to people without the numbers to back it up.

pjwood

RE: $.15, to .172 cents per mile, in cold.

I never experienced a 14% loss, in an ICE car, on the way down to 32F. 3-5% maaaaaybe. I think because hybrids get put into the ICE mix, those numbers somehow get a lot worse. Just seems that, since the dawn of my driving time (decades), I’d always lose 2-3mpg when it got “colder”.

I read (on the internet) today that OPEC may keep the taps open for no less than 6 more months. At that rate, a 30mpg ICE’r could fall considerably below $.10, not $.15, per mile. Not forever, but ‘Monthly Sales’ could get rough.

Jsmay311

So in your decades of driving experience, you’d you lose “3-5%” efficiency, or “2-3 mpg” in cold temps?

So… Just doing a little math, that means that your typical warm weather efficiency over the decades has been somewhere in the range of 40-100mpg???

Bill Howland
First off, Tom, thanks for the article. Seems pretty accurate actually.. Just one or two things: 1). I agree with the others that at 32 degrees, you can’t really say you lose too much gasoline range once the engine warms up. I notice an odd quirk of the Chevy Volt’s engine, that when it is even somewhat cold the thing sucks gas. After a good warm up (And i mean GOOD), the thing barely sips gas. But most gas cars don’t have this large a range penalty. After all, during the winter time in Buffalo, 32 degrees fahrenheit is truly HOT since we rarely see it. 2). Buffalo is just east of one of the great lakes, therefore our relative humidity is out of this world in the Cold Winter Months. CONSTANT defroster use is mandatory, otherwise you’ll crash because you can’t see where you are going. Perhaps this is unfortunately one of the few towns where seat heaters can’t help you much. During MODERATE (spring and fall weather), which would be BONECHILLINGCOLD for anyone in California, the seat heaters in both my cars do save electricity, and, during the spring and fall, one can get by with them.
ModernMarvelFan

@ Tom,

Those are great tips and it applies to just about all plugin car owners..

One thing I am still puzzled is that why doesn’t BMW allow the REx heat to be used in the cabin? I know it adds slight complexity and cost, but the winter benefit is so big that I can’t see why they should be wasted…

Since I live in a relatively mild California, 45 degree is cold enough for me to demand some heat. Heated seat is good but it only keeps half of my body warm.

In my experience, the defogger is the biggest drain on my range since the car turns on heater and A/C at the same time to dry up the air.

Tom Moloughney

I believe the main reason is you really don’t use the REx much at all. Other than the occasional very long drive, you won’t be using the REx much, and when you do, it’s probably for the last 5-20 miles of your day and by then the car is warmed up anyway. Besides, once it’s turned on, it provides enough energy to run the cabin heater and power the car (except for the long sustained mountain climbs that we have discussed a lot) so I’m just not sure it’s needed. With my personal driving for instance, I would have only been able to use the waste heat three times so far in the past two months of cold weather. The other times my REx turned on it was for the final 3-6 miles of my trip and the engine wouldn’t have even been warmed up enough to provide heat in that short of a time.

If the i3 had a shorter electric range than I agree it would be a great feature, but with the electric range what it is I just don’t think it would be worth the trouble.

Djoni

In fact any ICE engine could provide instant heat with the exhaust heat has it’s done on the las Prius or as in any small private airplane.
Probably some other device too.
It’s à lot cheper too than using the cooling fluid of the engine.
Just saying!

Ajay

An interesting difference between my Ford Focus Electric, which I just returned after the lease ended, and my new i3 BEV is that the FFE only allowed preconditioning when the car was plugged in, while the i3 allows preconditioning even when its not plugged in. I typically precondition before I drive in the cold even when not plugged in. Then when I start driving keep the heat off and only, if needed, turn on the seat warmer. I was wondering if the net value of preconditioning on both the cabin temperature and battery performance exceeds the cost of having turned on preconditioning when the car was not plugged in. My subjective feeling is that preconditioning even when not plugged in provides some benefit but I have not systematically collected any quantitative data to support this conclusion. Does anyone else know? Does BMW suggest preconditioning even when not plugged in?

theo mondle

Very helpful read being an i3 BEV owner. Hit 36 degrees in Los Angeles last night. Thanks Tom for the write up. Have a great New Year.