BMW i3: Understanding How Preconditioning Works

Setting the preconditioning feature from the i3's iDrive is simple, but not as intuitive as I believe it could be. You can set the time of departure for every day of the week and the i3 will be charged, preconditioned and ready, provided you're charging from a proper 240v, level 2 electric supply. 

In many ways electric cars are very similar to their internal combustion counterparts and that's by design. Most major OEMs are afraid to make something that's "too different" from what their existing customer base is comfortable with. However there are features in electric vehicles that are indeed drastically different. The first one that comes to mind is regenerative braking which allows the electric motor to convert the vehicle's kinetic energy back into electricity which in turn recharges the battery. This feature changes the driving dynamics of the car (some more than others depending on how aggressive the regenerative braking system is) and the operator needs to adjust to this when they first transition to an electric vehicle.

During the winter months preconditioning in New Jersey not only means getting into a warm car in the morning, but it also adds valuable miles to the car's range by warming the battery cells up to their preferred operating temperature.

Another unique feature most modern electric vehicles have is the ability to precondition (warm or cool) the high voltage traction battery as well as the passenger cabin. This allows the driver to begin their journey with a properly heated or cooled battery and cabin, while still having the state of charge at or near 100%. Some conventional combustion cars also allow you to remotely start the vehicle to warm it up in the winter or cool it off in the summer, but the reasoning behind that is purely comfort-driven, and with EVs it goes beyond that. Since electric vehicles have shorter range and longer refueling times than their combustion counterparts, it's important to save the energy in the battery for its main purpose; to propel the vehicle, and not waste too much of it on ancillary power draws.

Warming the battery and the cabin uses a lot of energy, and doing so while the vehicle is plugged into the main power allows the driver to begin their trip with a properly warmed battery (which will increase the range) and still have a fully charged pack. This is very important for EV owners in cold weather climates. It is also useful to cool the car in hot ambient temperatures, but more frequently used by EV owners in the cold since a cold battery can reduce its range up to 30%. A hot battery won't reduce the car's range, but it can have an adverse effect on the longevity of the battery cells. Therefore preconditioning the battery in very hot climates is also advised, but for different reasons than doing so in the cold.

During the day my i3 is parked outside while I work. Accessing the preconditioning from my iRemote app is very useful as I don't have to go outside to the car to turn it on.

OK, so it's clear preconditioning is useful, but do you really know how it works on your i3? I'm afraid most i3 owners don't. In fact, judging by how many people have messaged me this winter asking for help with preconditioning, I'm thinking it's right up there with how to properly care for their battery as the top misunderstood items of i3 ownership. This is all new stuff, and even most dealers don't know all of the answers so it's no surprise the customers are a bit confused. This post should clear the air on most questions about how preconditioning works on your i3. I knew how most of the i3's preconditioning worked, but just to make sure I didn't have anything confused, I reached out to BMW's top electric vehicle technical services manager in the US to get answers to direct questions that I had previously received from readers:

Q. When Preconditioning via the iRemote app Remote Control menu is activated, only the cabin is preconditioned, not the battery, correct?

A. When triggering Preconditioning from the Remote Control menu, the answer is Yes, only the cabin.

Q. If you want to precondition the battery from the app, you need to set the departure time and then enable �preconditioning for departure," correct? 

A. Yes, provided the departure time programmed is at least 3 hours from the time when it is selected.
*Important: This is a very important fact that most i3 owners are not aware of. If you don't set the departure time at least three hours in advance the car is not performing battery preconditioning at all, only the cabin will be preconditioned.

Q. Can you precondition the battery without the vehicle being plugged in?
A. The HV battery, no. The cabin, yes.

Q. Can you precondition the battery while the vehicle is plugged into a 120v source or does it need to be connected to a 240v source?
A. 120V (Level 1/OUC) or 240V (Level 2) have the same effect in terms of Preconditioning. However, if charging on Level 1, the preconditioning consumption is higher than the charge rate, therefore potentially the vehicle will not be fully charged at the departure time.

Q. How early before the departure time will the vehicle begin to precondition?
A. When using the vehicle preconditioning menu, it will depend on temperature, but generally 30-40 minutes prior to the set departure time the cabin preconditioning will start, and the battery preconditioning will start 150 minutes prior to that.

Q. Will the car ever turn a battery warming on by itself if the battery temperature gets critically low. For example, the car is parked outside and plugged in and the battery temperature drops below 30 degrees, will the preconditioning turn on and warm the battery up without owner intervention?
A. No. User intervention is required for battery preconditioning. If the battery temperature is very low, it will be outside its normal operating temperature. As a result, the power output and usable energy of the battery will be reduced.

Q. How about if it gets critically hot � over 105 degrees?
A. If the battery temperature is higher than the optimal operating range and preconditioning is activated, the battery can be cooled. This is not very common due to the fact that the battery is such a high thermal mass, is located close to the ground, and is not exposed to direct sunlight.

Q. Why is it that sometimes after preconditioning (plugged in) the car is left at 97% or 98% SOC? Why doesn�t it fully recharge the car to 100%?
A. When preconditioning using a Level 1 charger, the car will always be below 100%. It could be about 80% or lower.(Because it uses more energy than the 120v source can provide) When using a Level 2 charger, the SOC could be slightly under 100% as the vehicle electrical load stays somewhat constant while the charger will switch off and on.

Q. Will battery cooling occur automatically while you are driving when the battery temp exceeds a certain set point?

A. Yes.

Q. When battery preconditioning is being performed, what is the battery temperature that the vehicle is attempting to achieve?
A. The battery is warmed or cooled to bring it close to or within the optimal operating range of 25-40C (77-104F)

I'm certain that the vast majority of i3 owners are not aware that the car does not initiate battery preconditioning unless they set the departure time at least three hours in advance. Also, based on feedback I've received here, many i3 owners aren't aware that they aren't preconditioning the battery if they initiate precon by pressing the small fan icon at the bottom of the main state of charge screen on their iRemote app. By doing so, that only initiates cabin warming or cooling. In order to precondition the battery as well as the cabin from the app, you must set a departure time at least three hours in advance and then slide the preconditioning tab to "on." Don't feel bad if you own an i3 and didn't know all this, most client advisers at many BMW dealerships don't know it either. It's a little confusing at first, and honestly I think the app could be made a little more intuitive, but once you understand how it works, it's easy to set. You can also set the departure times and precon from the iDrive in the car.

Using the "Activate Climate Control" app feature on the left only preconditions the cabin. To precondition the battery as well as the cabin, use the "set departure time" feature which is accessed by pressing the small clock tab on the top right of the state of charge display screen. Once you set the departure time, you also need to slide the precondition tab to the "on" position.

Living in northern New Jersey I get to experience a range of temperature extremes and using the preconditioning feature is definitely helpful. We just finished the coldest month I can ever remember and it seemed just about every day I was leaving the house in the morning with temperatures in single digits or below zero. One day it was actually minus eleven degrees Fahrenheit when I began my morning drive. Even though my car is parked inside my garage, when it's this cold the battery temperature drops to levels that severely impact its performance and the range is reduced. I noticed I could add as much as eight to ten miles to my range if I used the preconditioning on the coldest days. It's also nice to get into a warm car, and this enables you to turn down the cabin heat a bit, which additionally helps extend the range. I found that if I allowed the preconditioning to warm the cabin, I could then lower the cabin heat, or even turn it off for a while and just use the heated seats which use much less energy than the cabin heater. 

I hope this helps i3 owners understand a little more about preconditioning. If you have more questions, please leave them below in the comments section and I'll do my best to answer them.

The Norby's "Driving to Net Zero Energy Challenge" Starts off Strong!

My i3 is powered by electricity generated by my home solar array. EV+PV is really a fantastic combination and one that I believe will be fairly common in the near future.  So how can you possibly top that? How about by getting two i3s and powering both of them plus your entire household's energy use by your  solar array! That's exactly what the Norby's are attempting to do.

I have frequently written on my blogs how one of the best part of being in BMW's e-mobility test program for the past five years has been meeting and interacting with many of the other people in the program. Together we learned how to live with the issues that test cars frequently have, we built up our own support network and we simultaneously realized how fantastic driving electric was. It was a really a great experience and one that was nothing short of life changing for many of us. 

While I've literally made hundreds of acquaintances in the program, there are a few people who I've really connected with and now consider friends, and one of them is Peder Norby. Peder and his wife Julie live in Carlsbad, California and went from MINI-E to ActiveE to BMW i3, just like I did, only they went one step further and got two i3s! Like me, the Norby's power their electric cars with clean energy from their rooftop solar array. However even though our systems are about the same size, their array provides about 1/3 more energy than mine does because of the location (sunny Southern California) and orientation of the arrays. 

This year, Peder and Julie began a year-long net-zero energy challenge. They are attempting to live the entire year with their solar array providing all the energy they need to power their home and both of their cars. I believe this is a fantastic story and a glimpse into what the future has in store. Peder has been updating the progress on his i3 blog but now that he is one quarter of the way through the year, I asked him for permission to post his progress here and he happily agreed.  Below is a little introduction to what the Norby's are doing followed by the three month update. 

It�s hard to get this down to a sentence or two, but when we built our home in 2005,  our ethos was to partner with nature, harvesting the gifts of nature, building the most efficient home possible.

In doing this, we wanted to elevate, we refused to compromise or lower the enjoyment of our life and the caliber of our dwelling, we refused to reduce our life to living in a small cave with one solitary light bulb, solely for the sake of efficiency.

Our desire was to express ourselves artistically, with the highest quality materials, design and comfort in the size home needed to accommodate our family and friends, while partnering with nature, being as efficient as possible. We wanted to live in a net zero energy home, harvesting food and drink from our land. Not big or small, not right or wrong,  just our home.

The idea is a simple one: Harvest sunshine from the roof of your home to provide 100% of the power needed for your home and the two cars in the garage. That is our goal in this "Driving to Net Zero Challenge.

 

The 12 month documented journey began May 15, 2014. Three months in, things are looking pretty good:

Update Month Three. We're killing it!

The idea is a simple one, harvest endless sunshine from a small portion of a roof to provide 100% of the energy needed to power a home and two cars with zero utility cost, and zero gasoline cost.

Summary:

• 1/4 of the way through the year,  -167 kWh and a $468 credit.
• Stats, Stats, Graphs, Graphs. 
• We're killing it! Ready to make a projection!
• Our French import.

We estimate that we will be -$800 by Oct/Nov

Solar PV production holding steady at 1326 kWh

Electricity use for the two BMW i3's rose to 478 kWh for the month

We have a credit of $315 for the first seven months of the year

1/4 of the way into our "Driving to Net Zero Energy" challenge and as they say in political election coverage:
"I am ready to make a projection and call this race"

We will be below zero in utility cost and gasoline cost providing the energy for our home and guest house, and the two cars in the garage driven a total of 24,000 miles a year.  In fact we are so far ahead we will accomplish this goal four months earlier than planed with the January 2015 true-up bill from our utility. 

Our natural gas cost for a year is $301.27

We estimate at the true-up bill that we will have a credit of $400 to $450 for our electrical use and a cost of natural gas of $301 for the year thus  -$100 to -$150 in total energy cost for the year.

How about total cost?

As I mentioned in my first post in May, an asterisk is required regarding the cost of energy as our utility does not let us carry over our electricity credit to our natural gas cost.  Essentially our valuable peak hour electricity that we do not consume will be a gift to our utility.  As the years go by we will most likely convert one or two of the natural gas appliances at the end of their useful life to electric in order to reduce the natural gas bill by using our excess electricity credit.

Where are we with energy usage and gasoline cost now compared to 2007 when we began this path to energy independence?

In 2007 our energy cost were:

$3,800 a year in electricity
$   300 a year in natural gas

$2,800 a year for Julie's Infinity G35 gasoline

$2,400 a year for my Volvo S60R gasoline

Total:    $9300 a year in energy cost.  ($792 per month)

This is not far off the statistical norm for a US family which uses an average of 11,000 kWh per year ($3,060 at SDG&E rates) and $2912 for gasoline according to the 2012 EPA statistics.

In 2014 our energy cost are:

$      0 a year in electricity*

$  300 a year in natural gas

$      0 a year in fuel cost for Julie's BMW i3

$      0 a year in fuel cost for my BMW i3

Total $300 a year in energy cost. ($25 per month) 

* we donate $450 worth of electricity back to SDG&E.

You can see how quickly that $9000 a year in energy cost savings will pay off a $30K Solar PV system, $15k in extra construction cost for a thick well insulated home, efficient appliances and led lights and $1000 for a EV charging station in the garage.  We have calculated from the installation in January of 2007 we reached the payoff point in April of 2012.

From April 2012 and for the next few decades, we will have essentially zero or de minimus cost for energy saving us $200k to 300K in energy cost with escalating utility and gasoline cost.

How about total usage?

Julie and I live normal lives, things come up and situations change. The interesting part of our Drive To Net Zero Energy challenge is that we are real people with a real life and not some demonstration house with nobody living in it.

We have been doing really great using a net total of -167 kWh of electricity (generation vs consumption) for the first three months of the challenge. We can extrapolate the prior four months of usage pre i'3s, assuming we had the efficient BMW i3's and the extra 1kw of solar pv production which would have saved us 225 kWh per month. We estimate that by May of next year we will be very close to a net of 0 total kWh used, +- 250 kWh per year which is a normal usage and weather variable.

The French Import.

I bet you thought it was a car :)

Julie and I have decided to make an impact on two young adults lives.  We are hosting through Rotary Youth Exchange, a 17 year old French student named Peroline for a one year exchange. By doing so, an American young man is traveling to France to begin his year as an exchange student in France living with Peroline's family.

Our household has now risen to four and the extra electricity that our 17 year old exchange student will use will most likely push us into the positive use territory.

Hosting a 17 year old young lady French exchange student for a year was not contemplated and is not a very good idea for the Drive To Net Zero Energy Challenge!

But life is life, unpredictable, wonderful and real.  We are very happy to have Peroline as part of our family for the next year and we're looking forward to driving her everywhere, using lots of electrons, to see the sights of our great nation.

Our goal remains Net Zero Energy usage as well as Net Zero Energy cost.
We'll see how the the next 3/4 of the year goes.

Imagine a better future and your participation in it.

Next Month:

• Charging stations and what's on the horizon.
• Our CHG emissions 
• Our version of GHG offsets

Thanks for reading and commenting.

(Past "Driving To Net Zero" articles on Peder's blog)

Energy Challenge Introductory Article

Mid Month Article: The Energy Grid

Update Month 1

Mid Month Article: Does your Gas Station Pay you to fill'er up?

Update Month 2

Bonus video:
Below is one part of a series of videos that Peder and I participated in. The video series is called "Wherever You Want to Go" and was produced by BMW back in 2011. BMW recruited Buzz Aldrin, Marissa Meyer, Robin Chase, Syd Mead, and many others to participate and Peder, Todd Crook and I were also chosen to because of our high level of participation in BMW's e-mobility program. The four-part series is available online and did a good job of opening the up a conversation about where we are going with regards to personal mobility. Take a look and see if you can spot Peder and me.  :)