Fisher99
Posts: 269
Joined: Sun May 12, 2019 6:24 pm

Battery Pre-Conditioning

Fri Nov 08, 2019 11:01 am

Would one of you knowledgeable people please educate me regarding battery pre-conditioning? I'm heading into my first winter with the i3 and now the temps are getting down into the mid 20's and low 30's at night, with a few nights already in the high teens. I know that conditioning takes energy out of the battery, so will reduce driving range, so I would like to pre-condition the batteries while the i3 is still connected to my L2 charger at home. I had originally thought that the "climatize" feature would also pre-condition the batteries but I recently saw a post in another thread that seemed to indicate that it doesn't.

So, some questions: Does climatizing pre-condition the batteries? If not, is there a way to pre-condition the batteries while still attached to my L2 charger? And if I can indeed pre-condition the batteries, how long should I expect that to take when the temps are in, say, the mid 20's to low 30's?

Thanks.

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MKH
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Re: Battery Pre-Conditioning

Fri Nov 08, 2019 11:10 am

To precondition the HV battery pack, set scheduled departure times in your menu. The car will start the preconditioning 150 - 190 minutes or so before the departure time you set - actual time I think depending on temperature, etc the computer determines it needs to complete the preconditioning (while plugged in) . Climatize just warms up or cools the cabin and takes 30-40 minutes.
Mark H.
2015 i3 Rex, Capparis White, Tera World, Technology & Driving Assistant, Parking Assistant, Harman Kardon Audio System, 19 inch 427 wheels, EVoInnovate EVSE

Fisher99
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Re: Battery Pre-Conditioning

Fri Nov 08, 2019 11:31 am

Bummer. That doesn't really work for me since I'm a retired guy and don't have a set schedule for when (or even if) I might want to leave the house in the morning.

However, as I am pondering this, I wonder if there would be any merit in setting, say, an 8:00 AM departure schedule, to pre-condition the batteries even if I might not be going anywhere until later in the morning. Of course if it is still in the 20's or 30's, I wonder how long the pre-conditioning would be good for before it would need to be done again...

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MKH
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Re: Battery Pre-Conditioning

Fri Nov 08, 2019 12:11 pm

how long the pre-conditioning would be good for before it would need to be done again
Preconditioning would last however long it takes the battery pack to cool down in whatever the current ambient temperature is. Basically preconditioning is just warming the battery pack up (or cooling it) to best operating temperature. Optimum temperature for the battery pack is 25 to 40 degrees Celsius, or 77 to 104 degrees Fahrenheit. The further off the optimum temperature the battery pack is, the more the range is affected.

Be aware that preconditioning won't start at all, unless there is at least three hours available before the set departure time, and the car is plugged in. If the car is not plugged in, only cabin climatization occurs.
Mark H.
2015 i3 Rex, Capparis White, Tera World, Technology & Driving Assistant, Parking Assistant, Harman Kardon Audio System, 19 inch 427 wheels, EVoInnovate EVSE

Fisher99
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Re: Battery Pre-Conditioning

Fri Nov 08, 2019 12:37 pm

Interesting. I think I might set a 10:00 AM departure, since I rarely drive anywhere before then. And on days that I do head out a bit earlier, at least the battery would be partly pre-conditioned. Wish I had room to keep the i3 in the garage, but don't want to move out either of the other 2 vehicles.

This is good info. Thanks!

electronchaser
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Re: Battery Pre-Conditioning

Fri Nov 08, 2019 4:01 pm

Fisher99 wrote:
Fri Nov 08, 2019 12:37 pm
Interesting. I think I might set a 10:00 AM departure, since I rarely drive anywhere before then. And on days that I do head out a bit earlier, at least the battery would be partly pre-conditioned. Wish I had room to keep the i3 in the garage, but don't want to move out either of the other 2 vehicles.

This is good info. Thanks!
Just something I came across through trial and error, because I too have an undefined departure schedule, daily.

So I generally leave the pack to charge to about 90% full, and then EVSE cuts off. But before departure I go in via the app and start charging again. Typically I'll do this about 30-40 minutes prior to departure, and I've noticed pretty much the same range doing it this way, rather than setting a preconditioning timer. It also saves electricity, because you're using electricity to both fill the pack, and warm it (charging batteries warms them up significantly). For more data points, I've noticed the car still pulls 6+kW until about 94-95% then tapers down to 2.5-4kW until 100% full. When I used to do the precon, i believe it pulled about 2kW from the mains to heat the battery. I'd rather put that 2kW into the pack and heat it at the same time. Give it a try.
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jadnashuanh
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Re: Battery Pre-Conditioning

Fri Nov 08, 2019 8:07 pm

If you're also conditioning the cabin, I've seen mine drawing about 20A. The battery electric heater is a 1Kw device. Depending on how hot or cold it is, conditioning the cabin can take a fair amount, but it only runs for about 20-30 minutes just prior to your programmed departure time.

While plugged in, if you just tell the i3 to condition the cabin, it may or may not activate the charging. There's some hysteresis, so the level has to drop a bit before it kicks in. FWIW, it will not warm the batteries unless it's plugged in.
Jim DeBruycker
2011 535i x-drive GT, 2014 i3 BEV

Fisher99
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Re: Battery Pre-Conditioning

Sat Nov 09, 2019 11:16 am

Interesting approach, but unfortunately my EVSE doesn't have the ability to stop charging at a set percentage, and does not have app control. But, I could use the BMW app to track charge percentage and manually disconnect the EVSE. Then plug it back in again in the morning an hour before leaving. Might give this approach a try, although it's likely that I'll get tired of the hassle pretty quickly. Maybe somewhere down the road I'll cough up the $$$ for a smart EVSE.

jadnashuanh
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Re: Battery Pre-Conditioning

Sun Nov 10, 2019 3:39 pm

If you have a home automation system, you should be able to find a 240vac power switch for your EVSE. Note, many, but not all EVSEs, will restart properly after a power outage. Some won't if the vehicle is still attached.
Jim DeBruycker
2011 535i x-drive GT, 2014 i3 BEV

Fisher99
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Re: Battery Pre-Conditioning

Mon Nov 11, 2019 11:21 am

A switch is an interesting idea but would only help with turning the charger off/on. I'd still have to manually track the charging percentage if I wanted it to stop at, say 85%. Even though my i3 sits outside, the charger is plugged into an outlet inside my garage, so it's fairly easy for me to unplug it and re-plug it without having to go out into the cold. I did this last night. Unplugged it at 85% and now this morning just plugged it back in. Charging started up as per normal.

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