Preconditioning off charger

[easports82]

Curious about the drain on the battery for preconditioning off the charger. I'm not plugging the i3 in every night because a) I don't drive enough daily to warrant it and b) the stupid Level 1 charger can't charge fast enough to stay within off-peak electric hours (level 2 ordered!). Not sure if it can be measured, but does preconditioning while not plugged in negate the benefit of preconditioning?

 

[jadnashuanh]

From a personal comfort factor, no. From a maximum range factor, yes. From my unscientific observations, when I precondition on my EVSE, I see current draws bouncing between 12 and 20A, and maybe near the end, dropping to around 5A. Given the time it is running the preconditioning cycle, I'd guess a maximum of 2Kw use, probably less most of the time, unless it's REALLY cold out. That's a pretty good hunk out of the battery capacity if you can't substitute power from the EVSE to do it (it's still batteries, but essentially no recharging is going on, just maintaining unless they weren't already fully charged).

Someone said that it doesn't precondition the batteries if you aren't hooked up to the EVSE, so that would limit the draw on them. That function may or may not need to happen as you drive, since using a battery generates some heat, you may not benefit as much from actively heating them when in READY or driving mode.

 

[NHi3REx]

First of all, being in southern CA, I'm not sure how much of a benefit you'd be getting from preconditioning in the first place. Being in NH, I've found preconditioning a must for my cold winter mornings.

Second, I'm still not certain if the car actually preconditions the battery if it isn't plugged in. Someone else here probably has this answer.

Finally, this hasn't stopped me from trying to figure this one out myself, and for my <20mi return trip commute (no charger at the office), I believe I've determined it to be a wash. Assuming the car can actually precondition the battery when its not plugged in, I would assume on longer trips it might be worthwhile. However, I'm thinking this would depend more heavily on the environmental conditions (ie Preconditioning in the cold will drain more charge vs in warmer weather). Additionally, even a cold battery warms up after putting some miles on it, which potentially negates whatever charge was lost preconditioning vs the reduced efficiency over those initial miles.

BTW, in case you were not aware, by simply hitting "Precondition" from the iRemote only preconditions the interior, You have to set a departure time with Preconditioning enabled to have the battery preconditioned

 

[stumbledotcom]

I'm not seeing any significant range difference when preconditioning vs. not so I've stopped bothering. In coastal California, the only reason to use the option is cabin comfort.

 

[pastyboy]

I'm not seeing any significant range difference when preconditioning vs. not so I've stopped bothering. In coastal California, the only reason to use the option is cabin comfort.

Are you setting from your phone? If you just use the drag up menu for pre-conditioning you only heat the cabin. To heat the battery you have to use the other menu where you set a departure time, then it will pre-condition the battery. I understand it can take an hour or more on colder mornings which is why you set a departure time and the car decides the time it needs.

 

[stumbledotcom]

Are you setting from your phone?

No. Setting from iDrive in car. I park underground so app commands don't get through at home. That's actually why I decided to stop bothering with it. I'd forget to disable preconditioning when I wasn't plugged in.

The key phrase in my statement was coastal California. Temperatures here in a narrow strip along the edge of the Pacific are so mild, so consistent that I've concluded preconditioning is pointless. In SF, it stays between 13° and 23°C (55° and 75°F) pretty much year round. It rarely gets hot and never gets truly cold; the last time we recorded an overnight low below freezing was 1996. I understand preconditioning is important in most of the world where winter happens but I (and the original poster) are lucky enough to live where it's irrelevant.

 

[NHi3REx]

I can attetest that preconditioning does make a significant different to those of us less fortunate ones living in winter climates..

During my inward commute (~17mi each way) with morning temps averaging let's say 10-20F, and preconditioning completed in my garage, I typically use roughly 25% of a full charge getting to the office. Whereas on the drive home, typically 5-10F warmer, without any preconditioning I usually lose nearly 35% additional charge (arrive home with ~40% remaining).

Now, as I mentioned earlier in this thread, I've tried scheduling preconditioning to run for my homeward departure, and I found that it cost me about 10% of my charge starting out. However, I made it home with roughly the same 40% charge remaining, which makes me think the battery preconditioning actually occurred even though I was not plugged in.

My next test is to dig through the service menus and actually check my various pre departure battery temps to confirm what's actually happening.

 

[jadnashuanh]

FWIW, the simple act of using the battery to condition the cabin will result in some heating of the battery pack, regardless of whether it is actively trying to do it as well. Same thing happens when you use any high current battery powered device (say a cordless drill)...the battery gets warmer as you use it.

 

[Boatguy]

Are you setting from your phone?

No. Setting from iDrive in car. I park underground so app commands don't get through at home. That's actually why I decided to stop bothering with it. I'd forget to disable preconditioning when I wasn't plugged in.

The key phrase in my statement was coastal California. Temperatures here in a narrow strip along the edge of the Pacific are so mild, so consistent that I've concluded preconditioning is pointless. In SF, it stays between 13° and 23°C (55° and 75°F) pretty much year round. It rarely gets hot and never gets truly cold; the last time we recorded an overnight low below freezing was 1996. I understand preconditioning is important in most of the world where winter happens but I (and the original poster) are lucky enough to live where it's irrelevant.

I'm in your same location, my i3 is parked less than 100' from the Bay. I do see an increase in mi/kWh when pre-conditioning. My consumption over the first 2-3 miles when I pre-condition is about half what it is if I don't. So maybe I save 1kWh, which improves my range by 1/18, or about 5% so maybe 4 miles? Not huge, but non-zero.

And then of course it's nice to get into a warm car in the morning.

 

[stumbledotcom]

…I save 1kWh, which improves my range by 1/18, or about 5% so maybe 4 miles? Not huge, but non-zero.

And then of course it's nice to get into a warm car in the morning.

I said the range difference wasn't significant to me, not zero. Four miles on a full charge is irrelevant when I average less than 14 miles a day. The fact that I forget to turn off departure time when I don't plug in (most nights plus my underground garage blocks control signals from the app) means I lost more miles to cycles when it wasn't plugged in than preconditioning saved. Regardless, I stand by my previous statement that in our climate, preconditioning is mostly about cabin comfort.

 

[Boatguy]

…I save 1kWh, which improves my range by 1/18, or about 5% so maybe 4 miles? Not huge, but non-zero.

And then of course it's nice to get into a warm car in the morning.

I said the range difference wasn't significant to me, not zero. Four miles on a full charge is irrelevant when I average less than 14 miles a day. The fact that I forget to turn off departure time when I don't plug in (most nights plus my underground garage blocks control signals from the app) means I lost more miles to cycles when it wasn't plugged in than preconditioning saved. Regardless, I stand by my previous statement that in our climate, preconditioning is mostly about cabin comfort.

Yes, I think we're in violent agreement.

 

[NHi3REx]

Thanks to some help from rtanov through another thread, I was able to access the battery temperature readings prior to departure and at the end of my commute with Preconditioning completed in the morning while plugged in and attempting to precondition on eth way home while not being plugged in.

The first, and expected result, was that attempting to precondition when not plugged in does nothing to precondition/warm the battery at all. Both days I found the battery was at -1C with and without preconditioning scheduled. This is in comparison to +10C and +7C for the same days after preconditioning was completed while plugged in at home.

Secondly, I noticed that during my ~18mi commute each way (mostly highway drivnig at 65), the battery temp only increased roughly 2C independent of preconditioning, which leads me to conclude that I'd need to effectively drain my entire charge before I'd get the battery up to the same starting temps after precondition is performed. (Note: these test runs were conducted in ~10-20F exterior temps and I would assume warmer ambient temps would result in quicker battery warming)

 

[Bunter]

Thanks to some help from rtanov through another thread, I was able to access the battery temperature readings prior to departure and at the end of my commute with Preconditioning completed in the morning while plugged in and attempting to precondition on eth way home while not being plugged in.

The first, and expected result, was that attempting to precondition when not plugged in does nothing to precondition/warm the battery at all. Both days I found the battery was at -1C with and without preconditioning scheduled. This is in comparison to +10C and +7C for the same days after preconditioning was completed while plugged in at home.

Secondly, I noticed that during my ~18mi commute each way (mostly highway drivnig at 65), the battery temp only increased roughly 2C independent of preconditioning, which leads me to conclude that I'd need to effectively drain my entire charge before I'd get the battery up to the same starting temps after precondition is performed. (Note: these test runs were conducted in ~10-20F exterior temps and I would assume warmer ambient temps would result in quicker battery warming)

I found the same. Preconditioning (set in car using a departure time) while plugged in raises the battery temperature to +10 but when not plugged in preconditioning (again set in car using a departure time) doesn't raise the battery temp. If you set a departure time in car but deselect preconditioning the battery temperature is pre-warmed as per with preconditioning selected (i.e. only if you are plugged in). My findings on this contradict what I thought I'd found before but it's possible that this has changed with a software update.

Bill

 

[Jeffj]

There is a ton of confusion around this, in particular since the term "pre-condition" is overloaded with 2 meanings. The 2 functions that are in discussion are heating/cooling the cabin and heating/cooling the battery.

The only way to heat/cool the battery is to have a departure time set (either from within the car or via the app) AND be plugged into a L2 (probably L3 would also work). EVSE AND have pre-conditioning selected (either in the car or via the app). If you are not plugged into an L2 charger, the battery will not get pre-conditioned. Note that if you are getting battery heating/cooling, you will also get cabin heating/cooling.

You can get cabin heating/cooling to happen independently of battery heating/cooling from a few more scenarios as there is no requirement to be plugged into L2 (in fact you don't even need to be plugged in at all):
- Having a departure time set (either from the car or via the app) WITHOUT having pre-conditioning checked
- Using the App to to just start cabin heating/cooling ad hoc by hitting the fan icon on the Status screen

A lot of people have assumed that hitting the fan icon on the app will pre-condition the batteries in addition to heating/cooling the cabin. This is not true.

While a complete pre-conditioning cycle (e.g. battery heating/cooling) can take up to 90 minutes depending on temperature, you can still "pre-condition" on an ad-hoc basis by using the app. If you are plugged into an L2 (requirement!), simply set a departure time a short ways into the future (15-30 minutes) using one of the 3 departure times available to you in the app and make sure "Preconditioning" is "on" in the app. Send the info to the car and (assuming a successful send to the car) the pre-conditioning cycle will start. It may not be enough time to fully get to optimal temperature, but its still better than nothing if range is a concern. I don this often on the weekends where I don't have a defined departure time, but I know I'll be heading out for errands, dinner, etc. As long as I think of this a half an hour in advance or so, I can get some pre-conditioning benefit.

 

[Bunter]

This is my summary of the situation on my vehicle.

Departure time set, precondition checked, vehicle plugged in = Cabin precondition and battery precondition
Departure time set, precondition unchecked, vehicle plugged in = Battery precondition only

Departure time set, precondition checked, vehicle not plugged in = Cabin precondition only
Departure time set, precondition unchecked, vehicle not plugged in = No discernible effect!

Activate auxiliary climate function from app = Cabin precondition only, even when plugged in.

Bill