Energy Consumption During Preheat

[VintageMark]

Either way its still a 'design' question...

The Model S does this and a lot more... the engineering of that feature is not exactly battery pack patent level..

So it's a shame they didn't pay more attention to your feedback.

 

[Simon]

Thanks for sharing this Tom, to be honoust; your explanation does not suprise me. I thought it had to be just like you explain, but i didn't let me get ahead of myself making false accusations.

I don't expect it to be solved, but i will report it anyway. Maybe they can improve the behaviour with a software fix. If i was involved in solving this i would try to let the battery reach 100 SOC at departure time by postponing the final 3% charge up to the next programmed departure time when te preheating begins....

You seem to have a lot of experience with the activeE program; do you know it the BMW i3 has any restrictions in using the full 32amps? I am trying to figure out why mine is not exceeding 16 A.

 

[TomMoloughney]

Thanks for sharing this Tom, to be honoust; your explanation does not suprise me. I thought it had to be just like you explain, but i didn't let me get ahead of myself making false accusations.

I don't expect it to be solved, but i will report it anyway. Maybe they can improve the behaviour with a software fix. If i was involved in solving this i would try to let the battery reach 100 SOC at departure time by postponing the final 3% charge up to the next programmed departure time when te preheating begins....

You seem to have a lot of experience with the activeE program; do you know it the BMW i3 has any restrictions in using the full 32amps? I am trying to figure out why mine is not exceeding 16 A.

The i3 definitely isn't restricted to 16amps. If that is all you'll take then there is a problem. The onboard charger (BMW calls it the KLE) is comprised of two 16amp chargers wired together. So it is possible one of the two chargers in there isn't working. Believe it or not, this happened to my ActiveE when I first got it. I couldn't figure out why it was taking so long to charge and took it in for service and they immediately knew what it was.

 

[Lecram]

I received an answer from the dealer and he said:
If your car is connected to a charger, like the wallbox or another charger, it will take the power from the charger.
If you need the wall outlet charger, it will take the power from the battery.
Can someone of you confirm that?

 

[Simon]

I received a call from BMW i NL because of my questions concerning the charge amps. They explained to me that for me to reach 32A at home or at work, i need to use the quick charger; so i need to connect the charger to the lower and upper connection on the car. I think this is very surprising....
So i asked how to connect it, but they don't know.
As far as i know, the lower connection was for DC fast chargers only. Now they are looking into the plug/connection question.

Back to topic: In the same call, BMW i explained that only the wall-box will keep the SOC at 100% level during pre-heat because of special functions in the wall-box that other chargers don't have.

Let's say i am very surprised by these answers.

Can anyone with a wall-box confirm that their SOC is 100% after pre-heat
And let's collect experiences where the SOC is lower then 100% and mention your make and type of charger!

@Lecram: i do not understand what you mean by "wall outlet charger" compared to "charger, like the wallbox or another charger". What is the difference?

 

[BrianStanier]

BMW's replies are clearly not correct. The type-2 connector (top of the dual socket on the car) is all that is needed for 32A. The whole socket (if you have the dc option) is required for rapid charging.

 

[Simon]

OK, after a software reset and reload of the car, and a wall-box/evse change, i get the full 32 amps. Now i have to be aware my main fuse is not coming out ;-)

Now i can observe and investigate some more on the pre-heat function and behaviour

 

[Lecram]

OK, after a software reset and reload of the car, and a wall-box/evse change, i get the full 32 amps. Now i have to be aware my main fuse is not coming out ;-)

Now i can observe and investigate some more on the pre-heat function and behaviour

What main fuse(s) do you have? Single or 3-phase?

 

[SanSerif]

BMW's replies are clearly not correct. The type-2 connector (top of the dual socket on the car) is all that is needed for 32A. The whole socket (if you have the dc option) is required for rapid charging.

I wouldn't pay too much attention to BMW's answers at this point. Anyone who has a bit of engineering curiosity, observation, forum reading habits and has owned an i3 for a month or so probably knows far more about the vehicle than any i-advisor who's been on a training course.

Tom, your explanation of pre-heat makes perfect sense and explains what I'm seeing. Of course, I'd naively assumed there was a separate heating circuit; drawing power straight from the mains rather than via the battery. I can sort of see the engineering logic of a single path - mains to charger to battery to all power sinks - but a couple more wires and a bit of logic and the battery could sit in pristine 100% isolation while the fan heater/ac chuntered away slurping straight from the mains.

 

[Simon]

@Lecram: my main fuse is 40 amps, single phase, which doesn't really matter because the i3 is restricted to single phase charging only.

 

[Lecram]

@Lecram: my main fuse is 40 amps, single phase, which doesn't really matter because the i3 is restricted to single phase charging only.

For charging the i3 it doesn't matter, indeed. But it does matter for the total load of your electrical home system. If you charge at 32A and you use other devices like the laundry machine, oven, dish washer and so on, your main fuse can be overloaded. That's the reason that I switched to a 3 phase 25A main supply. The charger is connected to a single phase and no the other EVSE's are connected to the other two phases. If my car charges at 24A, there is no risk of overloading the system.
The other is is that your main fuse is 40A and the charger fuse a 32A. That's not "selectief" (I don't know the english word, may be "selective"). That means, in case of a short circuit in your charger, your main fuse can react as well and you will not have any electricity in your home until the "netbeheerder" replaces the fuse

 

[Simon]

I understand your concerns, thanks. But i have an automatic main fuse which i can reset myself. So my risks are not that high.
I will only use 32 A charging at home when i need to charge with a higher speed. For the rest i will have the cable setting at "middle" and i found out it still does a 22A.

 

[Lecram]

I understand your concerns, thanks. But i have an automatic main fuse which i can reset myself. So my risks are not that high.
I will only use 32 A charging at home when i need to charge with a higher speed. For the rest i will have the cable setting at "middle" and i found out it still does a 22A.

That's fine. I have to call Stedin in case of a melted main fuse.

 

[Simon]

Hi,

The dealer contacted me a few days ago and informed me that a software update is prepared by BMW to fix the issues we've experienced about draining the battery instead of wall power during battery pre-heat.

 

[DerfSdrawd]

c 8am this morning I used the remote key to start the pre-heat on my brand new i3 delivered on 11 April. It had been fully charged overnight from a Wallbox. Straight away the smart meter from which the Wallbox gets its power started drawing at c3kW so it looks like the current software on the car has sorted the issue. Certainly the range on the car after 30 mins of pre-heat (it's April in the UK :lol: ) was still at its max.

 

[Simon]

When activating the preconditioning manualy this is what happens, so you're right. But when you set a departure time, which in my experience is equivalent to "pre-heat the batteries", there is no power taken from the house. At least; in my case.
Do you want to check that for me?

My observations:
- half an hour before the set departure time the car starts to "work/live" but without taking power from the wall-box.
- 9 minutes before departure there is power taken from the wall box
- When the departure time is set WITHOUT preconditioning of the interiour, there is no power taken from the wall-box at all.
- When activating the preconditioning of the interiour manualy, power is taken immediatly.

 

[DerfSdrawd]

Hi Simon, I had a little play this morning and set a departure time for about 45 minutes in the future. The car was fully charged (green light around the filler cap) and I tried the procedure with and without ticking the "precondition" box.

In both cases the car drew power from the Wallbox - about 6kW with the box ticked and 3kW without. I'm going to the BMW dealer later today so I'll ask the "iGenius" (where did they get that idea from I wonder??) to clarify what it means but I expect you're correct in what you wrote below.

Will post what the genius says.

How long before we're talking about "jailbreaking" the cars? :lol:

Fred

 

[Simon]

Did, in both cases, the power consumption start at half an hour before departure?
This is good info to prove my case.

 

[DerfSdrawd]

Yes, as far as I could observe. What I did just observe is that with a departure time set for Monday 09:00 (and only on Monday not on the other days of the week) and with the precondition box ticked, when I plugged the car into the Wallbox at c 16:00, the time of full charge was shown as 09:00 and the little fan sign was on in the right had side of the display in front of the steering wheel. I could also here the fans running at the front of the car.

Still plugged in, If I unchecked the set departure time box, the time of full charge became 18:00 and the fans/symbol all stopped. That doesn't make sense to me given that there was no departure time set for Tuesday and surely it won't going to sit there with its fans running until next Monday morning!

At all times, it was drawing current from the Wallbox.

From what I saw this morning, it seemed that if you don't set off at or before the set departure time, the Wallbox stops charging but the heating continues so at that point it was using some of the battery range. I guess if you tell a German car that you are leaving at 08:35 that is exactly when you must leave!

Fred

 

[DerfSdrawd]

Tried it "for real" this morning - set a departure time last night. The car seemed to activate about 10 minutes before departure and deactivate about 5 minutes after (yes I was late leaving..). the Wallbox switched on and off with the car.

But after a 22 mile trip up the motorway the car is still showing 77% charge so the preconditioning didn't deplete the battery at all.

Fred