Low cost charging - not delaying

Hello,

I've set up low cost charging and set the low cost power interval from 2 AM -> 5 AM. I also set the departure time to 5 AM but have preconditioning to that time turned off.

Also level 1 and level 2 charging levels have been set to maximum.

I just plugged the car in at about 2:30 PM or so, I'm not sure the exact time. When I plugged the car in, the SoC was low - maybe 8%. It's now 3:50 PM and the SoC is at 42%. The car has been charging the whole time.

I have a Clipper Creek Level 2 charger, the 32 amp model. (good unit BTW, works fine)

So... I think I've found a SW bug. Iv'e used the "low cost charging" before several times and it was indeed delaying the charge time until some time in the middle of the night (I know this because I can see power consumption in my house to 15 minute increments from my power company - trust me, you can see when the car is charging). So it's not always messed up. Some times it works.

I have 2 theories:
1) there is a 24-hour time bug; the time is aliasing by 12 hours and the charging isn't distinguishing between 5 PM and 5 AM as times to complete charging, so therefor the car was trying to get fully charged by 5 PM.
2) the SoC was so low when I plugged the car in that the SW determines it should charge to some minimum SoC even though it's not currently a "low cost" time. Then when this minimum SoC is reached, the charging doesn't stop and wait again until the low cost power window opens up.

Anyone else seeing the same thing and/or figured something else about this?

Any suggestions for changing what I'm doing?

(as a first step I opened up the low cost power window to 1 AM - 5 AM)

Since way back when, I've always opted for a 24-hour readout on my clocks - it's non-ambiguous if you forget to notice the am/pm tick in the menu.

WRT low-cost windows...It's been said that if the window isn't large enough for the car to get to 100% within that window, it will start earlier rather than leaving you with a less than full charge. I've not tried it, so can't confirm how mine works. Being retired, I don't have a regular schedule, and I do not have a separate meter to make off-peak power use useful.

So I just opened the low cost charge window by about 2 hours and also set the departure time to a different time than it was - closer to when I would actually leave on a weekday.

Unplugged the EVSE, then reconnected a few minutes later. Delay now appears to be working to low cost hours.

I'll monitor and see if the problem reappears.

Seems odd if the car thinks it can't fully charge in the low cost window given (because the supplied window is too small), then why doesn't it figure out how long it thinks it needs and then start there, rather than starting now and going until it's full? That is, charge at the back end of the total available time instead of the front end. That's why they call it a bug.

Just did the same thing yesterday - plugged in with recharge set to "low cost charging".

when plugging in, it was at 7% SoC. Car charged up to 22%, I unplugged it and then replugged it in a couple seconds later. Then it went onto delay mode.

BMW SW guys... please fix this. To me it's a bug. I want to charge when I want to charge. If the car is deciding that it has to charge because the initial SoC is too low, then fine, have it charge to some "good" level (I would hope this is some low level like 10% SoC), and then shut it off, then continue to full charge during the programmed low cost charging window.

I'm beginning to regret not getting a smarter EVSE if the car is going to have bugs like this in its SW routines.

Is it not possible to use the low cost charge window to limit the charging time regardless of the starting and ending charge levels? I.e., is it not possible to charge for only 3 hours total by setting a 3-hour low cost charge window? I don't want to routinely charge to 100%. I typically want to charge to ~80% because I believe that battery pack life will be increased by not repeatedly charging fully and then leaving the car parked at 100% charge. This seems to be common knowledge in Li ion battery circles, but I've read nothing about this in the (disappointing) owner's manual. I realize that the i3 does not charge to its battery pack's full 22kWh capacity, but I'm sure that it doesn't allow the battery pack to be fully discharged either which could damage the pack. I don't know what charge range the i3 allows (e.g., ~14.5% is held in reserve, so 5% - 90% or 10% - 95% would be ~18.8 kWh).

It's my understanding that the i3 will attempt to charge to the 'user' indicated 100% if you plug it in, regardless. IOW, it will try to achieve that level, regardless of the low-cost charging window, therefore potentially charging outside of that window to meet that goal. I think that is a more reasonable thing. If you want to limit it to say 3-hours, you'd need an EVSE that you could control, either through programming it, or an externally controlled relay to shut it down so it couldn't provide power to the vehicle, regardless of what you'd programmed the car to do.

Given the warranty on the batteries, I'd not really worry about it. In fact, maybe hoping it failed before the 8-year, 100K mile warranty, and then, you'd get a new pack with probably greater capacity. Certainly, that's a gamble, but they've had a lot of miles and years figuring out how best to recharge their battery pack in the i3.