Delayed Charging mode.

[bkkanu]

I like the Active E menu for Delayed Charging. You set the timer when it should start the charging and plug the charger and that its. Now i3 does not allow you to do delayed charging unless you program the departure time as well as economy rate. I tried this once and it did not work. Has anyone found this to be an issue or resolution?
FYI: the portable charger or level 2 charger did not work with the car default setting as well. I had to change it to "max" setting. One would think the default setting should work as plug and play.

[Plug]

My delayed timer is inconsistent too and often the charging is starting too early. I have the 'Off-peak tariff' set for a 7 hour period overnight which is plenty of time to allow a full charge but it's regularly starting up to 90 mins early but not every time so I can't figure it out. It does the same for the 32A charger or the 10A 3-pin plug. I've taken to using the 10A charger with a timer-plug which is daft but it's the only way that I can ensure that I get a charge during the correct time.

This reminds me, I did send my dealer an email a few weeks ago asking about this but didn't get a reply so I think I'll contact him again.

[harttim1]

I have seen a somewhat similar behavior with my i3 REX....but only for a short period of time. I have delayed charging set for 12:05 am to 5:55 am and a planned departure of 6:30 am daily. This time frame corresponds to the off-peak charging time for my household electric plan in California. Tonight, I plugged the i3 in at 8:30 pm... there were "0" electric miles displaying and the car was running on the REX when I got home. The i3 immediately began to charge despite the delayed charging settings. The charging (at full 7.2 kW/h) continued until the iConnect App on my iPhone showed 8 miles of range or 10% charge and then it went to "Charging Paused" on the App. The vehicle will resume charging tonight sometime after 12:05 am. It would appear that the i3 wants to keep some level of minimum charge when power is available.

I have real-time monitoring software for my home electric meter and it also indicates that while the i3 could start charging at 12:05 am - the typical start time is around 2:00 am. The vehicle is drawing full power for sometime then there is a gradual step down for about an hour or so until the i3 is fully charged. My charging times are 3 1/2 hours or so when the battery is completely drained.

[acmik]

It would appear that the i3 wants to keep some level of minimum charge when power is available.
...
I have real-time monitoring software for my home electric meter and it also indicates that while the i3 could start charging at 12:05 am - the typical start time is around 2:00 am. The vehicle is drawing full power for sometime then there is a gradual step down for about an hour or so until the i3 is fully charged. My charging times are 3 1/2 hours or so when the battery is completely drained.

This is a great info, thanks for your input!

[dtuttle007]

Battery SOC management is a very interesting topic. I've measured my Volt's SOC with an advanced scan tool and found that the charge varies from about 20% to 85% SOC (a 65% SOC window). It's well known that GM was VERY conservative with the GEN1 Volt design. From all indications I've had zero battery degradation over 3.5 years and 40k miles with this conservatism. 85% SOC window sounds aggressive from the SAE papers I've read on Lithium batteries. The extremes of stress and impact to battery life seem to be at both extremes of SOC (near zero and near 100%).. but particularly at high SOC in hot temperatures. As a first guess, I would speculate that BMW keeps the battery below 90% SOC and above 5% and perhaps uses some temperature dependent algorithms. I wonder if winter charging gets skewed higher 10 to 95% and summer from 5 to 90%. It's interesting that with a REX that the control system would let the SOC fall enough to be concerned with over riding the lower bound SOC limit or delayed charging mode. Maybe they didn't want to have different software versions for the BEV vs REX... and the BEV has the priority of not stranding the driver and allowing the SOC to approach very low levels but as soon as possible the control software wants to get the SOC up to, say, 10%.
My first guess is that this is not some kind of error or software bug. I would bet it's intentionally designed that way.

[arlorose]

For the last three nights the car hasn't started charging on its own inside the low-cost time. I've had to fiddle with the remote app to get it to start charging.

Had been working flawlessly until now.

Pretty disappointing to have a software glitch like this after the A/C issues.

[ericblz]

I see this topic has been idle for a while, hoping to put out my issue for public comment...


I have a Clipper Creek level 2 charger which does not have a timer, since I assumed the off-peak hours charging would work fine. I regret that is having a timer on the charger would alleviate having to deal with the car's timing. It actually did work fine, until after I received the August software update.

I have discounted electricity 12 AM-5 AM. I set the car up with these hours as low cost charging. I also set a 5 AM departure time, but without preconditioning. The car's logic dictates that it have a full charge at departure, so it is possible it would start before low-cost charging if needed.

On a typical day I would come home and plug in the car around 5 PM. The charging indicator on the station clicks and turns on for a few seconds, then off. iRemote shows charging paused. If I am below 10% on the battery, the charging does run for a little while and then pauses which is normal.

Sometime between 9 and 11 PM I get an alert on iRemote saying charging error. I go out to the car and either the charging plug light around the receptacle on the car is off or flashing red. I also notice my car doors are locked. This may be a coincidence but I noticed it several times as perhaps related.

I then unplug the car and plug it back in. Sometimes this puts it back in pause mode as should be normal, sometimes it does nothing until I open the car door and close it again. Or do that and then unplug and plug again. Often then it starts whirring as if it is conditioning the battery and the charging light stays lit on the charger. I believe it does that for a while and then goes back to pause mode for some reason, even though it is well above 10% already.

I assume this is a deep software issue but if others are getting the same style of problem at least we can join forces. I've no idea how the dealer would debug this aside from keeping the car several days.

[Plug]

Hi ericblz,

That's interesting as it's very similar to what I'm experiencing too.

When I first reported this earlier in the year my dealer took my car in for 6 days but they couldn't replicate the problem. They also replaced my BMWi wallbox but the problem persists so they ran out of ideas and have been relying on advice from Germany. A few weeks ago I was forwarded a copy of an internal BMWi email discussing this problem (which I probably shouldn't post here) but I can say that they have had a lot of owners report this issue and they seem to be giving it high priority. They admitted they were struggling to isolate the fault but the email went into quite a lot of detail about what they are doing about it and it gave me good confidence that a fix will be forthcoming at some point so I'm happy enough to wait seeing as it's not stopping me using the car.

[ericblz]

Thank you, great info.

What's strange is that I did not experience the issue until the August software was installed...keep us posted if you get a fix.

[jadnashuanh]

One thing that may not be obvious unless you've dug into it, is that the i3's user visible SOC is not the 'real' SOC of the batteries...it is the normally usable range and BMW has a buffer built in at both the top and the bottom of the range. Someone said the upper buffer is there so there's room for regen if you leave with a full battery. SO, it's possible if your trip started on the top of a hill, you could get more power into the battery than it had when the EVSE and the car said it was full. Don't know if that's the full truth, but it at least sounds plausible. The bottom end buffer is for several reasons...batteries don't like to be discharged flat, and if there isn't at least some charge there, the logic to run the recharging cycle has to go through a different path to get some back before it can fully function and begin to use the full EVSE output. I don't remember the exact numbers, but it appears there's about a 5% buffer at each end of the SOC that is usable under normal conditions.