Fisher99
Posts: 86
Joined: Sun May 12, 2019 6:24 pm

Re: My i3 is Dead

Mon Jul 08, 2019 3:30 pm

alohart wrote:
Sun Jul 07, 2019 11:22 pm
With the high-voltage system disconnected, drive readiness state cannot be entered, so nothing that requires this state would function. However, some lower operation state can be entered as indicated by the instrument screen turning on with a message stating that the high-voltage system is disconnected, so I think it's likely that the windows could be raised and lowered, but shifting into neutral might be possible only in drive readiness state.
So since the HV battery had a full charge, could I safely connect my portable 12v jump starter to the 12v battery without disconnecting the HV battery and thus be able to activate drive readiness, shift to neutral, and thus be able to move the car out of the driveway and into the garage? Or are you saying that there is absolutely no way to move the car if the 12v battery is dead?

Hmmm... I just browsed my manual and it definitely says not to connect a jump starter to the 12v battery with the HV battery engaged. It also says that the only way to "push" the vehicle is with the drive selector in neutral, but also says "If there are electrical malfunctions it may happen that you can't change the selector lever position". So I would infer from this that with a dead 12v battery you are just screwed and cannot move the vehicle? Seems to me that this could potentially be a significant safety issue, depending upon where you are when the 12v battery dies...

Fisher99
Posts: 86
Joined: Sun May 12, 2019 6:24 pm

Re: My i3 is Dead

Mon Jul 08, 2019 3:38 pm

alohart wrote:
Sun Jul 07, 2019 12:21 pm
Why would you want to install a standard flooded-cell lead acid battery that weighs probably twice as much as the 20 Ah absorbent glass mat battery? The 12 V battery doesn't have to have sufficient power to start an ICE engine at low temperatures. The i3's DC-DC converter turns on to provide ~14.3 V to the 12 V system whenever the 12 V system voltage drops below a certain level or the 12 V current load exceeds a certain level, so the 12 V battery isn't very stressed. When the DC-DC converter is on, the effective capacity of the 12 V battery is that of the Li-ion battery pack.
If I understand this correctly, you are saying that the DC-DC converter can provide 12v power when the 12v battery is unable to provide it? But then why was my car a brick when the 12v battery died? This has really bugged me, as it seems that with the HV battery fully charged, there should have been a way get 12v power in an emergency situation. But maybe it only does this if the car is already in an "on and functioning" state? It can maintain the "running" state as long as it is already turned on, but if you turn it off then the DC-DC converter can't perform this function> Frustrating!

vreihen
Posts: 128
Joined: Tue Apr 30, 2019 4:55 pm
Location: Orange County, NY (FN21vm)

Re: My i3 is Dead

Mon Jul 08, 2019 5:35 pm

I'm pretty sure that the i3 uses a main contactor solenoid on the traction battery circuit, which requires the 12V battery to engage and in turn connects the traction batteries to the car and powers up the DC-DC converter. At that point, the 12V stuff is being powered by the DC-DC converter and not the 12V accessory battery.

BMW does not recommend using a jumper pack in lieu of a dead/failed 12V battery, so that is not an option for those who play by the book.

As for the ability of a dead 12V battery to leave a car stranded and unable to move, that's just one way it can happen. A week after I picked up my i3, the charger port locking solenoid failed. I could not remove the OUC cable from the car, and in a catch-22 it will not go into drive readiness mode or allow shifting to neutral until the charge door is closed. Roadside assistance had to drag it onto a flatbed with their winch, leaving two ruts across my front lawn from the locked rear wheels digging into the grass.....

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2015 BMW i3 BEV, Giga World, Tech and Driving Assistant packages, 15K miles

Fisher99
Posts: 86
Joined: Sun May 12, 2019 6:24 pm

Re: My i3 is Dead

Mon Jul 08, 2019 6:39 pm

Thanks VREIHEN for that disturbing information. :shock: One more thing for me to be paranoid about... :D

alohart
Posts: 1686
Joined: Sat Nov 01, 2014 7:36 pm
Location: Honolulu, HI

Re: My i3 is Dead

Mon Jul 08, 2019 11:02 pm

vreihen wrote:
Mon Jul 08, 2019 5:35 pm
BMW does not recommend using a jumper pack in lieu of a dead/failed 12V battery, so that is not an option for those who play by the book.
I wonder whether this information is outdated based on the note here regarding 12 V battery charging:

"If the integration level in the vehicle is up to and including 14-03-504, then the high-voltage system must be deactivated.

If the integration level in the vehicle is 14-03-505 or more recent, then it is not necessary to deactivate the high-voltage system."

Integration level 14-03-505 was released as a system software update in March, 2014, so almost all i3's must be running system software that should allow a 12 V battery charger to be connected safely without deactivating the high-voltage system.

Personally, I still avoid connecting a 12 V charger without first disconnecting the high-voltage system disconnect switch to avoid potentially expensive damage to the DC-DC converter and other high-voltage electronics. However, others have reported jump-starting without any negative consequences.
Aloha,
Art

2014 BMW i3 Arravani Grey, Giga World, Tech + Driving Assist, Parking Assist, DC Fast Charging, JuiceBox EVSE

Fisher99
Posts: 86
Joined: Sun May 12, 2019 6:24 pm

Re: My i3 is Dead

Tue Jul 09, 2019 11:42 am

vreihen wrote:
Mon Jul 08, 2019 5:35 pm
[snip]
As for the ability of a dead 12V battery to leave a car stranded and unable to move, that's just one way it can happen. A week after I picked up my i3, the charger port locking solenoid failed. I could not remove the OUC cable from the car, and in a catch-22 it will not go into drive readiness mode or allow shifting to neutral until the charge door is closed. Roadside assistance had to drag it onto a flatbed with their winch, leaving two ruts across my front lawn from the locked rear wheels digging into the grass.....
[snip]
I wonder if there is a way to disable the charge cable lock, to prevent the possibility of this happening? While it's nice to have the cord locked if you leave the car charging in a public place, I think I'd give up that security for the security of knowing that a failed solenoid could strand my car. I just took a quick look and I don't see anything visible that moves when you lock/unlock the car, so it must be something further back behind the charging port that "grabs" cord when the vehicle is locked.

vreihen
Posts: 128
Joined: Tue Apr 30, 2019 4:55 pm
Location: Orange County, NY (FN21vm)

Re: My i3 is Dead

Tue Jul 09, 2019 12:40 pm

If you look at your OUC connector, there's a rectangular depression on the top of the hook lever. The car's locking solenoid comes down from the top of the socket and jams that, so you can't push the release button to remove the connector.

My health situation prevents me from tearing the fender off and seeing if there is a simple way to insert a small shim/spacer between the solenoid and socket so that it can't reach the hook lever.

I read somewhere that it is possible to trick the solenoid into thinking that it has engaged and bottomed out by locking the doors while holding the charger release button and with the connector not quite seated in the socket. Take a look at the top of your OUC hook lever and it will make sense. I wasn't sure if that would cause more damage to the solenoid over time, so I'm probably never going to try this.

FWIW, there is an emergency blue plastic release cable in the passenger side rear door jam. The knob snapped off of mine when I pulled it, and others have reported that the blue plastic cable snapped on them when they tried to use it. Maybe the best attack is to see if it is possible to drill a small access hole inside the charge port door's black splash guard that provides access to the emergency release lever using a screwdriver or something? Cover it with black electrical tape, and nobody will probably ever notice it.....
2015 BMW i3 BEV, Giga World, Tech and Driving Assistant packages, 15K miles

Fisher99
Posts: 86
Joined: Sun May 12, 2019 6:24 pm

Re: My i3 is Dead

Tue Jul 09, 2019 1:47 pm

Good to know about the manual release for the flap and the cord, but a bit discouraging to hear that they are prone to breaking.

Just found out some interesting stuff when I went out to take a look at this:

If the cord is plugged into the car but not into a power outlet, locking the doors doesn't lock the cord. The cord locks when you plug the cord into a wall outlet. However, unplugging the cord from the wall outlet does not unlock the cord from the car. You have to unlock the doors for that.

Also, I just noticed that my OUC has a broken latch! The part that would latch to the car is completely broken off. You can simply unplug the cord while the vehicle is locked and charging (without even pressing down on the unlatch button). This tells me that the pin that come out over the top of the latch to keep it from unlocking doesn't care whether the cord is actually there or not. So, I am guessing that it wouldn't be that hard to use my Dremel tool to modify my TurboCord so that it still latches but the pin doesn't keep it from unlatching. I hadn't noticed this before because I use my TurboCord for charging rather than the OUC.

Of course, as I think about it more, modifying the cord's latch probably doesn't actually solve the problem. If the solenoid is deployed then the car will probably still think the cord is plugged in even though it isn't, so still would not let you engage the drive system. You would still have to have some way to get the locking pin to retract. I just tested by connecting my OUC with the broken latch, starting a charging session, and locking the car. Then pulled the OUC out of the socket. I can see the pin that has extended and you cannot simply push it back in, as the solenoid is still holding it out. Maybe with enough force you could push it in, but I wasn't willing to try that.

vreihen
Posts: 128
Joined: Tue Apr 30, 2019 4:55 pm
Location: Orange County, NY (FN21vm)

Re: My i3 is Dead

Tue Jul 09, 2019 4:39 pm

Was the green lights around the charging port still on solid green when you disconnected the OUC from wall power? Mine went onto the tow truck with a solid green light, and the house end of the OUC stuffed into the passenger side window.

Anyway, I think that it is a better idea to defeat/delete the solenoid, in case you ever use a charger on the road in an emergency. The last thing that I would want is to be locked to a DC fast charger.....
2015 BMW i3 BEV, Giga World, Tech and Driving Assistant packages, 15K miles

Fisher99
Posts: 86
Joined: Sun May 12, 2019 6:24 pm

Re: My i3 is Dead

Tue Jul 09, 2019 6:12 pm

Not sure about the light. I will have to check again.

I agree that defeating the solenoid lock would be the correct approach. I know absolutely nothing about electronics but it would seem that one could remove the panel to expose the solenoid and wire in some sort of override switch. Which makes me wonder how the blue emergency unlock cable works? Is it mechanical or electrical? That would probably be a good place to start exploring. Or maybe the solution is to simple replace the current emergency unlock cable with something more substantial and less prone to breaking. BMW already has the solution to the problem. Just find a way to make it more robust.

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