Battery discharging while Stationary

[MarkH]

The voltage on the old battery was <1V and I'm now concerned at the time that the HV might be sitting at a very low charge while I wait for a replacement.

The HV battery's charge level shouldn't drop more than 1%/month while your i3 is parked. 12 V is required to close the HV battery's main contactor, so without 12 V, the HV battery is isolated and would only self-discharge.

Of course, if its charge was < 10% when your 12 V battery failed, it would be good to install a replacement 12 V battery ASAP.

No, the HV was sitting at 43% when I parked it but everything was dead in the morning, so I don't know how much trying to charge the 12V would have drained it before it finally fell over. Not much I can do about it anyway.

[alohart]

No, the HV was sitting at 43% when I parked it but everything was dead in the morning, so I don't know how much trying to charge the 12V would have drained it before it finally fell over.

There is little evidence that the HV battery pack charges the 12 V battery when an i3 is parked unless the HV battery is being actively charged or preconditioning is occurring, so I think your HV battery pack will be OK.

[MarkH]

All good. Thanks.

[MarkH]

Problems.

I picked up an identical replacement battery from the agents (90kms way) yesterday.
Put it on charge overnight.

Installed it this morning and reconnected the HV (through the fiddly HV connector).

All 12V systems seem to be working: unlocks and relocks everything; screens are alive.
When I press the "Start" button the expected displays light up: 40% charge; "Vehicle ready to operate"; Selector lever displays are alight.

BUT

When I try to select Forward, Neutral or Reverse - nothing happens.

Help please. Clearly the car is not driveable to the nearest agent.

Is there any "reset" protocol I have missed?

I do have a VPeake ODB device and BimmerCode loaded on my phone.
Can I use that to check what might be wrong?

[alohart]

When I try to select Forward, Neutral or Reverse - nothing happens.

Help please. Clearly the car is not driveable to the nearest agent.

Is there any "reset" protocol I have missed?

I do have a VPeake ODB device and BimmerCode loaded on my phone.
Can I use that to check what might be wrong?

Some other i3 owners have reported similar problems. The previous battery's low voltage could have resulted in several DTC's being set. Until these are cleared, an i3 might not function normally. Some have reported that the DTC's cleared while their i3's slept overnight. Others reported needing to clear the DTC's with an OBD reader. BimmerCode doesn't have this capability but BimmerLink does. BimmerLink can use your VPeake ODB device.

[MarkH]

OK. Fixed

One thing I thought I noticed was that the brake pedal felt hard when I went to engage the gear select.
I have now confirmed that that IS a relevant symptom.

Since all the 12V stuff was working as normal, I revisited the HV connection.

I disconnected and then re-connected the HV isolator.
When I tried things again - after that - it was fixed.

That HV isolator looks and feels like it came from the $2 shop. Very fragile and dodgy.

I have read on here somewhere (or on a link from here) that if the "isolation level" of your i3 is above 14-03-504 then "it is not necessary to deactivate the high-voltage system". Given the flakeyness of the HV isolator, I would heed that advice in the future.

So. Going again. Very relieved.

[MarkH]

Sorry, Art. Crossed your post. Seems DTC 's not the problem.
Thanks for your post.

[alohart]

Crossed your post. Seems DTC 's not the problem.

Good that you're back on the road! The HV disconnect can be tricky. I once thought that I had closed it but apparently hadn't quite. The resulting symptoms were similar to yours. Pushing the HV plug more firmly into its receptacle fixed the problem.