Battery discharging while Stationary

[MarkH]

Yeah, looks like that's what I'll have to do. No BMW dealer within 90km so I'll do the replacement myself and then get it registered. Biggest problem may be getting the correct replacement battery. I appreciate you sharing your knowledge.

 

[alohart]

Yeah, looks like that's what I'll have to do. No BMW dealer within 90km so I'll do the replacement myself and then get it registered. Biggest problem may be getting the correct replacement battery. I appreciate you sharing your knowledge.

Don't bother registering the replacement battery. According to a couple of BMW i-certified mechanics in a different group, battery registration does nothing in an i3 but record the replacement date, battery type, and battery capacity which don't affect the 12 V battery charging protocol as occurs in BMW's ICE vehicles.

Some have installed power sports batteries even though they aren't designed exactly like the i3's original auxiliary battery type. Try to find an AGM battery ideally with no less than 20 Ah capacity. It can't be much taller than the original battery due to space limitations. You could probably figure out how to attach the automotive terminals that could be removed from the original battery.

 

[MarkH]

It's good to hear that it doesn't have to be an exact match.
I have found some AGM batteries of 20aH and similar dimensions, but none have the breather tube.
How important is that?

 

[jadnashuanh]

When charging a lead acid battery, it can outgas hydrogen, which is highly flammable...best to vent it out and way from the enclosed spaces.

 

[MarkH]

That's interesting. Hydrogen is lighter than air, but the venting tube heads downwards :?

 

[alohart]

I have found some AGM batteries of 20aH and similar dimensions, but none have the breather tube.
How important is that?

I believe that AGM batteries are sealed with a pressure relief valve on each cell. A properly-functioning AGM battery cell shouldn't produce so much internal pressure that its pressure relief valve opens. However, when a problem that produces gas pressure occurs, the pressure relief valve should open to prevent the battery case from cracking, maybe somewhat explosively. That's when it would be best to vent flammable hydrogen gas away from inside the frunk which the standard vent tube does. However, the frunk isn't sealed, and there are fewer ignition sources in the frunk than in an Internal combustion engine compartment, so I think the fire or explosion risk would be minimal. I've read reports of i3 owners installing this type of battery with no reported problems.

Maybe you could determine the manufacturer of the dead battery in your i3. If so, maybe you could contact the manufacturer to learn whether there's a local retailer who could order this battery for you. That's what I did. However, I and the original battery's manufacturer are both in the U.S. which made things easier.

If I were in your situation, I would probably install a power sports battery while continuing my search for a battery with a vent tube. I wouldn't drive more than 180 km round-trip to pay a BMW dealer too much for the correct battery.

 

[alohart]

Hydrogen is lighter than air, but the venting tube heads downwards :?

True, but it would be under pressure when vented, so that would force the hydrogen to flow downward.

 

[MarkH]

It's the East Penn Manufacturing Co.
I've got it out and will take it around a few local suppliers tomorrow to see if anyone can source a direct replacement - otherwise find the closest "other" 20aH AGM that I can. I'll also call the nearest BMW dealer to find if they have a direct replacement and, if so, what cost
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. Murphy's law dictates that this failure must happen at the start of a long weekend!

 

[alohart]

It's the East Penn Manufacturing Co.

I'm surprised that a U.S. manufacturer would be the source 12 V batteries for i3's sold in New Zealand. I'm pretty certain that the 12 V batteries in European i3's aren't supplied by East Penn Manufacturing.

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.

 

[MarkH]

MarkH wrote: ↑
Mon Apr 05, 2021 11:17 am
It's the East Penn Manufacturing Co.

I'm surprised that a U.S. manufacturer would be the source 12 V batteries for i3's sold in New Zealand. I'm pretty certain that the 12 V batteries in European i3's aren't supplied by East Penn Manufacturing.

MarkH wrote: ↑

The car was imported into NZ from the UK. I got the battery manufacturer off the old battery that is now out of the vehicle.

 

[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.