Had my i3 for <36 hours...

Had my i3 for less than 36 hours before it started generating all sorts of faults. First it started to complain that it wasn't charging and I should contact BMW support. I called them and started over to the service center, but I dropped off my kid at camp first. When I tried to start the car again after camp, it wouldn't start. It was throwing brake faults and all sorts of other faults. Eventually I got it started and was able to get to the BMW service center without getting towed.

They ran diagnostics and are replacing the EME computer. Also, the 40 amp low voltage battery (not the high voltage battery that drives the car, the other one) had to be swapped out with a 20 amp battery. While the EME sounds unfortunate, this battery thing is baffling to me.

Of course, the car being so new, these parts have taken over a week to get. The battery still isn't here 8 days later, they are hoping it will arrive Monday.

I'm hoping I get to drive my new car at some point. This sucks.

Wow, so sorry to hear. Is it a REx or BEV?

REX.

Similar issue here... Car threw a CEL after 3 days and when I took it in, it had 10 fault codes. Dealer took 6 days to get new software patch loaded to get rid of all the codes. Have the car back for 2 days now and it is running good.

Usually, when an Active E or the i3 had been reported has having some kind of conniption fit when it comes to (accurate and inaccurate) errors on the display, it has been diagnosed as having a low-voltage 12 volt battery.

The i3 uses a 390 volt main battery pack to power the electric motor, but almost everything else it uses runs off 12 volts. (Hey, BMW already built all those components for other models, so there's no need to design and build a 390 volt radio, turn signals, car horn, cabin lights, cigarette ighter, etc.)

Naturally, the (main) battery's controller system peels off a bit of that 390 volts, steps it down to 12 volts, and passes it on to the car's systems. Including in those systems is a tiny motorcycle-szed 12 volt battery to keep things awake while the car is, um, "off." The car's controller is supposed to maintain the 12v battery's charge, but when that system fails, or when the 12v battery starts dying prematurely, the drop in voltage starts triggering all kinds of odd messages.

If you insist on at least looking at it, the teeny 12v battery is viewable from the frunk. Open the front deck lid, remove the left-side (velcro'ed) cover panel, and look between the storage box and the windshield washer fluid reservoir (I think), way in the back, underneath the windshield dashboard, really. You'll recognize the battery more from its (small) motorcycle battery shape than seeing the battery terminals for fluid caps.

So far, replacing the 12v battery has been the cure -- I don't think anyone has actually reported that the original failure has been due to the car's controller system.

-- Ardie
This is a good reason to petition BMWs software enhancement team to add a feature to show the system voltage(s) somewhere.

Got it back today. That was 12 days.
---

Thanks Ardie for the explanation, that actually makes more sense than what the BMW guys were telling me.

The voltage of the 12V battery is visible in a hidden menu. Mine is 14.5V.

Frank

Ardie said:

...The i3 uses a 390 volt main battery pack

Click to expand...

Hi guys,
minor detail in this discussion, but still: the HV batterypack is supposed to be rated @ 360v.
I think it was Jeremy here who suffererd the first 12v problems, leading to all sorts of trouble, a month or 5-6 back...

Regards, Steven

fdl1409 said:

The voltage of the 12V battery is visible in a hidden menu. Mine is 14.5V.

Frank

Click to expand...

Basics of lead acid batteries, which include AGM (Absorbed Glass Mat) 'motorcycle' batteries means that simple knowledge of the voltage is not that useful. Example, what it being reported in the post above is a 12 volt battery at 14.5V so it is reading the 'float' voltage, which is stray unusable voltage. A defective battery, esp. an old worn out battery, will commonly read 13v to 14v or a bit more right off the charger. Put a load on it for a short time and then read the voltage under load and you might get, for example, 10.5 volts which = throw battery away. This is the common method of detecting a bad battery, test under load.
I would like to know two things,
first, how do you get to that hidden menu?
second, is there a way to put that 12v battery under load without the 360v battery in the circuit? Because if you could put the 12v battery under load for a little while and then get to that hidden menu you would have good information.

AviatorMan said:

fdl1409 said:

The voltage of the 12V battery is visible in a hidden menu. Mine is 14.5V.

Frank

Click to expand...

Basics of lead acid batteries, which include AGM (Absorbed Glass Mat) 'motorcycle' batteries means that simple knowledge of the voltage is not that useful. Example, what it being reported in the post above is a 12 volt battery at 14.5V so it is reading the 'float' voltage, which is stray unusable voltage. A defective battery, esp. an old worn out battery, will commonly read 13v to 14v or a bit more right off the charger. Put a load on it for a short time and then read the voltage under load and you might get, for example, 10.5 volts which = throw battery away. This is the common method of detecting a bad battery, test under load.
I would like to know two things,
first, how do you get to that hidden menu?
second, is there a way to put that 12v battery under load without the 360v battery in the circuit? Because if you could put the 12v battery under load for a little while and then get to that hidden menu you would have good information.

Click to expand...

I haven't dug around for it yet (and hope we don't have to). But I will say that I sure hope it's the same unit that is in my BMW K-1200GT--that gel battery lasted 7 years (though I did use the $200 BMW electronic charger on it during winter lay-overs) before I replaced it this spring.

Anyone familiar with MC batteries knows that is quite respectable.

This happens commonly in the Prius when the 12v battery is shot. Even on new cars as dealers tend to run down the 12v battery on the lot.

They best method for troubleshooting the 12v battery is to allow the vehicle to sit for at least 6hours since the last run cycle then check the voltage at the 12v battery terminals with the car completely off. Anything less than about 12.2v is not sufficient for max efficiency. Once you start seeing 11v or less you may throw all kinds of crazy codes.

Remember, just because a vehicle is brand new that doesn't mean the 12v battery is in perfect condition. Test it yourself before going to the dealer. The Toyota dealers often don't even check the 12v battery voltage then they keep your car for a week testing unrelated issues. I doubt BMW or GM are any better. *sigh*

F8L said:

This happens commonly in the Prius when the 12v battery is shot. Even on new cars as dealers tend to run down the 12v battery on the lot.

They best method for troubleshooting the 12v battery is to allow the vehicle to sit for at least 6hours since the last run cycle then check the voltage at the 12v battery terminals with the car completely off. Anything less than about 12.2v is not sufficient for max efficiency. Once you start seeing 11v or less you may throw all kinds of crazy codes.

Remember, just because a vehicle is brand new that doesn't mean the 12v battery is in perfect condition. Test it yourself before going to the dealer. The Toyota dealers often don't even check the 12v battery voltage then they keep your car for a week testing unrelated issues. I doubt BMW or GM are any better. *sigh*

Click to expand...

I agree. I noticed in the local BMW showroom that they had extensions cords to most of the cars on the floor. I asked and the answer was that people like to play with the electronics and it kills the batteries.

Here is a possible scenario. Car sits on the showroom floor and the battery goes dead and is left dead for awhile. A very small battery has small plates which can be destroyed pretty quickly by being left discharged for a period of time. Service "charges" the battery and it's enough to be able to deliver the car; but the battery has really been damaged by a period of extended discharge so it can't hold a charge. Techs misinterpret the myriad errors when all they needed to do was replace the battery.

But could you ever have that conversation with a tech on the service side of the dealership?