Swapped 12v battery. Still drain error showing.

Lurker in the forum for years. First time poster. 2015 BEV i3

Got the dreaded increased battery drain error and the gradual wacky errors until she was undriveable. Swapped 12v battery with new oem from Remy (east penn) and she was revived (drives,etc.) but I’m still getting an increased battery drain error. Could I have another more sinister issue? Of course, now out of warranty.

Additionally, I have a juicenet charger that emails me when charging is complete. I’m getting alerts almost every hour with a re-topping alert telling me the i3 has been recharged, implying there may be a drain on the batt still. Any ideas on how to find culprit? Nothing plugged into any aux sources that I can find. Or are we in a stuck state and I need to do some sort or error reset. Any help or feedback is greatly appreciated!

Homan

Out of curiosity, did you re-code when you swapped the 12V battery?????

vreihen said:

Out of curiosity, did you re-code when you swapped the 12V battery?????

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No re-coding done yet. Is this a necessary step? I thought the error might still stick around after the battery swap, but I don’t understand why there is still a draw on the system (if the battery has been replaced)?

BMW says it is, so that the car knows to reset the 12V charge curve back to optimum for the new 12V battery.

Some i3 owners think that the whole battery-coding thing is a leftover from ICE/alternator days (or "stealership" money-grab), and doesn't really do anything for the i3's 12V aux battery.

Some i3 owners have swapped the 12V aux battery without coding, and claim that this proves that coding is not necessary.

Since your car had a logged fault that didn't go away after a 12V aux battery swap, I was curious if you had coded the battery to see if it validated any of the above beliefs.....

Has the car sat for 12 hours or so plugged in to the charger? Many have reported that it seemed to take their car overnight, plugged in to charge, for all car's ECM's to reset themselves after a dead 12v was throwing errors, and then swapped out.

MKH said:

Has the car sat for 12 hours or so plugged in to the charger? Many have reported that it seemed to take their car overnight, plugged in to charge, for all car's ECM's to reset themselves after a dead 12v was throwing errors, and then swapped out.

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It wasn't on for 12 when I was checking last night. When I get home this afternoon I will check for errors and report back. The real kicker is that my juuicenet is sending me less than hourly recharging reports of various charges. LAst one was just a half an hour ago. Seemingly every half hour to hour there is a charge being applied to the car. .001kwh added at 10:30AM, .19kwh added at 9:50am, .001kwh at 8:40, .188kwh at 8:25 and so on. I could see if like .001kwh was the only applied charge as though the ECU is assuming the battery is effffed, but I am occasionally even getting .216kwh recharge messages.

I hope to come back home tonight to some positive news, but it's not looking good right now. I'd hate to reset the ecu only to have to reset it again because of some other battery suck

Many modern cars and I think, all BMWs, use distributed processing and communicate over the CANBUS. When you do something, like press a switch, the switch generally doesn't perform that function, it sends a message to ac computer, and the computer sends a message to a module that performs that task.

If a module or the data bus is starting to fail, when, say, you shut the car off, a module or more may not get the message, and stays in full operational mode rather than going to sleep.

Given that the car is turning the EVSE back on every hour or so says that there is a fairly significant load. It could be as described above, or it could be a partial short that is draining things down.

The system likely has stored some fault code(s). While they can be misleading sometimes, on occassion, they will point you directly at where the problem is. A generic OBD II reader won't read the BMW specific codes, and may or may not help. At least a few places will scan your vehicle for free. I'd start there.

If you have a thermal camera, you might scan it over some of the modules (like under the rear seat, where there's a bunch of them). If done after the car has been off for awhile, if one is pulling current, it will be warmer.

Foxwell and others make a scanner that can read the BMW and OBD II codes. That might be cheaper than having the dealer do it, especially if you can find one on sale. ECSTUNING sells one from Foxwell branded as a Schwaben. THere are other possibilities.

jadnashuanh said:

Many modern cars and I think, all BMWs, use distributed processing and communicate over the CANBUS. When you do something, like press a switch, the switch generally doesn't perform that function, it sends a message to ac computer, and the computer sends a message to a module that performs that task.

If a module or the data bus is starting to fail, when, say, you shut the car off, a module or more may not get the message, and stays in full operational mode rather than going to sleep.

Given that the car is turning the EVSE back on every hour or so says that there is a fairly significant load. It could be as described above, or it could be a partial short that is draining things down.

The system likely has stored some fault code(s). While they can be misleading sometimes, on occassion, they will point you directly at where the problem is. A generic OBD II reader won't read the BMW specific codes, and may or may not help. At least a few places will scan your vehicle for free. I'd start there.

If you have a thermal camera, you might scan it over some of the modules (like under the rear seat, where there's a bunch of them). If done after the car has been off for awhile, if one is pulling current, it will be warmer.

Foxwell and others make a scanner that can read the BMW and OBD II codes. That might be cheaper than having the dealer do it, especially if you can find one on sale. ECSTUNING sells one from Foxwell branded as a Schwaben. THere are other possibilities.

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On my way home and I have to agree that something must be pulling load. I’m going to grab a Foxwell or one of the above brands and see if I can sniff it out. My local (st)(d)ealer quoted me 300 just to look at the bloody thing. I figure I’m in for a bad battery already at 140$ and a reader should get me where I need to be to find the rest.

Maybe I’ll get home and it will have miraculously sorted itself out by being left on the EVSE but I doubt it. At 2:00pm it was adding another .19kwh.

I’ll dig through the forums but is there a definitive top choice for in-depth ecu analysis specific to our i3s?

vreihen said:

BMW says it is, so that the car knows to reset the 12V charge curve back to optimum for the new 12V battery.

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vreihen, have you actually see this in writing from BMW, not from a web forum or a BMW parts shop?


Let's think logically about this particular owner's situation: A new 12v battery is installed, it's not coded, so the car is pumping so much electricity into it that the HV battery needs continual topping up? That's crazy -- there'd be a flaming hot ball of lava behind the frunk where the formerly new 12v battery used to reside!

I haven't seen anything in writing from BMW, either. The sources I find most legitimate say that for AGM batteries, (1) registration is purely a logging / QC measure and (2) it allows the user to indicate if a different capacity or chemistry battery has been installed -- something different from the original.

Members,

Appreciate all of your help. Sooooo, the car is still giving me the errors well after the swap. We are quickly approaching the 24 hr mark. Draw is still happening. I've fondled underneath the driver's side seat but haven't ran into any specific module which seems warmer than other components.

When I got home this afternoon, I ran to the closest auto parts store (O'Reilly's) and had them hook up their bosch scanner. Literally had the car in every mode (Ready, Off, D, P,N, and every other state I could think of) and their scanner wouldn't talk with it. Lovely. I chalked it up to a dodgy scanner.

No sweat, I'll just call a few BMW specialist shops around me to see if they'll have a look. I tell them the model and both of them (2 of the most prominent around here) tell me to go to the dealer. Did I mention the dealer wants a $300 diagnostic fee? Madness.

So I'm in limbo here. I do have an infrared thermometer I can dig up, but I feel like it would be a bit more efficient to scan the ECU first. Is the Foxwell the go-to scanner for these cars? Which particular model seems to play best with the i3?

Homansensei said:

Members,

Appreciate all of your help. Sooooo, the car is still giving me the errors well after the swap. We are quickly approaching the 24 hr mark. Draw is still happening. I've fondled underneath the driver's side seat but haven't ran into any specific module which seems warmer than other components.

When I got home this afternoon, I ran to the closest auto parts store (O'Reilly's) and had them hook up their bosch scanner. Literally had the car in every mode (Ready, Off, D, P,N, and every other state I could think of) and their scanner wouldn't talk with it. Lovely. I chalked it up to a dodgy scanner.

No sweat, I'll just call a few BMW specialist shops around me to see if they'll have a look. I tell them the model and both of them (2 of the most prominent around here) tell me to go to the dealer. Did I mention the dealer wants a $300 diagnostic fee? Madness.

So I'm in limbo here. I do have an infrared thermometer I can dig up, but I feel like it would be a bit more efficient to scan the ECU first. Is the Foxwell the go-to scanner for these cars? Which particular model seems to play best with the i3?

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Because I'm Mr. Impatient, I pulled the trigger on Amazon for the FOXWELL NT530. IS that OK?

Because I'm Mr. Impatient, I pulled the trigger on Amazon for the FOXWELL NT530. IS that OK?

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Loaded with the BMW/MINI software? Then yes. It is the updated version of the 510/520, which is pretty much the BMW go-to DIY scanner at home-use prices.

Normal TS procedure is to scan, make note of the fault codes, then use the scanner to clear the faults, and wait and see if any re-occur. Some faults are just transient software 'glitches' that go away once cleared.

MKH said:

Because I'm Mr. Impatient, I pulled the trigger on Amazon for the FOXWELL NT530. IS that OK?

Click to expand...

Loaded with the BMW/MINI software? Then yes. It is the updated version of the 510/520, which is pretty much the BMW go-to DIY scanner at home-use prices.

Normal TS procedure is to scan, make note of the fault codes, then use the scanner to clear the faults, and wait and see if any re-occur. Some faults are just transient software 'glitches' that go away once cleared.

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Y’all are absolutely invaluable! I really appreciate everyone collectively and individually for your help. The issues have been resolved.

Root cause does indeed seem to only be the 12v battery. I thought there might have been an underlying drain on the system which prematurely forced the battery to fail, but it doesn’t seem this way now.

After swapping the battery, the car was again mobile and I was able to drive it, but the drain message persisted. This was expected.

I had assumed an underlying problem existed because my EVSE was frequently topping off the new battery. Something like once every 20-40 minutes (sporadic) and for variable kWh (between .001 and .216).

I was, unfortunately, unable to account for the electrical loss. The EVSE was first connected at 10:30pm on Tuesday, and the phantom charging alerts stopped on Thursday morning at 5:10am. Perhaps a 48hr continual charge mode demanded from the ECU? Afterward, if power is retained, the HV interface releases the continual demand? There must be some logic requiring the charge request.

Regardless, I left it connected to power until the recommended foxwell arrived. Hooked it up yesterday, and was greeted with a veritable shitshow of errors which I can only assume were thrown due to the old battery decay. Cleared them, reset the date and time (for some reason, Bluetooth connections and other settings were still saved but not the efffing date). The car acted like without the date and time input, it would self destruct.

After the battery registration, we seem to be error free. I’m still left with the question of where the kWhs went after the new batt was installed? I understand the ECU may call for constant batt. Charging for 48+ hours, but why did my EVSE register kwh topping? Y’all Surely heat loss from constant charging can’t account for the metered re-topping? Maybe my EVSE metering isn’t accurate and only registers a momentary pull at arbitrarily low numbers? Maybe there was an open module sucking current but it has freed itself? I’m not really sure, but I do know y’all got me back my baby and for that I’m eternally grateful.

Draw is still happening. I've fondled underneath the driver's side seat but haven't ran into any specific module which seems warmer than other components.

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I would try under the REAR seat. That is where you find the entertainment/navigation system.

Do you have anything plugged into any of the power outlets or the USB jack in the console?

JohnWasser said:

Do you have anything plugged into any of the power outlets or the USB jack in the console?

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The power outlets shut off automatically ~15 min after the car shuts down which has frustrated those who want to use a power port to power a security camera. I assume but don't know whether this is also true for the USB port.