My beautiful brick.

[Jodokk]

We have adored our little, used, 2016 i3 for a year with no issues at all.
It began telling us that it was having trouble charging when we started the car. However the Main Battery was full each time, so it seemed to be a glitch. (Obviously it meant the 12v)
Last week we charged it during a rainstorm (a fact that may be totally irrelavent).
The next morning, christmas lights on all displays, and an ongoing drivetrain error message. Main battery showed full-charge. We've watch all the videos, and read here that it might well be the 12v battery dying. When it finally, totally bricked overnight, we ordered the requisite Remy battery, followed the procedures (disconnect drivetrain switch, neg, then pos, switch the terminsls, etc... then installed in backward order steps). Our one goof was a momentary arc/spark/zap when the socket wrench bumped the positive terminal whilst reattatching the bracket.
After attachment, and before reengaging the drivetrain switch, we turned on the car and it showed everything as fine. We reengaged the drivetrain switch, and everything seemed be fine. However it would not engage transmission or allow us to reverse or drive.
After a few hours, I tried again, and it allowed me to drive it, but the Rex engaged immediately and though the display showed a full battery, it also showed, "0" miles available. It said the (I assume) the 12v battery was low, and I should drive around to charge it. I did for about ten minutes but became a tad worried it would brick again down one these country roads, and I'd have to tow it 30 miles into Asheville to the BMW dealer. I parked.
Plugged it in, but it lit up green, as though it was fully charged.
The next day, very early in the morning, the alarm went off for ten minutes and would not respond to the fob at all. When the alarm died, it went full dark, brick. I assume it ran the 12v down below the minimum. (seriously, why not ship these things fully charged?)
When I attach the main, level one trickle-charger, the light on the charger shows that it's charging something, but, the car's fully RIP, and shows no status light at all. I'm hoping a couple of days in the trickle can charge the 12v at least enough to get the 12v up, start the REX, and let the gas engine finish charging ( like I should have to start-with).
I've ordered a charger for the 12v and the Bimmer dongle, and the FOXWELL NT510 to register the battery if I can make this happen. I'm going to try to work this out. If anyone has any suggestion, I'd greatly appreciate hearing it. Please.

 

[eNate]

I think you're on the right track getting a charge on the 12 volt. You wouldn't be the first to install a partially charged Remy and have a continuation of symptoms. Did you happen to measure the voltage on it?

 

[alohart]

It sounds like your replacement 12 V battery wasn't fully charged as you've guessed. There's no telling how long a 12 V battery has been on a shelf waiting to be sold (well, there is a manufacture date embossed on the bottom of the plastic case where it can't be read after the battery has been installed).

Two years ago when i3 batteries began failing, I ordered a replacement battery and a Foxwell NT520 Pro+ with BMW software. Had I known about the BimmerLink app at that time, I would have licensed that instead since I was happy with BimmerCode by the same developer. The Foxwell user interface is very old-school (think old-style cell phone vs. smartphone).

There are undoubtedly several diagnostic trouble codes (DTC's) set due to the low 12 V system voltage. After you've deleted them and charged the 12 V battery, I'm guessing that your i3 should be back to normal. Good luck!

 

[Jodokk]

Thanks so much for the advice, Folks. I'll give it a try and seevhow things go. I'll update as soon as I know.

 

[Jodokk]

Thanks so much for the help.
After one fail when charging the new battery, it then gave me a strong "5-light" and we popped it in. Runs like new.
Grabbed a dongle and the Bimmercode app, changed the rex milage, and registered the battery.
I can't imagine what a 40-mile tow and fix at the dealership would have cost me.
Many thanks...
D

 

[alohart]

Grabbed a dongle and the Bimmercode app, changed the rex milage, and registered the battery.

I have BimmerCode and might need to install a replacement 12 V battery soon. Please explain how you registered the 12 V battery with BimmerCode. I had thought that only BimmerLink could register the battery.

 

[Jodokk]

I used the FOXWELL NT510 to register. Seems pointless since it was precosely the same stats as my replacement version, but I did it.

 

[alohart]

I used the FOXWELL NT510 to register. Seems pointless since it was precosely the same stats as my replacement version, but I did it.

Apparently the only point is to store the replacement date so that a mechanic in the future would be able to consider the age of the 12 V battery when making a repair decision.

 

[Jodokk]

That makes sense.
Thanks

 

[I3boy]

I'm guessing you've fixed this now but the problem you have is that the new battery is not powering up the i3 systems long enough for the HV DC-DC converter to activate and take over supplying power to the 12V system.

Situation: 12v Battery failed - not able to deliver power and stay above 12v system activation threshold.
A fully charged new battery will only run the i3 for five minutes or so before dropping below the threshold for system activation. You get the red low voltage message followed a few minutes later by many, many other errors and then it enters brick mode. The REX turning on is a good thing. Its part of the recovery process.

The best approach (As documented in INSTA/D) is to get a charged battery and a battery charger that can supply 12AMPs+ . Install the fully charged battery and charger in parallel. Then you will have the i3 powered up and above the threshold for start-up indefinitely. From what I've seen the i3 consumes around 11 AMPS when powered up.

You should then find that the High Voltage controller will enable HV and then the DC to DC converter (HV ->12v) will supply power. With no charger attached you will see 14.2 volts when the DC -DC converter is active. The DC-DC converter charges the 12v battery and keeps it topped up. The 12v battery's job is to bridge the power gap between turning on the car and the DC-DC converter activating, which is usually on a few seconds when you have HV charge.

Situation: HV discharged - 12v Battery heathy but depleted and unable to supply volts above the12v threshold.
In situations where there is no HV charge but the 12v battery is healthy (but probably depleted) you can plug in the AC charging cable and this will trickle charge the 12v. Once above the 12v voltage threshold the car can be activated which should allow the HV to be charged from the AC supply. once it has above 7%(??) then the DC-DC converter will kick in.

If you have no AC available but the 12v has enough power, the REX will try and start. The REX will then try to charge the HV back to 7%(?) and supply 12v to charge the 12v battery. Nice job BMW

Summary
(1) replace the battery after 5+years and avoid all the pain ....
(2) don't ignore red 12v low voltage messages even if they flash up momentarily - (This happens in the gap between the DC-Dc activating and the 12v battery dropping below 12v)
(3) Plug in AC if in doubt.
(4) If HV is not charged and you do not have AC power available, charge the 12v and hope the REX fires up!

regards

i3boy

 

[Steve999]

FYI- I just changed my battery ( measured 35% CCA remaining based on analyzer) from 50% last year ( 2015 REX). I had one instance last winter where the battery voltage monitored at my cigarette plug dipped to 12V after sitting a few days, which also had me worried that I should change it before next winter. Picked up a DEKA AUX18L for $90 for local pickup mfg'd in May (bmw dealer quoted $560 to replace). The video by FUNCENTRIC is a great reference, but to mitigate having any bricking problems or error codes coming up, I connected a small 7AH battery from an old ATT internet battery backup unit directly to the output pins of the inverter (appears to be a direct connection to the internal 12V battery system per Shaun Dobbie Utube videos). This was done prior to the battery removal & after disabling HV. Basically like open heart surgery but keeping the "patient" alive on the heart-lung machine ...or keeping computer system powered up.

To make a long story short, worked like a charm, I had no issues with any alarms, no error codes to clear, no warnings, no waiting 24 hours for the car to function properly. Just used bimmerlink to check errors (none) then registered the battery. Attached picture below for reference. (note: other wires attached are my volt meter to make sure voltages matched and system voltage was stable during battery removal).

Biggest problem I had was opening the HV disconnect (easy once I found out there is a small catch that needs to be released on the underside of the connector - the 'orange' version).

 

[Jodokk]

This is excellent and highly technical advice! Much appreciate. We charged the new battery, and it worked like a brand new car.
I'll pay very close attention to the indicators from now on.
Thanks again! Learned very much from this.