[Znomorph4theWin]

Originally Posted by G80indy

Occasionally I’ll toot the horn to test the connection.
I’ve also found the tire sensors are not spot on in the app. I measure to 0.1 lbs with my digital gauge and the tire pressures are exact. The sensors read 3-4 lbs high

Lol. My sons bedroom is located on top of the garage. To test connectivity, I choose to do the flash the lights option so I don’t scare the crap out of him….

[Znomorph4theWin]

Originally Posted by M4CompConv/X7

Almost the same thing happened to my 2022 BMW X7 4.0 today... except there was no flickering. No start. No dome light. No dash lights. etc. etc.
Had to have it dragged onto a flatbed on the way to the dealer.

It’s a horrible feeling isn’t?? Hope all is good. Please post the findings/outcome!

Note when this happened to me, I reluctantly made arrangements to get the car towed by BMW roadside assistance to my dealer. However, The very idea of them having to extract my brand new car from my tight garage caused my anxiety to go off.

Turns out, after I read suggestions from those who responded to my post, I chose to try boosting the car first (my wife’s Ford Escape was parked next to the M3 in the garage). It started immediately. I then took it for a long enough drive to bring the voltage back up. After a 30min boot around my local streets, I attached it to the charger and it began charging normally.

Have not had a problem since then. However, like I mentioned in my previous post, while the car is back in storage (winter is back in Toronto ,) I don’t let it “sit” on the CTEK charger. I don’t trust it. Now, once a week or so, I’ll connect the charger, let it charge the battery to full capacity, then disconnect it.

Cheers

[AHall]

Originally Posted by Znomorph4theWin

It’s a horrible feeling isn’t?? Hope all is good. Please post the findings/outcome!

Note when this happened to me, I reluctantly made arrangements to get the car towed by BMW roadside assistance to my dealer. However, The very idea of them having to extract my brand new car from my tight garage caused my anxiety to go off.

Turns out, after I read suggestions from those who responded to my post, I chose to try boosting the car first (my wife’s Ford Escape was parked next to the M3 in the garage). It started immediately. I then took it for a long enough drive to bring the voltage back up. After a 30min boot around my local streets, I attached it to the charger and it began charging normally.

Have not had a problem since then. However, like I mentioned in my previous post, while the car is back in storage (winter is back in Toronto ,) I don’t let it “sit” on the CTEK charger. I don’t trust it. Now, once a week or so, I’ll connect the charger, let it charge the battery to full capacity, then disconnect it.

Cheers

I also used the BMW charger with the different modes. I am curious what the charger displayed when you went to the car before it went dead. Was it on status 7 or 8? It does not make sense the battery would discharge to the point of failure if the charger is properly connected. So I am curious about the charge status prior to failure.

[Znomorph4theWin]

Originally Posted by AHall

I also used the BMW charger with the different modes. I am curious what the charger displayed when you went to the car before it went dead. Was it on status 7 or 8? It does not make sense the battery would discharge to the point of failure if the charger is properly connected. So I am curious about the charge status prior to failure.

Crazy thing was that it was on status 7 or 8. I can’t remember exactly but the light was GREEN thereby giving me no cause of concern. What was weird was when I disconnected the charger from the battery terminals (but charger still plugged into wall AC outlet), the charger still let up green 7 or 8. How can it register a charge to a battery that is no longer connected? At the moment, I did not put too much thought into it. But hindsight is 20/20 so they say and since then has made me reconsider leaving it plugged into the CTEK the whole time. I don’t trust it as a set it and forget it solution. I will just periodically charge the battery every few weeks to top it off.

[G80indy]

Someone please get one of the Bluetooth battery monitors I mention above so we can discuss ! 🙏🏻

What I have found is the car sits for long periods and it maintains 13.3 V without dropping! The nature of lithium batteries, holding voltage until it absolutely, let’s go.

I am wondering what your readings would be right before the batteries are disconnecting with UVP kicking in—- at what voltage level… and how fast that decline in voltage occurs.
I am very curious.

[vinha916]

CTEK (56-353) MULTI US 7002 12-Volt Battery Charger,Black

This is what I have, if leave it on 24/7 in winter mode.

[G80indy]

Originally Posted by vinha916

CTEK (56-353) MULTI US 7002 12-Volt Battery Charger,Black

This is what I have, if leave it on 24/7 in winter mode.

Not recommended for a lithium battery ….

This is the one you want
CTEK 56-926 LITHIUM US | Fully Automatic Lithium Ion Phosphate LiFePO4 Battery Charger | 5.0Ah - 60Ah | Maintenance Charging up to 120Ah https://a.co/d/gjcPzUi

[kjx]

Saw M3 CX and “completely dead” in the title and knew instantly what was up.

It’s the power draw from the ultra-wide screen TV on the dash.

I kid. I kid. Carry on.

[G80indy]

Haha
My CTEK makes my M3 a plug in hybrid
😜

[vinha916]

haha my M3 getting charged more than EV

[Pmundrey]

it might be self explanatory but just wanna check in. I drove my car last Friday and today I uncocked the car to get something out of it and locked It back. later on I checked the bmw app and it showed the status as "unlocked" still. later on at night I sat in the car and the message came up on the dash "start engine low battery. Is the battery supposed to be going low after a week of not driving etc? Taking it to the dealer in the am. might need to get a battery charger.

[Mike02z]

I’ve had multiple BMW’s and never trickle charged them from the battery. Works just fine connected to the jump point and a ground. I use the comfort connect and hardwire to the jump points.

[AWDSOME]

So heading into my first winter and I won't drive my car in the salt.

I have a Noco Genius 10 charger, sounds like it would work fine for top off charging during the hard Utah winter. Will it be fine or do you really need a CTEK charger?

[ChrisM4]

I think the best solution to this predicament is a set of winter tires and wheels and enjoying the car year round

(That’s what I do)

[turbojg]

Just get yourself a cheap digital multimeter and monitor the battery voltage with the charger disconnected. See the attached chart for state of charge info.

[geko29]

Originally Posted by AWDSOME

I have a Noco Genius 10 charger, sounds like it would work fine for top off charging during the hard Utah winter. Will it be fine or do you really need a CTEK charger?

It claims to support Lithium Iron Phosphate batteries, as long as there's a Battery Management System, which our cars have. So I think you're good, as long as you hook it up such that the BMS is in the circuit (which is probably the same for the CTEK).

[turbojg]

I have to wonder is after the charger goes into the maintenance step if it will revert back to supplying steady full charging voltage to replace the energy lost with opening the doors (and having every thing power up) numerous times while in storage. If it doesn't then each time the door is opened the battery will drain further and further.

Another thing of interest is that Lithium Ion batteries in long term storage should be kept at about 60% - 80% charge rather than full charge. My new Apple Macbook only charges to 80% and if I am going to use it heavily that bay on battery I need to finish off the charge to 100% before disconnecting it from the charger.

[geko29]

Originally Posted by turbojg

I have to wonder is after the charger goes into the maintenance step if it will revert back to supplying steady full charging voltage to replace the energy lost with opening the doors (and having every thing power up) numerous times while in storage. If it doesn't then each time the door is opened the battery will drain further and further.

STEP 8 PULSE
Maintaining the battery at 95–100% capacity. The charger monitors the battery voltage
and gives a pulse when necessary to keep the battery fully charged.

The voltage for this step is listed as 13.4-13.8V.

[Limegrntaln]

Originally Posted by Pmundrey

it might be self explanatory but just wanna check in. I drove my car last Friday and today I uncocked the car to get something out of it and locked It back. later on I checked the bmw app and it showed the status as "unlocked" still. later on at night I sat in the car and the message came up on the dash "start engine low battery. Is the battery supposed to be going low after a week of not driving etc? Taking it to the dealer in the am. might need to get a battery charger.

I hope not. Im about to drive mine, today, and I havent driven it, or awakened it from sleep, since the 19th.

[dstampfer1]

Originally Posted by Mike02z

I’ve had multiple BMW’s and never trickle charged them from the battery. Works just fine connected to the jump point and a ground. I use the comfort connect and hardwire to the jump points.

Connection to the negative post there is easy (if you have the correct size Torx bit to loosen it). Is there a similar sized post at the positive terminal? I pulled the plastic cover off and see a post which also has Torx style drive, that's larger?

[Mike02z]

Originally Posted by dstampfer1

Connection to the negative post there is easy (if you have the correct size Torx bit to loosen it). Is there a similar sized post at the positive terminal? I pulled the plastic cover off and see a post which also has Torx style drive, that's larger?

It’s a T45 or T50 as I recall. Just like the ground it simply unscrews.

[turbojg]

Originally Posted by G80indy

Occasionally I’ll toot the horn to test the connection.
I measure to 0.1 lbs with my digital gauge and the tire pressures are exact.

Before you fuss over setting to .1 psi accuracy you should check the accuracy specs on the digital gage. A lot have an accuracy of ½ psi despite their reading in .1 psi increments.