[johndoe1983]

I stored my G23 cabriolet M440i 2021 in october 2022.

BMW has installed a trickle charger 4 amp under the hood.

Since then, my engine is making randomly relay noise somewhere on the engine. My rear defrost is flashing all the time and I lost the A/C and warmer control.

BMW tech does not understand the problem. I disconnected the 48 v battery at the big connector and let the hood open for charging.

Very sad. Search everywhere on the net without any success.

Any idea please? Thanks.

[DanG]

You are still under warranty. Why not make it the dealer’s problem?

[HighlandPete]

Originally Posted by johndoe1983

I stored my G23 cabriolet M440i 2021 in october 2022.

BMW has installed a trickle charger 4 amp under the hood.

Since then, my engine is making randomly relay noise somewhere on the engine. My rear defrost is flashing all the time and I lost the A/C and warmer control.

BMW tech does not understand the problem. I disconnected the 48 v battery at the big connector and let the hood open for charging.

Very sad. Search everywhere on the net without any success.

Any idea please? Thanks.

Have you read the following thread? Not necessarily an easy solution to charging, it appears.

https://g20.bimmerpost.com/forums/sh....php?t=1779237

[HighlandPete]

Originally Posted by DanG

You are still under warranty. Why not make it the dealer’s problem?

If I'm reading the OP's post correctly (the word "stored" is used), I'm not sure having flat batteries is a warranty issue.

Not covered here in the UK, BMW have put it in writing.

If there’s any doubt about the condition of the battery, or the car will not be used for longer than three weeks, we suggest you connect it to a BMW Battery Charger or a suitable trickle charger. Please note the car’s warranty covers the battery for manufacturing defects but not for depletion as a result of lack of use.

[DanG]

Originally Posted by HighlandPete

If I'm reading the OP's post correctly (the word "stored" is used), I'm not sure having flat batteries is a warranty issue.

Not covered here in the UK, BMW have put it in writing.

The symptoms the op is describing doesn’t seem to be related to a dead battery.

[overcoil]

Originally Posted by DanG

The symptoms the op is describing doesn’t seem to be related to a dead battery.

rodent damage ?

[HighlandPete]

If the 12V & 48V batteries are charging okay, voltages stable, and there is still a problem, I'd also be looking at the possibility of rodent damage.

[johndoe1983]

The car is in storage from 1 oct to 1 may. No licence plate on it and no insurance to drive on road. Here in Canada we have a lot of snow and I store my BM for the whole winter season. It is in a warm garage with no rodent at all.

I installed a 15 amp charger under the hood. The AGM battery give me 13.8 volt. Hood open, doors lock. 48 volt battery disconnected as per described in the PDF attached in this message.

From what I could read on the internet, the problem seem to be one of reprogramming the car (HUM???)

Since I cannot drive to the dealer I have nothing else to do than wait till spring. If I had an answer to give to the tech to help him, it would've been time saving.

It is bizarre that no one else has the same problem since there are so many mild hybrid in the world.

I included a pict of my charger. The one that the BMW tech installed is a 4amp (would get warm and not fully charge the battery) as oppose to the one I am using is 15 amp.

Thanks for your help.

[johndoe1983]

2021 BMW M440i electrical system TSB (Bulletin SIB 61 01 21)
Bulletin Date: Jul. 1, 2021
Component: Electrical system.
Bulletin Summary: 48 v battery may become totally discharged, and possible replacement needed if: a) the vehicle has been charged using a 12 v charger with the hood closed during a long stationary period, the. For example, the showroom or storage. B) vehicle
Vehicles covered in this TSB:
2021 BMW 330E, 2019 BMW 330I, 2020 BMW 330I, 2021 BMW 330I, 2021 BMW 430I, 2018 BMW 530E, 2019 BMW 530E, 2020 BMW 530E, 2021 BMW 530E, 2017 BMW 530I, 2018 BMW 530I, 2019 BMW 530I, 2020 BMW 530I, 2021 BMW 530I, 2018 BMW 540D, Show more covered vehicles... 2019 BMW 540D, 2020 BMW 540D, 2017 BMW 540I, 2018 BMW 540I, 2019 BMW 540I, 2020 BMW 540I, 2021 BMW 540I, 2020 BMW M340i, 2021 BMW M340i, 2021 BMW M440i, 2017 BMW M550i, 2018 BMW M550i, 2019 BMW M550i, 2020 BMW M550i, 2021 BMW M550i, 2019 BMW X5, 2020 BMW X5, 2021 BMW X5, 2019 BMW X7, 2020 BMW X7, 2021 BMW X7.