Storing M and battery

[us722]

Quick one guys. I’m about to store my M3 for next few cold months. Can I remove the battery to bring it inside/charge? Or will it need to be coded come next spring?

I would rather not go through the hassle of coding/registering the battery so what’s the best way to keep it in good health through winter?

Thx

[nrubenstein]

Yes and no.

It's not actually "coding" a battery. You're just telling the car that it has a new battery so that it will charge it like a new battery, rather than an old one. (I think the real intent was to encourage service visits - it's not like the E9x gets meaningfully different battery life than previous cars.)

[us722]

Got it. So it will need to get registered? Might as well put trickle charger then...

[us722]

How about simply disconnecting the negative terminal on the battery?

[ha9981]

You can disconnect the battery on negative terminal.

You can remove it and bring it inside.

You can put it on a battery tender (not the same as trickle charger) from under the hood terminals.

Either way works, obviously the very best option is to bring it inside and connect it to a battery tender. Since it's a big chore to remove the battery, I connected a battery tender under the hood.

Also no re-registration of battery needed. You do that when it's replaced with a new one.

[Helmsman]

Like ha9981 says, no issues to disconnect (+re set the modules properly...). Personally would leave the battery in the car. Fully charged (!) it doesn't have issues with cold temperature.
Ps. "Coding" only needed when replacing with another spec battery.

[94jedi]

If you have access to electric, just put a ctek battery tender/charger on it.

[Staszek]

Where are you storing it? I would put on a battery tender, that's what I do every winter. No issues after 7 years.

[roastbeef]

Originally Posted by 94jedi

If you have access to electric, just put a ctek battery tender/charger on it.

This is the best solution if you're able to.

[nrubenstein]

Originally Posted by us722

Got it. So it will need to get registered? Might as well put trickle charger then...

No. It'll be the same old battery. No need to register it.

[nrubenstein]

Originally Posted by 94jedi

If you have access to electric, just put a ctek battery tender/charger on it.

It always boggles my mind that people want to leave their expensive cars plugged into the power grid for a really long time, exposed to power surges and dependent on a cheap battery tender to work continuously for months or years.

Once you've seen a battery tender boil over or blow up a battery, you get a lot less enthusiastic about this.

And to be clear - I have a CTEK. It's fine, aside from the extremely unreliable button. I also have "battery tender" brand tenders, and a larger scale charger. I'd much rather charge the car for a day every 3-4 weeks than leave it plugged in continuously.

[6ixSpd]

I've never had any issues with CTEKs or battery tenders plugged in 6 months at a time on multiple cars for the last decade. It's extremely common up here.

[Helmsman]

Originally Posted by nrubenstein

It always boggles my mind that people want to leave their expensive cars plugged into the power grid for a really long time, exposed to power surges and dependent on a cheap battery tender to work continuously for months or years.

Once you've seen a battery tender boil over or blow up a battery, you get a lot less enthusiastic about this.

And to be clear - I have a CTEK. It's fine, aside from the extremely unreliable button. I also have "battery tender" brand tenders, and a larger scale charger. I'd much rather charge the car for a day every 3-4 weeks than leave it plugged in continuously.

Thats what a trickle charger is for. In my boat I had it on around the year except for when I'm out using the boat. Unfortunately no power in my garage or my CTEK would be on...