[AML225]

I have a 2015 M235i with a fairly new battery (~2 years). Due to the pandemic and working from home, I am not driving it much. Would there be any harm in completely removing the battery, charging it with my battery tender/trickle charger over night and replacing it? I do not have any way to charge while battery is installed in the car. Will I need to re-register the battery or anything?

[3rdcoast228i]

I don't know the answers to your questions but...

If the car will start, you would be better off going for a drive and letting it charge that way. You can let it idle before and after the drive to get some charge time You need to run that old gas out and it just plain needs to be driven if possible.

[jzeiler4]

If your battery NEEDs a charge a tender or trickle charger will NOT accomplish that. They only help to maintain a fully charged battery.

[Sportstick]

Originally Posted by AML225

I have a 2015 M235i with a fairly new battery (~2 years). Due to the pandemic and working from home, I am not driving it much. Would there be any harm in completely removing the battery, charging it with my battery tender/trickle charger over night and replacing it? I do not have any way to charge while battery is installed in the car. Will I need to re-register the battery or anything?

The optimal solution I have found. This both maintains and charges as needed. No need to remove the battery. I've used it on stored vehicles for up to 6 months so far with perfect results. Same manufacturer that BMW uses for branded chargers sold at their dealerships.

https://smartercharger.com/collectio...-multi-us-7002

[AML225]

Originally Posted by Sportstick

The optimal solution I have found. This both maintains and charges as needed. No need to remove the battery. I've used it on stored vehicles for up to 6 months so far with perfect results. Same manufacturer that BMW uses for branded chargers sold at their dealerships.

https://smartercharger.com/collectio...-multi-us-7002

That is essentially what I have, but I have absolutely no access to an outlet anywhere where I can park the car. I need to remove the battery so I can bring it to an electrical source.

[rexed]

Amazing that this charger can safely charge any type of car battery without registration. Seems like one of the world's largest car companies could do the same.

[aerobod]

Originally Posted by rexed

Amazing that this charger can safely charge any type of car battery without registration. Seems like one of the world's largest car companies could do the same.

Registration is all about the maximum current the alternator can put into the battery for it’s age, capacity and type, with a new battery having a lower resistance it can lead to excessive current causing too much hydrogen being produced and risk of damage or explosion. A smart charger comes no where near the current levels that would cause this problems.

[MarcoZandrini]

Just get out on a weekly basis and DRIVE the car for at least 20 miles at highway+ speeds!!!

[Pray for Mojo]

I wouldn't remove the battery to charge. If you close the trunk or lock the car without the battery inside you'll be SOL.

[jzeiler4]

Originally Posted by Pray for Mojo

I wouldn't remove the battery to charge. If you close the trunk or lock the car without the battery inside you'll be SOL.

No worry except the trunk as you cannot lock the car doors without a battery installed.

[albertw]

If I need to remove the battery, my current plan is to attach a small battery (probably from my motorcycle) to the terminals under the hood before disconnecting the car battery. I hope this will keep the computer happy, keep the locks working and eliminate the need for "coding" and "registration" when the battery is reinstalled. (I will use a charger to bring the voltage of the weaker battery up to that of the stronger before I make the connection.)

(I am aware that some chargers have a power supply option, but mine doesn't so I wouldn't leave the charger connected with no battery in place.)

1. It this a viable plan?

2. Could someone provide a description of the "coding" that is required after a battery is disconnected and reinstalled? What does it do? Why is it needed?

3. If it's the same battery, why is "registration" required? Is that different from "coding"?

[aerobod]

Originally Posted by albertw

If I need to remove the battery, my current plan is to attach a small battery (probably from my motorcycle) to the terminals under the hood before disconnecting the car battery. I hope this will keep the computer happy, keep the locks working and eliminate the need for "coding" and "registration" when the battery is reinstalled. (I will use a charger to bring the voltage of the weaker battery up to that of the stronger before I make the connection.)

(I am aware that some chargers have a power supply option, but mine doesn't so I wouldn't leave the charger connected with no battery in place.)

1. It this a viable plan?

2. Could someone provide a description of the "coding" that is required after a battery is disconnected and reinstalled? What does it do? Why is it needed?

3. If it's the same battery, why is "registration" required? Is that different from "coding"?

1. Should be viable for a short period of time, but no battery is fine if you use the mechanical key to lock/unlock the drivers door, then open the hood and connect a battery with jump leads to the underhood terminals to open the trunk

2. No coding should be needed, just a reset of some configuration parameters, time, radio stations, etc - iDrive tasks.

3. Battery registration is only needed if a new battery is fitted (even if the same spec as the existing one), not for just reinstalling the existing one.

[Maynard]

First off, unless you are getting low battery warning signals, this seems like excessive hassle just to 'top off' a battery. I suspect just idling it in place for as long as this whole process would take will recharge it (but that is still unnecessary). If you do go for the battery R&R route, I would strongly recommend putting the rear seats down first. In their infinite wisdom, there is no seat release inside the cabin and if you end up needing trunk access you will be SOL (there is a thread on here of a guy who made a jimmy-tool to use on those trunk pulls, but save yourself the hassle).

[E46ZHP2]

1. If it were me, I would just drive it more. Over the last 6 months, going out for a fun ride has brought much pleasure, while things have been shut down. Are there reasons you can't do that?

2. They do make solar powered trickle chargers. Coleman seems to do a nice job.

Good luck!

[morphomeman]

OP: EVERYONE is telling you that this is a bad idea and certainly not worth the hassle. Use the time that it would take for the whole business to DRIVE THE CAR, which is clearly the optimal solution.