[wfrancis]

I have a 2010 328i Sedan which I left in storage while I was overseas. Upon return, I hooked it up to a charger I believe correctly - I used the red terminal in the engine compartment and a part of the engine for negative.

I used a 'smart' battery charger which then produced some unexpected results. Some of the lights would flash periodically and there was a lot of relay clicking in the glove box area. Eventually, it showed a fault and stopped working.

I then tried an older dumb charger and it simply shows as if the battery is fully charged and does not charge. The car is completely dead otherwise and my key is now stuck in the ignition.

I'm concerned I may have fried something as I've read it's possible to do, though I'm frustrated as I used the correct terminals.

Is there anything to do other than pushing it out (it's somewhat trapped in a storage ******* and having it taken somewhere for repair?

[jwalker87]

There should be a big "nut" looking thing on the passenger-side shock tower that is to be used for the negative terminal. Not sure if any damage could have been caused by where you put the negative, but I would start there. The other thing is that, if your battery is completely dead, many chargers will only charge if they sense voltage present, to prevent them from shorting out when not connected to a battery/car. If that's the case, you may have to get a different charger or use a jump-starter, or have someone jump-start it. Last option would be to just replace the battery, I suppose. If it's been dead for a while then it may be permanently damaged anyway.

[wfrancis]

Originally Posted by jwalker87

There should be a big "nut" looking thing on the passenger-side shock tower that is to be used for the negative terminal. Not sure if any damage could have been caused by where you put the negative, but I would start there.

I tried that location second, but it didn't help. The 'smart' battery charger claimed there was some charge on the battery (IIRC 2 something volts) but I didn't independently verify that with a voltmeter.

[ctuna]

What was the brand of smart charger you used?
Does it give a full indication .
What about the regular charger does it have a meter?
It could take 5 to 10 hours to charge if it's any good.
Yes get a voltmeter for verify voltage if you don't have one
The engine should work for a ground but the correct place
it a hex standoff mid fender on the inside.
Also as described by jwalker.

[Fritzer]

Where did you store it? I might have to put it in storage for a couple months (same car), thinking of just buying a BMW trickle charger and plugging it in after reading this. Would disconnecting the battery over 9 months keep it's charge?

If I were you I would call a towing company with one of those massive PowerStroke F350s and have them charge and jump it the old fashion way. 100% success rate for me when my battery completely died over and over, wouldn't hold any charge.

[lowrydr310]

I always thought that batteries should be removed from the vehicle before charging using a standalone battery charger (not jump starting), or at the very least disconnected.

Do you know how old the battery is? Most likely it discharged completely while in storage (should have disconnected it first but oh well, too late to worry abotu that).

I don't have any experience with batteries that have been left discharged for long periods of time, however if your battery is over a few years old it's best to just replace it and start fresh.

[ctuna]

Yes disconnecting it would stop the constant drain .
These cars always use some energy to monitor for the
Fob and a few other functions.
A battery is a dumb device at least in an ICE car.
The only thing it cares about is the voltage being high enough
to charge so you don't have to take it out to charge it.
If there is something wrong with the rest of the car causing
a constant drain it might slow or stop charging.

[gamesfrager]

My brother's 2015 M3 was parked the whole winter period here in Calgary (ie: really long).
He had it hooked up to a trickle charger, turns out it was a bad one.
When he tried to run the car after such long time, it was dead.
Absolutely nothing. No lights, no remote, no dash lights, no clicks or any kind of indication.
I hooked up my Noco charger and it was blinking orange or something. Basically said there is something wrong with the battery.
Called BMW road side asisstance and the guy hooked up a booster. Only then it showed signs of life.
He said the voltage was below minimum required number so it didn't operate at all.
Not sure how true is that, but he ended up replacing the battery.

[nsjames]

if you battery shows 2 volts it's trashed. Long term deep discharge of a lead acid battery will sulfate the plates. It will never charge properly or have any capacity.

replace the battery.

in the future if you're going to long term storage a car, disconnect the battery.

[wfrancis]

Thank you everyone for your thoughts and replies. I had some more time to play with this today and had some luck.

The smart charger I've been using (Husky brand, I didn't notice a model number) has three amp settings - 2,6 and 10. I've mostly been using the lower two which would still generate a fault within a minute or so and just cause the relay in the glove box to come on and off rapidly, but today I decided to try going straight to the 10 amp setting.

Amazingly, this caused the car to boot for about 20 seconds before the charger tripped off. This gave me enough time to open the trunk (I had not previously mentioned the catch-22 of the trunk being shut so I couldn't get to the dead battery. This is a really bad design flaw on my car as there is no manual lock you can use based on what I've read).

The old dumb charger would not cause this to happen (even on the 10 amp setting) so somehow the so-called Smart charger was able to simulate a functional battery, albeit briefly.

I'll get a new battery and drop it in. I'll post an update here when I have more news. Thanks everyone!

[gamesfrager]

Make sure to register the new battery if it's an exact replacement. If it's different, then you need to code your car for it.

Good luck.

[wfrancis]

Dropped in a new battery of the same part number and it worked fine. I'll have a shop I work with register it. Very awkward getting the batteries in/out, but I guess that's why no one shows themselves doing it in the video tutorials. Thanks, everyone!