BMW E46 - Battery Replacement?

PrettyBoy

Hi guys,

I have a 2002 BMW E46 316, it was working fine up until yesterday morning when I went to get into it but the remote key wouldn't unlock the doors. I had to open the door using the key in the drivers door which set off the cars alarm, but that stopped when I turned the key in the ignition.

I came home from work yesterday evening and, again, the buttons on the key would not unlock the doors remotely. I used the key in the door again and it opened it but the alarm didn't go off this time. Tried to start the car but there's absolutely nothing happening when I turn the ignition on.

I then tried to jump start the car. It made a 'ticking' noise and the dash lights and headlights came on briefly but then went off. Tried it again and nothing was happening whatsoever.

What I'm trying to find out is whether this is due to the battery in the key or the battery in the car. I have a feeling that it's the battery in the car that needs to be replaced but I want to be sure before I buy a new one today.

Sorry if this is a stupid question, I don't know much about this kind of thing just wanted to see if anyone might know what the problem seems to be.

fmcg_scribe

It does sound as if the battery is low.

It takes a lot of energy to start the engine, so if there is something draining power, the alarm will not function and you will probably not be able to start the engine without using jump leads or a battery booster/jump starter.

If the battery is relatively new, perhaps it could be recharged but you first would need to investigate the cause of the apparent battery drain.

If the battery is the car's original battery, it's probably time to replace it but again there's no point putting in a new battery before you've established what, if anything, was draining the previous battery.

fmcg_scribe

BTW What did you use to try jump starting the car?

PrettyBoy

fmcg_scribe wrote: »

BTW What did you use to try jump starting the car?

I used jump leads connected to another BMW E46. I was very surprised they didn't work. The car is parked on a sloped driveway so haven't been able to try and push start or if I should even bother trying that? Not sure what to do now to be honest.

I only have the car a few weeks, can't check as I'm in work at the moment but I'm guessing it still has the original battery.

YbFocus

PrettyBoy wrote: »

I used jump leads connected to another BMW E46. I was very surprised they didn't work. The car is parked on a sloped driveway so haven't been able to try and push start or if I should even bother trying that? Not sure what to do now to be honest.

I only have the car a few weeks, can't check as I'm in work at the moment but I'm guessing it still has the original battery.

You are sure you connected them properly?
Very unlikely to push start as it's petrol and needs a spark.
Could it be possible the key battery and the car battery have both gone, sure sounds like that.
Whatever the chances are!

yoke

Sounds like the alternator's gone and not the battery...

Brian Larkin

check battery with a multimeter

fmcg_scribe

PrettyBoy wrote: »

I used jump leads connected to another BMW E46. I was very surprised they didn't work. The car is parked on a sloped driveway so haven't been able to try and push start or if I should even bother trying that? Not sure what to do now to be honest.

I only have the car a few weeks, can't check as I'm in work at the moment but I'm guessing it still has the original battery.

Usually, a battery's manufacturing date is marked on the battery.

Theoretically, the jump starting should have worked. Possibly, the charge in the battery is too low even with assistance.

If you could get a lend of a 12V battery booster/jump starter that has an output that matches or exceeds the cold cranking amps (CCA) of the battery, that might get the engine going. As with the manufacturing date, the battery's CCA should be marked on the battery.

fmcg_scribe

yoke wrote: »

Sounds like the alternator's gone and not the battery...

That's a possibility. Another possibility could be an "electrical consumer" draining power after the car goes into standby.

Battery drain is a symptom. OP must track down the cause.

Alanstrainor

Yup, need to figure out the age of the battery and condition of the alternator. It sounds strange to me that the doors wouldn't open, and yet the car would start on the first morning however....

You should still have been able to start the car while it was connected to the other e46 however, I reckon something wasn't connected right when doing it...

Also, it's not uncommon for the keys in these cars to go bad, that could explain the button not working, but would not explain all the other symptoms!

Idbatterim

couldnt it be the starter motor, obviously you would try the batter first, but this is what happened when my starter motor went, I got a refurbished bosch one on ebay from an Irish seller for E30, cant do better than that

PrettyBoy

Hi lads, just got home and tried to jump start it again but had no luck. I took a quick video to show what happens when I try to jump start it:

http://instagram.com/p/ubI175FsRL/

Sorry for the poor quality. My neighbour thinks the battery needs to be replaced?

ants09

PrettyBoy wrote: »

Hi lads, just got home and tried to jump start it again but had no luck. I took a quick video to show what happens when I try to jump start it:

http://instagram.com/p/ubI175FsRL/

Sorry for the poor quality. My neighbour thinks the battery needs to be replaced?

Jump her from the battery in the boot, not the connectors in the engine.

Using the connectors in the engine takes time as the power has to go to the battery and if the battery is flat could take a few hours.

Cerco

ants09 wrote: »

Jump her from the battery in the boot, not the connectors in the engine.

Using the connectors in the engine takes time as the power has to go to the battery and if the battery is flat could take a few hours.

Use the connectors in the engine bay. They are there for that purpose. The only issue you could have with this, if the connectors in the boot were loose or corroded, your battery would not get the full voltage.

bryaner

Leave the leads connected with the donor car running for a good 10 mins, then try to start it.

PrettyBoy

ants09 wrote: »

Jump her from the battery in the boot, not the connectors in the engine.

Using the connectors in the engine takes time as the power has to go to the battery and if the battery is flat could take a few hours.

Did this and it worked immediately! Seems to be running fine now, not sure what drained the battery. Thanks so much for all the replies lads, really appreciate all the helpful responses

Brian Larkin

Ah here. I have a 01 e46 a simple multimeter {cheap pound shop one will do}and check what the battery is holding 12.60+ = good -12.00 volt bad.buy a brand new bosh silverline.

allen175

Use the built in hidden OBD functions to check the battery voltage now that it is back up and running. Here is a link to the video http://youtu.be/ImCUQjmMhfM

fmcg_scribe

PrettyBoy wrote: »

Did this and it worked immediately! Seems to be running fine now, not sure what drained the battery. Thanks so much for all the replies lads, really appreciate all the helpful responses

Sounds positive. After the car was started, did you take it for a drive, say, for 10 to 20 miles? You need to give the battery a decent opportunity to be recharged by the alternator. I'm assuming here that there'a nothing wrong with the alternator and there isn't a battery drain.

Hopefully, the car will start first time when you next go to use it. If not, you'll be back to square one and you'll have to track the cause of the battery drain.

fmcg_scribe

allen175 wrote: »

Use the built in hidden OBD functions to check the battery voltage now that it is back up and running. Here is a link to the video http://youtu.be/ImCUQjmMhfM

I'm not saying that OP shouldn't follow your advice but there are different ways to test a battery, as shown here:
https://www.youtube.com/watch?v=hGMmtcsuLgc

PrettyBoy

fmcg_scribe wrote: »

Sounds positive. After the car was started, did you take it for a drive, say, for 10 to 20 miles? You need to give the battery a decent opportunity to be recharged by the alternator. I'm assuming here that there'a nothing wrong with the alternator and there isn't a battery drain.

Hopefully, the car will start first time when you next go to use it. If not, you'll be back to square one and you'll have to track the cause of the battery drain.

Went for a spirited drive last night for ~30 miles or so after I got it started. I'm in work at the moment, hopefully it will start up this evening when I get home.

wonski

From my experience when these issues start, sooner or later you need a new battery. It is just a matter of time.

Unless - as someone mentioned before - something is draining the battery during the night / some interior light left on etc.

I know some garages / dealers would test your battery for free if you want to be sure.

listermint

its getting cold. id put money on you needing a new battery soon. This is probably the start of it going south.