Charging the Spare Key

[redz8]

Does anyone know if there is an aftermarket charger for the BMW Keys? That would be really neat.

If not, I may take one apart and see if I can make one myself. Just for the fun of it. My guess is that it uses some sort of induction (electro-magnets) to do the job. Similar to most electric toothbrush charging systems. :rolleyes:

[2bimornot2bim]

Does the imobilizer "forget" once the key battery dies? Has anyone had a dead key battery and brought it back to life?

[redz8]

- The Key is not serviceable.
- The failure modes are:
* Key starts the car but loses user-setting memory (needs a charge)
* Key loses synch and does not operate at all (see my next post)
* Battery completely dead and un-chargeable (key is useless)
- Replacement cost is $276.

I hope this answers your question.

[redz8]

I just tested and verified this procedure and it works.

1) Locate both your keys.
2) Get in the car and close the door.
3) Insert Key #1, turn ignition on then off within 5 seconds. (No need to start the car.)
4) Remove the Key #1 from the ignition.
5) Push and hold the unlock button.
6) Push the lock button 3 times.
7) Release the unlock button. (You should hear the doors lock, then unlock.)
8) Repeat steps 5, 6, and 7 with Key #2.
9) Get out and lock/unlock the doors with key #1, then key #2 to verify.

-- Notes --

1) You have to perform this to both keys, or else the key you left out will no longer work.

2) Don't let more than 29 seconds pass between the above steps.

[jdillane]

I just tried the procedure with both keys and no luck with either.


Hoping I don't have to have new keys imported!

[RRZ8]

Does anyone know if there is an aftermarket charger for the BMW Keys? That would be really neat.

If not, I may take one apart and see if I can make one myself. Just for the fun of it. My guess is that it uses some sort of induction (electro-magnets) to do the job. Similar to most electric toothbrush charging systems. :rolleyes:


Tony, I know that my dealer uses a (blue) key reader, I don't think that it charges the key, but maybe it does. In that case you should ask your dealer if you can buy such a reader/charger (?)

[redz8]

I just tried the procedure with both keys and no luck with either.


Hoping I don't have to have new keys imported!

It may be that a different procedure is used on EU cars. However, it is also likely that your key battery needs a recharge first.

[redz8]

Tony, I know that my dealer uses a (blue) key reader, I don't think that it charges the key, but maybe it does. In that case you should ask your dealer if you can buy such a reader/charger (?)

I'll try to find out. But, at $1.5-2K for one of those readers/programmers, we may be better off keeping the keys charged by using them at least for 30 minutes every six months, as suggested in the owner's manual.

[macfly]

Yikes, my #2 key has sat in a draw for 5 years!! I'll try it in the next couple of weeks, hopefully it can be brought back to life!

[///M Blitz]

I'll try to find out. But, at $1.5-2K for one of those readers/programmers, we may be better off keeping the keys charged by using them at least for 30 minutes every six months, as suggested in the owner's manual.

Everytime I drive the car, I use one key on the way to wherever I'm going and the other on the way back. After 4+ years both are nicely charged.

[RRZ8]

Yikes, my #2 key has sat in a draw for 5 years!! I'll try it in the next couple of weeks, hopefully it can be brought back to life!


Please let us know Andrew.....:)

[jpklecker]

I have regularly alternated between both of my keys; one used one time I drive the car, then the other key the next time I drive the car. I started doing this some time ago (bought the car new in October 2002) as after letting one key sit unused, it would no longer lock or unlock the doors. I have been doing this for at least three years with no key problems.

[fun2drive]

I've heard that you can fully charge the key yourself by simply putting it into the ignition & leaving it in the #1 position for 48 hours.
BUT - you must leave it on the street for it to be effective (just kidding).

[redz8]

I had to figure out the condition under which the key would be charging.

So, I put together a little experiment:
http://givargis.ics.uci.edu/z8/k1.jpg

As it turns out, just leaving the key in the ignition (position 0) will charge the battery :):
http://givargis.ics.uci.edu/z8/k2.jpg

And no difference if key is turned to position 1:
http://givargis.ics.uci.edu/z8/k3.jpg

Or, position 2:
http://givargis.ics.uci.edu/z8/k4.jpg

So, if you're going to charge your spare key battery, just leave it in the ignition and make sure to have your car on the battery maintainer.

Cheers!

[macfly]

Thanks so much for that very useful bit of research - I just plugged in my spare key after not touching it since Jan 03, but I was amazed to find it still had enough charge to lock and unlock the doors!

[Z8doc]

I tried it today and was amazed -- it worked perfectly with ALL functions !!

Thanks to the research above, it is now sitting in the ignition, off position, charging,
just in case.