motopokep

I've tried searching for this topic but didn't come across one. My key is 7 years young and recently the lock, trunk, and open buttons stopped responding. Not suddently, but little by little. How do you take apart the key to replace the battery without scratching the key? I see the groove down the middle on the sides all around, but I'm afraid if I take a screwdriver, I'll stcratch the hell out of the key. Is there a special tool to pop open the key? Anyone done this?

Wow, my 04 530 is about to hit 115k. It's a grandpa now. My goal is to go till it dies. Yes, I get atttached to things. My car is my friend, there's not one like it. Without me, it's useless. Without it, I am useless.

rctmthouse

use a flat head and pry it open ; my question to you is your battery lasted for 7 years? even with with the rechargeable kind (non comfort access), it doesn't last that long.

neoe60

plus, don't you have to replace with the rechargeable type?

motopokep

Done. It's not as easy as it sounds. You can't pry the key assembly open with a flathead. I had to continuously heat the key with a blowdryer, used an Xacto (super sharp surgical) knife to slowly cut all around the groove, then pried it open, carefully, and evenly from all sides, with a knife.

Next, the battery is soldered to the metal terminals. Use the same Xacto knife to carefully separate the battery. You won't find the same size battery at local stores. I went 1 size higher, 2025, instead of the 2020 that the BMW uses. Place the new battery in, carefully apply superglue to the sides, replace the other half, and take a small size clamp and gently clamp it down the middle for 5-10 minutes. Make sure not to apply too much glue as it will leak into the circuit and you're screwed. lay the key flat. when you clamp down, make sure the clamp doen't compress one of the buttons.

because the battery i found is a bit thicker, I'm left with a little space in the groove, I'll have to apply liquid rubber compound, found at your local hardware store in the electronic section, to sealt the groove completely so it's water resistant. I guess I should have used a thinner battery instead, but then I would have to solder it to the terminals so it wouldn't be loose inside the key.

This was my first time doing it and I screwed up a couple of times when I glued the key and clamped too hard and some of the buttons stopped working so I had to cut it open again and redo the whole thing, so my key doesn't look as good as before.

I don't know why BMW makes it such a hassle. I took my audi key, just popped open the battery cover, same exact battery gets sold at any store, pop it in, worked right away. I guess it's another way for BMW to make money. Strange, but completely opposite of German mentality and efficiency.

ProMed

I assume you bought a LIR2025 and not a non-rechargeable CR2025. Where did you find it in a store?

This is how it works for cars with comfort access. My fob just has a little hatch you pop open to replace the CR2032.

motopokep

no, i bought a regular battery, they didn't have rechargeables in the store. I'd have to order a rechargeable online, and I just wanted to get this over with last night and have a working key (I only have one). We'll see how long the regular battery lasts.

Now that I think about it, what can happen to the regular battery when it's placed into a rechargeable state, such as the BMW fob? is it not going to do anything, or is it going to blow up or leak, or is it going to die sooner?

maybe I should get a rechargeable online.

ProMed

I'm not sure what happens if you put a Lithium Manganese Dioxide battery in a charger designed for an LR/LIR battery. May be nothing, may be something bad?

ProMed

Found this on wikianswers (which means it may or may not be correct):

Can cr2032 lithium button cell be recharged?

Recharging lithium CRxxxx batteries is not generally possible due to the chemistry and components used in these button batteries. In fact, recharging them can cause them to leak, become very hot, burst, or cause a fire.
There are similar sized Lithium Ion and Lithium Polymer batteries that can be recharged, though they are rare.

Read more: http://wiki.answers.com/Q/Can_cr2032...#ixzz1PZDkQSVG

luigi524td

Only the comfort access fob has a battery that is easily replaced. NON-CA fobs charge the battery when inserted in the the corresponding slot. I don't think it's advisable to replaced a defective battery with a conventional Lithium button battery as they are NOT meant to be recharged. As an earlier poster noted that may cause a problem that will find you having to replace the entire key fob.

motopokep

you guys are right, can't use regular battery in a chargeable fob. just ordered the panasonic v2020 off of ebay, hopefully will get here fast, i'll risk it driving short distances for couple of days till it gets here.