Finally after 2.5 years of neglect my key battery needed replacing. Sods law the large orange warning light first came on while my wife was using the car, which caused her some anxiety .
I changed the battery myself. Removing the emergency key was easy, But the point of this post is that the next stage was more difficult than I expected. You have to prise the two halves of the key apart by twisting a coin in a gap between two blocks of plastic. This needed quite a bit of force to be used, and I began to question if I was doing it right and feared I might break something. Eventually I succeeded. Once open the battery is easy to replace and the key is easy to snap shut again.
The manual recommends wrapping the coin in cloth to protect the key. I didnt bother with this, and there was no damage. I dont think wrapping it would have made it any easier. It also warns to be careful the buttons dont drop out
From what I could see this didnt seem likely.
I carried a spare Cr2032 battery in the car with the idea that I could change the battery if necessary while away from home. But I dont think I would have had the confidence to use that much force on the key while away from the security of being at home with a spare key to hand. And my wife certainly wouldnt. But having done it once it will no longer be a problem.
I'd recommend not leaving it to the last minute, although I suppose you could get the dealer to do it.
