Key not operating central locking

[Johnbmwz4]

Hi went to use the car today and key wouldn't operate the central locking. I opened with the key and alarm went off. Car starts and everything is fine but have to lock now with key in door lock. These keys charge up when in the ignition so I went for an hours drive hoping the key will charge up and start working but it still doesn't. The spare key also doesn't operate the locking but that hasn't been used in 3 years so that will more than likely be flat. Does it need more time to charge or is it new key time.
Thanks

 

[RustyZ4]

I had this on my old z, exactly the same, I used the spare key and that charged up and worked a treat, replaced the battery in my main key and all good, worth a try with your spare