kevofcov wrote:

Can anyone tell me;
I'm going to keep a spare key in a draw at home. It will eventually go flat - will it still start the car?

Kev

Swap them over twice a year Kev....they'll last 6 months

Quote:

I'm going to keep a spare key in a draw at home. It will eventually go flat - will it still start the car?

yes the vehicle will start, in fact the vehicle can be opened using the key through the drivers door lock barrel.

When the key is inserted into the ignition barrel the transponder coil sends out low frequency to wake up the transponder embedded in the key blade. If the immobiliser sees the transponder code, which is unique to each vehicle, the immobiliser gives the all clear message to various ecu's to allow the vehicle to start.

If the battery is flat the vehicle can be started. Once started leave the engine idling for at least 6 minutes this will synchronise the rolling remote fob code between the key and the immobiliser ecu. This should re-enable the remote fob buttons. And obviously the more time the key is in the ignition the more charge time it gets.