Access to the the battery has been made more complicated with the design of the RHD fortwo 451. The battery is located in the passenger footwell. To remove it, you will need to free the centre section before lifting the carpet.

Start by removing the accessories first.

There are four screws holding the centre panel in place, two on either side and two at the top:

The centre section will come free but you need to reach behind to disconnect the cigarette lighter socket. Place it in the driver footwell with the OBD connection still in place.

Lift up the passenger carpet and unscrew the retaining clips on the polystyrene block as shown:

Pull the polystyrene block out of the car to reveal the battery.

Use a 10mm socket to free the battery strap.

Still using the 10mm socket, free the ground clamp first and pull from the battery.

Pull off the red cover from the positive terminal.

Free the positive clamp and remove the battery from the car. It will take a bit of manipulation.

Replace with a new battery and reconnect the terminals starting with the positive first.