There is herein described a charging unit adapted for insertion into a mobile device to enable a charging of a rechargeable battery in the mobile device, the unit comprising: at least two electrical charging contacts for receiving a potential difference from a power source; a blocking device for blocking energy leaking through the at least two electrical charging contacts and out of the rechargeable battery to ensure a neutrality of the at least two charging contacts when the charging is inactive; and a logic circuitry for controlling the charging of the rechargeable battery of the mobile device by activating the charging based on the potential difference received at the at least two electrical charging contacts.