I have seen several battery cut of switches installed in DeLoreans. I have never been impressed with the bulk of them currently available. I have since come across the Master Disconnect Switch from Pollak. It is a heavy duty and sturdy switch. They have been manufactured for years, originally being made in the United States. They are now being manufactured in Taiwan by Pollak. I have recently come across a stock of USA made switches and am offering them for sale here.
Please see my article on DeLorean Directory for more info: