digital battery terminal display disable

Using a Stinger Battery Terminal with built-in LCD Digital Readout. Even though it draws low current, the terminal (neg (-) polarity) is always on. This is more of an issue when the car will sit for an extended period of time. Will need a relay setup to disable after car is turned off. Found a similar relay setup in the help section that will turn off with the opening of the driving door. How do I adjust this relay setup to work in this application as it is on opposite polarity? Do I simply inverse the 2 wire positive, 1 wire negative with the obvious 2 wires negative- 1 wire positive? Please advise

Simplest way would be to just use a single relay driven by the accessory line, with contacts 30 and 87 being used for the connection to your meter. Whenever you switch the car off, the relay opens up, and no more power drain. Do you really need it to remain latched on until you open the door? That's handy for the retained accessory function, but it doesn't sound like you need it for the meter.